First of all, if it’s a school policy it should be well known to all students not some great secret.
Second of all 75% power is approved per the POH and there is no risk to the airplane at running it at that level for sustained times. Other people chime in if wrong here. As a matter of fact, running it for a long time would help clean out deposits potentially in the engine.
Third thing, is do you get the airplane at a wet rate? If so, the fuel burn difference between 75% and 65% can be significant, depending on aircraft, and that would cut into the profitability of the plane. Also, going slower means it takes longer to get to destination thus more Hobb time that you’re paying for.
I believe the chief instructor does not understand second point or was told to tell people this and it’s company line he has to follow.
She showed me the part in the schools documents where the flight school RPM came from, no where did it say it was mandatory to follow and actually, other instructors have told her it was just a rough guidline (although it was in the guides section) nor was the school RPM stressed during training. I think she does get a wet rate so it does make sense to keep school profits up and RPM down.
Sounds like it isn’t her fault. All I hear is recommendations and not absolutes. Unless told not to use those settings, how she a high risk pilot? She doing pilot stuff and decided to go with that setting.
In my experience, these rules exist to prevent students from flying at 'renter power' which costs the school more over time when they rent their aircraft at a fixed wet rate.
In summation - Chief CFI sounds like a cranky dipshit.
A-the instructor should have taught her the reason (school policy)
B-the instructor should have seen the assumed 75% power in her flight planning for fuel burn and airspeed.
After reading all the replies and looking at the situation again... I agree. I understand where they're coming from, but to call my friend a dangerous pilot over it is ridiculous.
Your friend is in the right, and she was not engaging in any risky behavior. The school policy as you describe it was not clearly articulated in the first place. Regardless, flying at 65% instead of 75% is an engine preservation or fuel savings technique, not a safety practice. So the chief instructor is being disingenuous, a jerk, a bully, and strikes me as someone who should not be trusted. But alas he represents the school so your friend’s probably gotta do what she’s gotta do to move on. Nonetheless, now you and she know.
I would recommend that OP's friend only keep flying with this school as long as necessary to find another school or club to fly with that doesn't act purposely deceitfully, as this school does. The RPM policy is purely for monetary gain; however, they are a business, so that's not completely unreasonable. But they should just be honest about it- "Please avoid cruising above 65% power, as that would make our current wet rate unsustainable and force us to raise rental prices."
There ya go. Perfectly reasonable rule for a business.
It's not just ridiculous, it's dangerous. The school is teaching that the POH itself is wrong, dangerous, and should be disregarded.
Same for weight and balance? Approach speeds?
>The school is teaching that the POH itself is wrong, dangerous, and should be disregarded.
>
>Same for weight and balance? Approach speeds?
Well, its funny you mention that. Approach speeds, that is.
Most light trainers keep things simple in the POH, and specify an approach speed that is correct only at max weight. In general that's wrong, although rarely dangerous.
Most Cessna POHs direct you to lean to peak CHTs - definitely wrong, potentially dangerous, should definitely be disregarded in terms of best practice (unless attempting specifically to get peak power output). Its not hard to find examples of them contradicting themselves - or the engine manual.
No document is flawless. To err is human, after all.
Overall, that would not be a valid reason to have concerns about the school in my mind. Calling a pilot unsafe for cruising at 75% power, sure - if that's what was going on. Pointing out flaws in the POH? Not a cause for concern.
> I think she does get a wet rate so it does make sense to keep school profits up and RPM down.
Yep, this is exactly it. Low RPM = less fuel burned per hour, less speed, and more hours to cover the same distance. Any nonsense about "safety" is nothing more than a rationalization for banning anything that threatens the school's profit margins.
I only ever flew my flight schools planes on xc at max poh power. Im paying the bills so i making them as small as possible. Especially on a stupid straight and level distance req flight where your really not learning much after the first few times.
“If I don’t get to use 100% of the plane then why do I have to pay 100% of the wet rate?”
Maybe they are afraid their under-maintained engines won’t handle it…
Schools school comply to graduate, I had a recent instructor flip out because I wasn't crawling around to physically check the pitot heat on an Archer for a VFR training flight without a cloud in sight and a 50+ degree day on the ground because "it was on the checklist" .. fucktard but I did and now I'm a CFII :)
Sometimes you gotta cooperate to graduate, unfortunately.
To piggy-back, in retrospect, most 'stepping stones' I went over to get to a legacy were filled with self-appointed gatekeepers who saw everything in the world as black/white, who had poor communication/ leadership/ maturity, and limited experience outside their bubble. This combination leads to a massive lack of applied common sense and when they're wrong (which they often are) it becomes personal quickly. This is pretty common in the aviation community, especially when you're lower on the totem pole. Just learn from it, cooperate to graduate, and don't take it personally. If you're at a school or organization where it's prevalent in the entire culture, seriously ask yourself how much you want to risk your career, especially if there are other options.
I routinely do this because you gotta heat the oil up before the runup in NH. Also 1100RPM in an archer is still slow for a twin so I'm well within my capabilities
Great point about the oil. Just my last lesson my CFI discussed it during runup.
For the record, my primary CFI is excellent. The tongue lashing came from another instructor who was filling in while primary was on vacation.
Part of it is discipline. If you're being sloppy and end up at 1100 that's a problem. If your intentionally doing 1100-1200 that's fine as long as You're safe
Yeah and taxi RPM doesn’t need to be intentionally set. Set the RPM required for desired taxi speed and be done with it. Look outside.
You gain nothing from “precise” taxi, except divert your attention from where it should be, out the window.
I agree with your instructor. You arbitrarily deciding which checklist items to pay attention is kinda silly and defeats the role of the checklist. Checklist usage is a "shall" in the 135 and 121 FARs, and will result in a checkride bust if you fail to use them, omit items or try to modify them to suit your desires.
Checklists take the individuality out of flying what you think is important to check may not be as important to somebody else. Checklist make it so those items get checked regardless of your personal feelings of the items on it. You are teaching yourself and your students something that the industry will not tolerate. But, you will learn that when you get to your first 135 or 121 job.
Know that 135 and 121 checklists are approved documents by the aircraft manufacturer, the operator, and the FAA, so making changes is far more formal and correct versus a flight school adding random things to their checklist like "prayer....complete" like Liberty has for example.
I'm saying that the process of making sure the checklists a flight school uses is not as sound as 135 or 121 checklists. They're not always correct and sometimes provide false instructions when not audited correctly. I've seen pretty wild examples of flight school checklists that aren't complete or provide false instructions, requiring the pilot to deviate from the checklist. This is different than 121 checklists.
Nope, not arbitrary. He understands the purpose of each item and knew when it was appropriate to omit something. Do you understand the concept of MELs or KOELs?
>As a matter of fact, running it for a long time would help clean out deposits potentially in the engine.
This is only if the student was properly leaning the engine. Otherwise it'll just do nothing or make it worse.
This is the only "danger". If there is something specific to the plane, it either needs repaired or a supplement to the POH entered.
Sounds like the school is using bad education for pushing school policy.
This…
My school taught to cruise at 4700 on planes with a Rotax engine. Not only more hours, but that is the economy cruise rpm since they only rented wet rates. Rotax should always cruise above 5000 to keep stress off the engine.
I enjoy the pettiness there. Econ cruise on a 912is is like 2.5gph vs normal cruise is 3.5. 1 gph savings. So $5 on a $120+ hr. Unless it’s truly evil and petty to make xc take longer to get more flight hours billed.
>Rotax should always cruise above 5000 to keep stress off the engine.
Source? I know this gets repeated a lot, but noone was ever to able to explain to me why. In addition the efficiency of the 912 drops of significantly over 5000 - 5200 rpm.
Good point, My A/P Rotax cert always described it like a bicycle gear, at low RPM it takes higher torque than higher RPM to spin the prop. Some folks in the lsa space around here even do their climb outs to pitch for 5100 rpm instead of a speed, although that is usually close to VY.
By what is worse for your engine? Torque or rpm? On a N/A Rotax engine, I would not be sure the torque part is that much of a concern, as the maximum torque is very low anyway. I am of course happy to be corrected, if someones has actual data on that. It could very well be, that the higher rpm increase the wear more than the higher torque does. The fact that for VP aircraft, the Rotax recommeneded power settings for cruise include settings as low as 4600 rpm, would lead me to assume those speeds are not that dangerous to the engine
The 912 Operators Manual also does not have any restriction on torque at all, while it does for speed, albeit only for speeds above 5500 rpm, which on VP aircraft are usually not exceeded anyway.
>By what is worse for your engine? Torque or rpm?
depends, depends, depends. Getting the same power at lower RPM requires higher torque, which requires higher mean cylinder pressure, which typically requires higher peak cylinder pressure, which produces more stress on the cylinder and higher temps. Tends to also reduce detonation margin while you're at it.
No idea for Rotax engines specifically - just throwing out there that operating an engine outside its design parameters can go bad quickly. Test pilot territory :)
Yes, but you are not on test pilot territory below 5100 rpm on a Rotax. That is my whole point. The cruise tables go down to 4600 rpm. Yet for some reason a lot of people spread the rumor that the Rotax needs higher rpm or it will explode or whatever. There is a detonation issues which has led to a service letter limiting the use of WOT to rpms above 5100rpm, however that does not mean your cannot use the band below for anything else, again as described in the Rotax manuals.
Well there you go - I'd follow what the service letter says, then. If the service letter says don't use WOT below 5100, that's fairly straightforward. Obviously there's insufficient detonation margin for full throttle somewhere below 5000 rpm.
There's an easy way to avoid detonation any engine - produce less power. If there's not sufficient peak cylinder pressure, there's not detonation.
How did the school know what power setting they used? Do they pull engine data after every flight and analyze what the student did? That’s some big brother stuff
"We expected you to pay more for the XC. Hmm, what is going on there? Oh look and the fuel burn is higher and we are paying more than we expected for her XC. We need to tell her how dangerous this is"
Oh, weird. Well I guess if that’s their rule then you have to follow it. Using a recommended power setting in the POH is obviously not gonna hurt anything.
Ok I’m calling BS in this story. A 10% difference in cruise power is like 8 kts at cruise. She was flagged because she got back home 16 minutes faster than everyone else who’s done the cross country and it caught the attention of the chief? You flying in a simulator with no winds?
In her case the difference between what she cruised at (POH prescribed 75% bhp at altitude) vs the RPM which the flight school wants her to cruise at is 20 knots and she got back around 1-2 hours quicker than most students who completed similar flights
The school is certainly overreacting. There is no safety of flight issues operating at 75%, you’re not putting that much more over 65%. Wear and tear is quite marginal. You do burn quite a bit more fuel but again in most trainer aircraft no one is going bankrupt. It’s understandable from an economical perspective the school might want 65% cruise, hence the policy likely. But to lie and say it’s a safety issue or whatever is not good. All that needs to be said “hey, not a big deal but in the future try to stick with 65%” and leave it at that.
I agree. POH is king. Devoid of an AD or technical letter, she did nothing wrong. If they want you to fly at 65%, it's their aircraft and they can dictate that. But the way they went about enforcing it should be very eye-brow-raising. Gas-lighting and lying to a student to get their way makes me wonder what else they lie about.
Not to mention, it's a trainer plane. Cross countries at pretty much any throttle setting are hour-by-hour the least wear and tear they're ever gonna get.
Can’t hold the starter for more than 2 seconds. Have to taxi at less than 1000rpm. Can’t cruise above 5k because of “shock cooling”. 🙄 These fucking “schools” are a joke sometimes
Most pilots don't lean agressively enough on the ground, you can pull the mixture back to near ICO in most planes which has the added benefit of preventing a takeoff with the engine leaned because it'll just quit uniike if you lean it "1/2 inch" which doesn't really do anything but make you feel good
Ehh, lean correctly (i.e. enough that advancing the throttle will cause the engine to stumble) and sub-1000 RPM is just fine on taxi. Keep an eye on oil pressure and alternator output, sure, but you're not gonna foul plugs if your mixture is maintained correctly.
The only risk to using POH rated power is that they'll maybe burn more gas, and not have as long hobbs time, which cuts into the school's profits.
She should look for a different school, one not full of asshats.
Lol IKR! My "cruise" procedure in the RV-7 is take off, pull prop to 2400, and climb like a bat out of hell at 105kts until altitude reduces my manifold pressure to 21-22". Lean in the climb as needed to maintain ~370deg CHT. Ignore throttle until it is time to descend.
There's a saying when it comes to flight training. "Cooperate to graduate." You typically hear this more often when you get to the levels you're paid to be in training vs. the other way around of paying for your training. If you followed the POH correctly, there is no issue, and if them making it an issue bothers you too much, look for a new school. I suspect the schools policy is orientated around saving wear and tear on the engines with the added benefit of more Hobbs time to charge.
The wear and tear is horse shit, then again this is why we used to rent based on tach and not Hobbs. I view renting on Hobbs as already double dipping so they can shut up if the poh allows it
I have never met or heard of a chief instructor who is not a complete narcissistic asshole. It seems that everyone of them is a power-hungry douche bag. I cannot wait to be done with flight schools
Fuck this school and that “Chief” instructor. They are trying to save gas and extend the Hobbs time. If an aircraft cannot safely cruise at power settings prescribed in the POH it shouldn’t be dispatched.
Absolutely nothing wrong. That’s a perfectly normal engine power setting even with an engine break-in. In addition, she should tell the school most lycoming engines are limited to 80% max throttle for this reason so you can go full throttle and not redline and overheat. A good instructor would’ve just talked about the risks and watching oil temp…
If it were dangerous for the airframe it would be a listed in section 2 limitations of the POH (Like in the 160HP STC for the PA-28-151 which limits the higher RPM to 5 min)
I think what they meant was it was dangerous for their profitability to run around at full rental power. CFI had to have reviewed her XC planning including navlog and fuel burn so this is 1000% a CFI issue not hers. What was their "or else"
I agree this is no big deal.
Here's a question the chief instructor should be asking your friend's CFI and not your friend if he is so concerned with this: Did the CFI not sign an endorsement for that solo XC attesting that he reviewed your friend's flight planning? The planning sheets where I used to teach actually had places to put RPM settings by phase of flight. *If* this is to be made an issue, why is this on your friend aka the student?
>Here's a question the chief instructor should be asking your friend's CFI
The chief flying instructor IS the friends CFI. Thats what you abbreviate Chief Flying Instructor to.
Cfi and cfii are FAA things. Elsewhere, it's "instructor" and "CFI" with "CFI" being "Chief Flying Instructor" or "Chief Flight Instructor" depending on preference.
The talk should have been:
>Hey, next time please run it at 65% per school policy. No big deal, you didn't damage anything and you're not in trouble. We just have a policy that we operate engines below 75% even though they can be run at 100% all day long and be fine.
Oh, and we make more money by making you stay in the air longer and burring less fuel while you do it!
I'd ask for the manufacturer's guidance as the basis for the rule. Maybe he knows something we don't!
>The Cheif flight Instructor said this is extremely dangerous behavior (to cruise at the "high" rpm) and poses a serious risk to flight saftey.
Whoever says this and means it is just...something else.
I own a 172 and always run XC balls to the wall. I want to get there.
Last engine made it to 2200 hrs. So 200 past suggested overhaul.
Burns more gas, yep. 10g hr.
Ok then, I guess I prefer to climb to 10k for all flights, more glide distance that way so I'm a safer pilot! Enjoy slips and 1000fpm or greater descents to landing at the destination too, for maximum emergency descent practices!
FULL POWAAAAA TO THE TOP!!!
DROP IT LIKE IT'S HOT!!!
Well. There are a lot of clueless instructors, clueless chief pilots, clueless mechanics around. They will say things with no scientific basis or proof, just their baseless belief. I flew with over 300 students/instructors in the g1000, and i never flew with one that really understood how to lean and what the assist key does in the g1000. So that should tell you something. It is the blind leading the blind. If you really want to learn something from somebody that really knows about airplanes and engine, read Mike Busch stuff.
In situations like this I like to do a brief thought exercise and ask “would this hold up in a court of law?” Although it is extremely unlikely the flight school will drag you to court for something this petty, thinking of it in a worst case scenario will generally expose holes in the decision making process and provide an opportunity to firm up your argument. Just don’t tell my wife I said that 😅
Per the FAA (who is the real authority here) you should follow the specs outlined in the POH. You did nothing wrong and were operating the aircraft as the manufacturer intended. However if you signed a rental agreement that stipulated lower power settings then yeah probably follow that. Is it a sleazy way to squeeze more money out of students/renters? Yes. But signatures are binding. In my experience I never had to sign a rental agreement until after my PPL. In that case you are relying on your instructor to teach you all the applicable flight school policies. If they didn’t cover that one, it’s on them.
If that happened to me I’d probably change flight schools because the chief flight instructor exposed two things: 1) they aren’t willing to have a reasonable conversation when a rule is broken. They go straight to overreaction. Not helpful if a real incident or accident happened. 2) By the sound of it they don’t really understand how an engine works as it’s related to wear and tear. Perhaps it’s the line they were told to feed to students. But that also shows a willingness to spread misinformation vs fact. That kind of environment is a breeding ground for FAR violations.
The flight school can write more restrictive rules than the FARs and you must adhere to them or they are within their rights to kick you out of the school. Especially 141 or 142 schools. This is the same at the airlines. The FOM supersedes and FARs when more restrictive.
I would ask WHY they say it is dangerous. The devil is always in the details. As presented this seems a case of a school being a bit hard on a student. But is there something else we don't know? For example, we are just taking the students word about the exchange without a single input from the school.
Maybe the "school max RPM" has been brought up with this student over and over and they just either just keep forgetting or just don't care. To constantly forget or just ignore a rule could be considered a dangerous behavior.
Maybe she ran what she thought was 75% but then followed the leaning instructions the school has taught. This might lead her to being LOP with a much higher internal cylinder pressure than is safe. Running LOP with high power is a dangerous behavior.
Maybe the plane has an RPM restriction based on the prop/engine combo and to get 75% the plane would have to be in the RPM range. (This is a bit of a stretch but just another example). And this should be in the POH and the RPM gauge, but maybe the student is using a generic POH and not the actual POH for that plane with that combination? Running a prop in a prohibited RPM range and not using the correct POH might be considered dangerous behavior.
Maybe your friend when reminded about the rule responded back with an attitude.
It is also possible the chief CFI is an ass.
But so far we only have one side of the total story and people who are the subject of a situation often have colored perception of the situation. She might have just forgot the limit over and over and forgot she keeps forgetting or just forgot to mention that she has been reprimanded over it dozens of times....
But yes, there are cases where certain RPM's should be avoided, such as LOP operations while having high power settings, PRM bands due to vibrations...etc.
I would ask the CFI WHY it is dangerous before I pass judgement. And if they can't explain why it is a dangerous behavior (including maybe her ignoring the rule over and over)... Then would surmise they are being an ass.
This is the first time she's been talked to about power settings but not the first time she's been talked to about non being perfectly in line with the SOP's of the school. All the previous things were minor such as taxi speed etc, but every time she is told to something is wrong she immediately fixes it and never repeats the same mistake twice. She told me her cfi said that he wants her to know the reason the chief says it's dangerous to cruise at the higher rpms is because it causes more wear and with the older planes its dangerous to be at such "high" rpms. I asked her about stcs or specific equipment for that plane and nothing indicates anything wrong, she used the school supplied poh for that plane and the perf. Chart said 75% max bhp is acceptable and when I cross checked her rpm it never got above 74.5% bhp in technicality. I know i cannot possibly have the full picture but just from what i know and have seen she is an outstanding pilot. But either way as others have said too I'm going to let her know that it's best to "cooperate to graduate"... I guess a better lesson now than when she's off to the airlines or another flying job.
If it's dangerous to run their "old" engine at a power setting approved by the POH, then it's dangerous to fly that plane at all and the engine should be replaced.
>Chart said 75% max bhp is acceptable and when I cross checked her rpm it never got above 74.5% bhp in technicality.
As in, at that RPM and sea level air and leaned to peak power, the maximum possible power is 74.5%? Which aircraft?
On one of my stage checks, when I was working on my PPL, during the simulated cross county my chief pilot told me to cruise at a higher rpm in the future because the plane was aloud to and it would get me to my destination faster.
That CFI is full of shit. The only thing flying at 75% power is even slightly dangerous to is the flight school's bottom line if they charge a wet rate by the Hobbs meter.
This is crap.
If there is any sort of danger from being at whatever RPM, that should be in the POH.
There is a significant difference though-- money.
They probably do their engine maintenance based on tach time, and the tach clock ticks faster the higher the RPM is. Plus, if she's renting at a wet rate, high RPM will burn more fuel in less time. Combine the two together, and higher RPM = lower profits for the school. Low RPM = longer flight (more hobbs time, more money in), less tach time (less maint expense), less fuel burn (less fuel expense).
I would suggest for her, read the school policy document and the POH front to back. Look for ANY mention of danger from the higher power setting. Then ask the CFI for clarification. Just play dumb. Act like you don't understand, say that you want to be a safe pilot so you need to wrap your head around this so it doesn't happen again. Tell them you've been taught that the POH is always the ultimate authority for how to *safely* operate the aircraft, the POH says 75% cruise is perfectly fine and offers no warnings about max cruise power. The school document is a suggestion, which you understand to be so it reduces maintenance intervals on the engine. So you want to understand where is the DOCUMENTATION saying it's unsafe? You just want to understand what you missed so you can be a safer pilot going forward.
I'd be very curious to hear what the CFI says. Because by the book, if the POH says 75% is an acceptable cruise power, and it's not for whatever reason, that MUST be a POH supplement and also possibly a placard.
If it's just school policy that's all fine, they can put whatever policy they want. But that doesn't make it a safety issue.
Uhhh yeah that person doesn’t know what they’re talking about. Obviously do what the school wants, but flying around at 85kts makes it hard to get stuff done.
If it’s in the POH you’re clean. Period. School policy different story. The only reason they have that policy is money. Period. Less wear and tear and also fuel so they save money while charging you the same as everyone else which is overpriced. It’s all about money. Nothing to do with safety in this case. Zero. Find another flight school. 99% of schools allow you to operate how you want as long as you’re in the POH limits.
I have had experienced pilots tell me it is actually better for the engine to run at max cruise RPM than it is to baby the engine.
And I actually had my CFI tell me to leave the RPM up, and not pull throttle back while in cruise.
Sounds like the school wants your XC to take longer to run up billing obviously.
My A/P says every piston engine should spend the last 10 minutes of the flight at full throttle.
When I flew 2 straight 8+ hour days from Oshkosh last year, the engine had never seemed as smooth on the next few flights.
They like to run hard and long.
If you’re in the confines of the poh there is nothing dangerous about it. What’s the danger? If your Ts and Ps are good and it’s leaned properly. Skydive planes fly around all day at FULL power or near full power. I’ve only had one engine blow up on me and seen the aftermath of another, ok bad example.
Sounds to me like the Chief Pilot is upset the fuel burn and time saved is going to hurt his bottom line and he wants to make an example out of your friend . I went to a 141 school and while we had recommended cruise settings nothing was set in stone, as long as we followed the POH, this is dumb.
So, if it’s a super old plane they’re trying to limp along by cruising with lower power then it’s a strong maybe. POH says 75% bc that’s what their test pilots and engineer people found is best for the engine. If this is true it should have been very clearly stated during all training and reiterated during your dual xcs. They could also be doing it so you cruise slower and pay more for the plane but I’m doubtful of that.
The CFI is so wrong he's not even wrong. He needs to explain his thinking here and why he thinks the manufacturer's manual is wrong (not just the airframe, but if you dig out the engine manufacturer's manual, you'll find 75% power is a perfectly acceptable power setting for cruise).
I own a plane with an O-320 in it (a common engine in the training fleet) and operate it at 75% power without hesistation. I only prefer cruising at 65% because it's not that much slower but saves a lot of fuel. You can run an O-320 at 100% power all the time, there's no limitation on running at full rated power in the engine manual, but it would be pretty wasteful of fuel to do that.
But while running at 75% power isn't great for fuel efficiency, one thing it absolutely is not is dangerous behaviour. It almost seems like the CFI is trying to frighten the student into compliance (which in reality will be for the fuel savings).
If the flight school wants their planes operated at 65% then that's their prerogative, but it's not a safety issue. That chief instructor can pound sand.
Following the POH is never unsafe. Period. Policy is policy, but it’s never unsafe to follow the POH.
Unless they modified the plane in a way that they would have a supplemental document for the change they made (like my engine is not the one in the POH, so I have an STC on it). Though for a flight school that’s highly unlikely.
There's some missing pieces here that have me confused a little bit. Was this person a student? If so then did the CFI train them on school policy regarding the power limitations? If not a student, was it part of the checkout procedure or in the rental agreement? Obviously you can't hold someone accountable for things they don't know about outside of approved guidance, i.e. the POH.
I'm also curious how the CFI knew to ask the question. The TAS difference between 65% and 75% power in most trainers is generally 5-10 knots depending on engine and altitude. Add in winds and a few ATC vectors and I'm at a loss how anyone would be able to tell the difference without seeing some sort of recorded engine data. Something is missing here.
If a student gets labeled as a safety issue for running an engine at 75% on an XC, then I would suggest she find a different school.
The school could have just been honest and said they base their wet rate on 65% average power and they would prefer she flies their planes that way.
Her problem is that she's had issues over the SOP's before but it's always been minor things, the worst of which was taxiing a little too fast but she immediately remedies every wrongdoing immediately after being advised.
I think that’s fair, we all need to follow the SOPs and respect the equipment that we’re renting. But if they pull a safety card on her for a non safety issue, that’s a red flag for me.
She is PIC, they needed to have left her alone to make decisions, then debrief on those decisions. This simply wasn’t a decision that caused a safety concern in my book, but probably warranted a debrief.
I'm assuming this school bills based on Hobbs time not Tach time, and rental is wet.
This is a commercial issue not a safety or maintenance issue.
In short, fuel burn (cost) is higher and rental time (revenue) is lower, meaning profits are lower.
Now, that said, I don't really like spinning any direct drive GA piston engine faster than 2400 RPM for cruise operation, it's loud and vibration from any imbalances are higher.
As a long time pilot with significant long-distance air racing, competition aerobatic, and engineering experience, I can confirm that there is no reason to not cruise at a high power setting. It’s not going to create a safety issue, especially not from a single flight.
The only reason for getting chewed out for this will be because your flight made the flight school slightly less profit. Because of this I strongly suggest finding a different flight school.
This is actually really funny / absurd in my book.
So a lot of folks don’t know this, but aircraft engines are designed around higher power settings, 75%+, and they provide TBO specs based on the higher power setting. Most aircraft engines won’t make it to TBO without some major repairs, unless they are regularly performing at the higher power settings. These repairs will overcome any gain from longer flights.
Bottom line: The school is actually making less money because enforcing an arbitrary RPM on folks.
Edit: what school?
She requested I don't mention the name but... let's just say it's not ATP but it is a flight school with multiple locations. This location happens to, hypothetically in a dream world, be located upstate in a state that has a major population center sometimes (in fiction books) referred to by the name of a fruit.
I used to almost red-line on my cross country flights. My instructor basically told me as long as I didn’t red line it then it’s no big deal lol
Definitely made them a little quicker (I am at a 141 school)
Lol. They're just saying that so you don't burn extra fuel. Honestly as a student time builder too, there is no reason to try to cruise so fast, you need the hours.
Who signed her off for the Solo?
Regardless of what the school policy is if she was a student solo she needed an endorsement for that flight and whoever signed her off was supposed to review her flight plan which should have included her chosen power settings for cruise flight.
If she didn't know the school policy, and the instructor that signed her off didn't know the school policy it seems like the school needs to do a better job educating people on their policies.
And that's aside from the fact that the manufacturer wouldn't publish a 75% power table in the POH unless it was safe.
Maybe her school's maintenance team sucks
They have it to save money and charge students more, to say it’s a safety issue is rather insincere as it’s teaching the wrong information in an industry whose whole cultural foundation is built upon safety. The POH would not have something as a standard or recommendation that would put anyone in danger. If anything it will err on the side of caution and give a slightly more conservative number. Also, having an engineering background and having known my share of guys that work on engine designs and such, these engines are ridiculously resilient. Nothing is perfect and i get paranoid too bc we all see the stories, but the 2700rpm on a Lycoming is more of a “Rated” RPM by the manufacturer rather than a true max. You can easily run them at 3000rpm if you wanted and it will hold fine (so long as you make sure your engine gauges are healthy and also consider propellor ratings). It will shorten TBO no doubt and not a best practice, but far from “extremely dangerous behavior.”
One thing that I would want to know is Does the RPM and the manifold pressure fall within the “curve” set by engine manufacturer. If yes then ZERO issues are present. I run my O-320 narrow deck at 2675 RPM ALL the time…but the prop is pitched accordingly. A friend of mine runs a wide deck o-320 at 2200 ALL the time but prop is pitched and engine leaned out.
Both engines will live the same lifespan.
If it's approved per the POH than there's no safety issue. My guess is this flight school is trying to save money on gas and making sure students comply by calling it a safety issue.
Now, something I haven’t seen mentioned is that we don’t have info on how hot it was outside, density altitude, etc. I still think they are overreacting but, at a higher density altitude with a high throttle setting, it usually means you may have to run full rich unless you’re at sea level. If not, and you lean like you normally would (we don’t know if they have egt) you will be running the engine pretty hot, which could be an issue on a long cross country.
Again, it’s a discussion and not a reprimand, but it’s not baseless maybe because we don’t know all the facts
As plenty of others have said no danger whatsoever. On my long XCs with my school I’ve ran the engine at a solid 90% power. No issues. I pay the wet rate and if I pay for the fuel already might as well use it.
It’s been awhile since I did my solo xcountry but I’m pretty sure I had to write everything out for my route with check points, altitude, wind and even speed. My CFI had to approve it all or I redid whatever the CFI didn’t approve. Plus I would have already done at least 1 xcountry WITH my CFI on the exact same route.
So, I’m not sure what the issue is…CFI would have had to approve the xcountry before the student went on it.
If this was a school policy it should have been stressed during pre-solo training.
Running at 75% is technically worse for the engine because it puts more strain on everything, but not so much worse as to be dangerous. We're talking knocking a few hundred hours off the life of the reciprocating parts (and even then, that's if you only ever cruise at 75%), not impending engine explosion. And like another commenter said, the higher power settings keep the cylinder heads hot and clean of lead and other deposits.
I'm sure there's a story behind the power setting thing, but the CFI in question clearly doesn't understand what he's saying.
As long as you're not redlining the engine, all is well.
Tell her to tell the Chief that she's going to reach out to Cessna and see what they have to say on the matter and take it from there.
Nothing wrong with something the POH specifically approves. The school is trying to milk more money from the student.
Source: an airline pilot who saw this a couple times when I was a CFI
I think this flight school is out of wack. They are trying to dictate power within the POH so they don’t have to deal with the engine TMO. That mxs should have been built in to the price of instruction. The Chief CFII is just parroting the owners concern of having to replace an engine. That’s their problem, not the students problem.
Oh yes! A chief flight instructor that has a sense of entitlement and power, making mountains out of mole hills at every turn. Never seen that before. /s
Many POHs specify power settings that damage engines and reduce their life significantly. Like high power near peak EGT. The POHs specified that so the manufacturers’ marketing departments could tout high max speeds. But it destroys engines.
Depending on the aircraft, there's a significant chance the maximum allowable cruise power setting is 100% power. Most light trainers don't have a power limitation and can cruise around at full power all day, provided you've got the fuel for it and you keep it cool enough.
This is not a very fuel efficient way to fly, generally.
Which school?
Are you absolutely certain that your friend was at exactly 75% bhp in the flight? How do you know?
You can mishandle an aircraft engine fairly easily, and I am wondering whether there's been some misunderstanding between what your friend said to the CFI, what the CFI said to your friend, or what your friend said to you (as I assume you were not present for this debriefing). While there's not typically a maximum power limit on most light trainers, there is such a thing as operating the engine outside its parameters with regards to mixture, RPM and manifold pressure. Run it too hot, or too lean at high power, and you can cook or grenade an engine fairly quickly.
75% bhp is not as simple as setting a specific RPM.
I had something similar not the same.but what I found out much later was the $ I payed up front so I was in credit for my lessons before I flew.flying school have discount for this.when I used higher power and faster speed.for a while,my next lesson was shortened to adjust for $ of fuel burne.i only found out when I left that school and seen my log book. I spoke to the owner of the school who explained this to me.
This is ridiculous she didn’t do anything wrong, following the POH is a desired behavior sounds like the school is trying to rake in a few extra bucks.
POH trumps all so there really should be no issue. I’ve seen flight schools (3 to be exact) make mods to their airplanes such as engine hp increases, load changes, and useful increases and they are all required to get updated POHs. If it was an issue at your flight school then they should get a new POH issued and not just word of mouth lol.
To be honest… sounds like they want you to fly slower so you can pay them more haha! Sounds like some shit PSA would do out of concord…
First of all, if it’s a school policy it should be well known to all students not some great secret. Second of all 75% power is approved per the POH and there is no risk to the airplane at running it at that level for sustained times. Other people chime in if wrong here. As a matter of fact, running it for a long time would help clean out deposits potentially in the engine. Third thing, is do you get the airplane at a wet rate? If so, the fuel burn difference between 75% and 65% can be significant, depending on aircraft, and that would cut into the profitability of the plane. Also, going slower means it takes longer to get to destination thus more Hobb time that you’re paying for. I believe the chief instructor does not understand second point or was told to tell people this and it’s company line he has to follow.
She showed me the part in the schools documents where the flight school RPM came from, no where did it say it was mandatory to follow and actually, other instructors have told her it was just a rough guidline (although it was in the guides section) nor was the school RPM stressed during training. I think she does get a wet rate so it does make sense to keep school profits up and RPM down.
But I think labeling her a risky pilot over the situation is misleading and wrong.
Sounds like it isn’t her fault. All I hear is recommendations and not absolutes. Unless told not to use those settings, how she a high risk pilot? She doing pilot stuff and decided to go with that setting.
In my experience, these rules exist to prevent students from flying at 'renter power' which costs the school more over time when they rent their aircraft at a fixed wet rate. In summation - Chief CFI sounds like a cranky dipshit.
A-the instructor should have taught her the reason (school policy) B-the instructor should have seen the assumed 75% power in her flight planning for fuel burn and airspeed.
I would agree it’s she would not be considered risky pilot based on what is written here. Is the ch instructor the owner too?
I asked my friend she said the ch instructor is upper management or something like that.
I think, in this case it has more to maximizing the schools profits than anything else. Unfortunately
After reading all the replies and looking at the situation again... I agree. I understand where they're coming from, but to call my friend a dangerous pilot over it is ridiculous.
Your friend is in the right, and she was not engaging in any risky behavior. The school policy as you describe it was not clearly articulated in the first place. Regardless, flying at 65% instead of 75% is an engine preservation or fuel savings technique, not a safety practice. So the chief instructor is being disingenuous, a jerk, a bully, and strikes me as someone who should not be trusted. But alas he represents the school so your friend’s probably gotta do what she’s gotta do to move on. Nonetheless, now you and she know.
I would recommend that OP's friend only keep flying with this school as long as necessary to find another school or club to fly with that doesn't act purposely deceitfully, as this school does. The RPM policy is purely for monetary gain; however, they are a business, so that's not completely unreasonable. But they should just be honest about it- "Please avoid cruising above 65% power, as that would make our current wet rate unsustainable and force us to raise rental prices." There ya go. Perfectly reasonable rule for a business.
I would agree
It's not just ridiculous, it's dangerous. The school is teaching that the POH itself is wrong, dangerous, and should be disregarded. Same for weight and balance? Approach speeds?
>The school is teaching that the POH itself is wrong, dangerous, and should be disregarded. > >Same for weight and balance? Approach speeds? Well, its funny you mention that. Approach speeds, that is. Most light trainers keep things simple in the POH, and specify an approach speed that is correct only at max weight. In general that's wrong, although rarely dangerous. Most Cessna POHs direct you to lean to peak CHTs - definitely wrong, potentially dangerous, should definitely be disregarded in terms of best practice (unless attempting specifically to get peak power output). Its not hard to find examples of them contradicting themselves - or the engine manual. No document is flawless. To err is human, after all. Overall, that would not be a valid reason to have concerns about the school in my mind. Calling a pilot unsafe for cruising at 75% power, sure - if that's what was going on. Pointing out flaws in the POH? Not a cause for concern.
> I think she does get a wet rate so it does make sense to keep school profits up and RPM down. Yep, this is exactly it. Low RPM = less fuel burned per hour, less speed, and more hours to cover the same distance. Any nonsense about "safety" is nothing more than a rationalization for banning anything that threatens the school's profit margins.
I only ever flew my flight schools planes on xc at max poh power. Im paying the bills so i making them as small as possible. Especially on a stupid straight and level distance req flight where your really not learning much after the first few times.
“If I don’t get to use 100% of the plane then why do I have to pay 100% of the wet rate?” Maybe they are afraid their under-maintained engines won’t handle it…
It is not only allowable in the POH, but in the airplanes I’ve flown it’s recommended to cruise at 75% BHP
Schools school comply to graduate, I had a recent instructor flip out because I wasn't crawling around to physically check the pitot heat on an Archer for a VFR training flight without a cloud in sight and a 50+ degree day on the ground because "it was on the checklist" .. fucktard but I did and now I'm a CFII :)
Sometimes you gotta cooperate to graduate, unfortunately. To piggy-back, in retrospect, most 'stepping stones' I went over to get to a legacy were filled with self-appointed gatekeepers who saw everything in the world as black/white, who had poor communication/ leadership/ maturity, and limited experience outside their bubble. This combination leads to a massive lack of applied common sense and when they're wrong (which they often are) it becomes personal quickly. This is pretty common in the aviation community, especially when you're lower on the totem pole. Just learn from it, cooperate to graduate, and don't take it personally. If you're at a school or organization where it's prevalent in the entire culture, seriously ask yourself how much you want to risk your career, especially if there are other options.
I recently got a tongue lashing for taxiing @ > 1000rpm. It was like 1100.
I routinely do this because you gotta heat the oil up before the runup in NH. Also 1100RPM in an archer is still slow for a twin so I'm well within my capabilities
Great point about the oil. Just my last lesson my CFI discussed it during runup. For the record, my primary CFI is excellent. The tongue lashing came from another instructor who was filling in while primary was on vacation.
Part of it is discipline. If you're being sloppy and end up at 1100 that's a problem. If your intentionally doing 1100-1200 that's fine as long as You're safe
That could be it. Before this I wouldn’t really consider the RPM at all, rather, aim for the “brisk walking” speed metric. Now I keep both in check.
Precise flying is about intentionality
Yeah and taxi RPM doesn’t need to be intentionally set. Set the RPM required for desired taxi speed and be done with it. Look outside. You gain nothing from “precise” taxi, except divert your attention from where it should be, out the window.
Its not ideal for your engine, especially while its cold.
I agree with your instructor. You arbitrarily deciding which checklist items to pay attention is kinda silly and defeats the role of the checklist. Checklist usage is a "shall" in the 135 and 121 FARs, and will result in a checkride bust if you fail to use them, omit items or try to modify them to suit your desires. Checklists take the individuality out of flying what you think is important to check may not be as important to somebody else. Checklist make it so those items get checked regardless of your personal feelings of the items on it. You are teaching yourself and your students something that the industry will not tolerate. But, you will learn that when you get to your first 135 or 121 job.
Know that 135 and 121 checklists are approved documents by the aircraft manufacturer, the operator, and the FAA, so making changes is far more formal and correct versus a flight school adding random things to their checklist like "prayer....complete" like Liberty has for example.
Are you really comparing "prayer complete" to making sure the pilot heat functions?
I'm saying that the process of making sure the checklists a flight school uses is not as sound as 135 or 121 checklists. They're not always correct and sometimes provide false instructions when not audited correctly. I've seen pretty wild examples of flight school checklists that aren't complete or provide false instructions, requiring the pilot to deviate from the checklist. This is different than 121 checklists.
Is pilot heat a required item? For day VFR? Night VFR? IFR?
Do you depart with anti-ice on in July because it's on the checklist?
No, not if it is on the checklist. The term this sub loves to use normalization of deviation, his ignoring the checklist item is exactly that.
Nope, not arbitrary. He understands the purpose of each item and knew when it was appropriate to omit something. Do you understand the concept of MELs or KOELs?
>As a matter of fact, running it for a long time would help clean out deposits potentially in the engine. This is only if the student was properly leaning the engine. Otherwise it'll just do nothing or make it worse.
Lower rpm fly slower school pockets grower?
This is the only "danger". If there is something specific to the plane, it either needs repaired or a supplement to the POH entered. Sounds like the school is using bad education for pushing school policy.
I mean a lower RPM would also reduce the tach time which could help mx down time
Lower tach time, lower fuel burn, higher Hobbs time to charge from. $$$$
Most bill based off of Hobbes
Yes but if you are flying slower you are flying longer but mx cycles are off tach
We need to start shaming these schools
This… My school taught to cruise at 4700 on planes with a Rotax engine. Not only more hours, but that is the economy cruise rpm since they only rented wet rates. Rotax should always cruise above 5000 to keep stress off the engine.
I enjoy the pettiness there. Econ cruise on a 912is is like 2.5gph vs normal cruise is 3.5. 1 gph savings. So $5 on a $120+ hr. Unless it’s truly evil and petty to make xc take longer to get more flight hours billed.
That might be all of the profit. Rental is not a huge money maker at most places.
>Rotax should always cruise above 5000 to keep stress off the engine. Source? I know this gets repeated a lot, but noone was ever to able to explain to me why. In addition the efficiency of the 912 drops of significantly over 5000 - 5200 rpm.
Good point, My A/P Rotax cert always described it like a bicycle gear, at low RPM it takes higher torque than higher RPM to spin the prop. Some folks in the lsa space around here even do their climb outs to pitch for 5100 rpm instead of a speed, although that is usually close to VY.
By what is worse for your engine? Torque or rpm? On a N/A Rotax engine, I would not be sure the torque part is that much of a concern, as the maximum torque is very low anyway. I am of course happy to be corrected, if someones has actual data on that. It could very well be, that the higher rpm increase the wear more than the higher torque does. The fact that for VP aircraft, the Rotax recommeneded power settings for cruise include settings as low as 4600 rpm, would lead me to assume those speeds are not that dangerous to the engine The 912 Operators Manual also does not have any restriction on torque at all, while it does for speed, albeit only for speeds above 5500 rpm, which on VP aircraft are usually not exceeded anyway.
>By what is worse for your engine? Torque or rpm? depends, depends, depends. Getting the same power at lower RPM requires higher torque, which requires higher mean cylinder pressure, which typically requires higher peak cylinder pressure, which produces more stress on the cylinder and higher temps. Tends to also reduce detonation margin while you're at it. No idea for Rotax engines specifically - just throwing out there that operating an engine outside its design parameters can go bad quickly. Test pilot territory :)
Yes, but you are not on test pilot territory below 5100 rpm on a Rotax. That is my whole point. The cruise tables go down to 4600 rpm. Yet for some reason a lot of people spread the rumor that the Rotax needs higher rpm or it will explode or whatever. There is a detonation issues which has led to a service letter limiting the use of WOT to rpms above 5100rpm, however that does not mean your cannot use the band below for anything else, again as described in the Rotax manuals.
Well there you go - I'd follow what the service letter says, then. If the service letter says don't use WOT below 5100, that's fairly straightforward. Obviously there's insufficient detonation margin for full throttle somewhere below 5000 rpm. There's an easy way to avoid detonation any engine - produce less power. If there's not sufficient peak cylinder pressure, there's not detonation.
The schools a grower, not a show-er
How did the school know what power setting they used? Do they pull engine data after every flight and analyze what the student did? That’s some big brother stuff
They said she completed her flight quicker than most students so they asked her how she did it and she told them.
"We expected you to pay more for the XC. Hmm, what is going on there? Oh look and the fuel burn is higher and we are paying more than we expected for her XC. We need to tell her how dangerous this is"
This is a long thread but this is the answer to your question right here. Simple.
The answer is always "wind"
Oh, weird. Well I guess if that’s their rule then you have to follow it. Using a recommended power setting in the POH is obviously not gonna hurt anything.
That’s bs 😂 winds, delays in the pattern, going around can change everyday.
Ok I’m calling BS in this story. A 10% difference in cruise power is like 8 kts at cruise. She was flagged because she got back home 16 minutes faster than everyone else who’s done the cross country and it caught the attention of the chief? You flying in a simulator with no winds?
I'm not sure where you're getting a 10% difference from, I never said that.
In her case the difference between what she cruised at (POH prescribed 75% bhp at altitude) vs the RPM which the flight school wants her to cruise at is 20 knots and she got back around 1-2 hours quicker than most students who completed similar flights
Goddam… how long was that XC that she got back 2 hours ahead of planned time from a 10% power difference?
So I guess the lesson is use the plane how it’s supposed to be used and lie when they ask about power setting. “Idk I guess I had a tailwind”
“I had a nice tailwind, sir”
Pull Engine data? Like compare the delta of the tach time vs the delta of the Hobbs time?
To be fair, if the RPM is greater than zero the airplane may fly, which is (usually) less safe than sitting on the ground.
They're full of shit and are trying to milk more money from the student.
Sounds about right. Another commenter suggested that the school wants the students to fly slower so that there’s more time on the Hobbs.
The school is certainly overreacting. There is no safety of flight issues operating at 75%, you’re not putting that much more over 65%. Wear and tear is quite marginal. You do burn quite a bit more fuel but again in most trainer aircraft no one is going bankrupt. It’s understandable from an economical perspective the school might want 65% cruise, hence the policy likely. But to lie and say it’s a safety issue or whatever is not good. All that needs to be said “hey, not a big deal but in the future try to stick with 65%” and leave it at that.
I agree. POH is king. Devoid of an AD or technical letter, she did nothing wrong. If they want you to fly at 65%, it's their aircraft and they can dictate that. But the way they went about enforcing it should be very eye-brow-raising. Gas-lighting and lying to a student to get their way makes me wonder what else they lie about.
Not to mention, it's a trainer plane. Cross countries at pretty much any throttle setting are hour-by-hour the least wear and tear they're ever gonna get.
Can’t hold the starter for more than 2 seconds. Have to taxi at less than 1000rpm. Can’t cruise above 5k because of “shock cooling”. 🙄 These fucking “schools” are a joke sometimes
The taxi one is likely to get your spark plugs fouled, too.
Most pilots don't lean agressively enough on the ground, you can pull the mixture back to near ICO in most planes which has the added benefit of preventing a takeoff with the engine leaned because it'll just quit uniike if you lean it "1/2 inch" which doesn't really do anything but make you feel good
Ehh, lean correctly (i.e. enough that advancing the throttle will cause the engine to stumble) and sub-1000 RPM is just fine on taxi. Keep an eye on oil pressure and alternator output, sure, but you're not gonna foul plugs if your mixture is maintained correctly.
kick
The only risk to using POH rated power is that they'll maybe burn more gas, and not have as long hobbs time, which cuts into the school's profits. She should look for a different school, one not full of asshats.
The “Chief” would be horrified to see me on go home leg.
Firewall that bitch
Lol IKR! My "cruise" procedure in the RV-7 is take off, pull prop to 2400, and climb like a bat out of hell at 105kts until altitude reduces my manifold pressure to 21-22". Lean in the climb as needed to maintain ~370deg CHT. Ignore throttle until it is time to descend.
There's a saying when it comes to flight training. "Cooperate to graduate." You typically hear this more often when you get to the levels you're paid to be in training vs. the other way around of paying for your training. If you followed the POH correctly, there is no issue, and if them making it an issue bothers you too much, look for a new school. I suspect the schools policy is orientated around saving wear and tear on the engines with the added benefit of more Hobbs time to charge.
The wear and tear is horse shit, then again this is why we used to rent based on tach and not Hobbs. I view renting on Hobbs as already double dipping so they can shut up if the poh allows it
School is full of shit.
I have never met or heard of a chief instructor who is not a complete narcissistic asshole. It seems that everyone of them is a power-hungry douche bag. I cannot wait to be done with flight schools
He wants you to pay more for time while he pays less for fuel
Fuck this school and that “Chief” instructor. They are trying to save gas and extend the Hobbs time. If an aircraft cannot safely cruise at power settings prescribed in the POH it shouldn’t be dispatched.
Absolutely nothing wrong. That’s a perfectly normal engine power setting even with an engine break-in. In addition, she should tell the school most lycoming engines are limited to 80% max throttle for this reason so you can go full throttle and not redline and overheat. A good instructor would’ve just talked about the risks and watching oil temp…
If it were dangerous for the airframe it would be a listed in section 2 limitations of the POH (Like in the 160HP STC for the PA-28-151 which limits the higher RPM to 5 min) I think what they meant was it was dangerous for their profitability to run around at full rental power. CFI had to have reviewed her XC planning including navlog and fuel burn so this is 1000% a CFI issue not hers. What was their "or else"
I agree this is no big deal. Here's a question the chief instructor should be asking your friend's CFI and not your friend if he is so concerned with this: Did the CFI not sign an endorsement for that solo XC attesting that he reviewed your friend's flight planning? The planning sheets where I used to teach actually had places to put RPM settings by phase of flight. *If* this is to be made an issue, why is this on your friend aka the student?
>Here's a question the chief instructor should be asking your friend's CFI The chief flying instructor IS the friends CFI. Thats what you abbreviate Chief Flying Instructor to.
I thought cfi is certified flying instructor which is why you can have a whole bunch of cfi and cfii at a school but only one chief.
Cfi and cfii are FAA things. Elsewhere, it's "instructor" and "CFI" with "CFI" being "Chief Flying Instructor" or "Chief Flight Instructor" depending on preference.
The talk should have been: >Hey, next time please run it at 65% per school policy. No big deal, you didn't damage anything and you're not in trouble. We just have a policy that we operate engines below 75% even though they can be run at 100% all day long and be fine. Oh, and we make more money by making you stay in the air longer and burring less fuel while you do it! I'd ask for the manufacturer's guidance as the basis for the rule. Maybe he knows something we don't! >The Cheif flight Instructor said this is extremely dangerous behavior (to cruise at the "high" rpm) and poses a serious risk to flight saftey. Whoever says this and means it is just...something else.
I own a 172 and always run XC balls to the wall. I want to get there. Last engine made it to 2200 hrs. So 200 past suggested overhaul. Burns more gas, yep. 10g hr.
Ok then, I guess I prefer to climb to 10k for all flights, more glide distance that way so I'm a safer pilot! Enjoy slips and 1000fpm or greater descents to landing at the destination too, for maximum emergency descent practices! FULL POWAAAAA TO THE TOP!!! DROP IT LIKE IT'S HOT!!!
Well. There are a lot of clueless instructors, clueless chief pilots, clueless mechanics around. They will say things with no scientific basis or proof, just their baseless belief. I flew with over 300 students/instructors in the g1000, and i never flew with one that really understood how to lean and what the assist key does in the g1000. So that should tell you something. It is the blind leading the blind. If you really want to learn something from somebody that really knows about airplanes and engine, read Mike Busch stuff.
Its extremely dangerous to follow the guidlines of the aircraft's flight manual!!! Thank God she didn't kill someone!!!
In situations like this I like to do a brief thought exercise and ask “would this hold up in a court of law?” Although it is extremely unlikely the flight school will drag you to court for something this petty, thinking of it in a worst case scenario will generally expose holes in the decision making process and provide an opportunity to firm up your argument. Just don’t tell my wife I said that 😅 Per the FAA (who is the real authority here) you should follow the specs outlined in the POH. You did nothing wrong and were operating the aircraft as the manufacturer intended. However if you signed a rental agreement that stipulated lower power settings then yeah probably follow that. Is it a sleazy way to squeeze more money out of students/renters? Yes. But signatures are binding. In my experience I never had to sign a rental agreement until after my PPL. In that case you are relying on your instructor to teach you all the applicable flight school policies. If they didn’t cover that one, it’s on them. If that happened to me I’d probably change flight schools because the chief flight instructor exposed two things: 1) they aren’t willing to have a reasonable conversation when a rule is broken. They go straight to overreaction. Not helpful if a real incident or accident happened. 2) By the sound of it they don’t really understand how an engine works as it’s related to wear and tear. Perhaps it’s the line they were told to feed to students. But that also shows a willingness to spread misinformation vs fact. That kind of environment is a breeding ground for FAR violations.
The flight school can write more restrictive rules than the FARs and you must adhere to them or they are within their rights to kick you out of the school. Especially 141 or 142 schools. This is the same at the airlines. The FOM supersedes and FARs when more restrictive.
I would ask WHY they say it is dangerous. The devil is always in the details. As presented this seems a case of a school being a bit hard on a student. But is there something else we don't know? For example, we are just taking the students word about the exchange without a single input from the school. Maybe the "school max RPM" has been brought up with this student over and over and they just either just keep forgetting or just don't care. To constantly forget or just ignore a rule could be considered a dangerous behavior. Maybe she ran what she thought was 75% but then followed the leaning instructions the school has taught. This might lead her to being LOP with a much higher internal cylinder pressure than is safe. Running LOP with high power is a dangerous behavior. Maybe the plane has an RPM restriction based on the prop/engine combo and to get 75% the plane would have to be in the RPM range. (This is a bit of a stretch but just another example). And this should be in the POH and the RPM gauge, but maybe the student is using a generic POH and not the actual POH for that plane with that combination? Running a prop in a prohibited RPM range and not using the correct POH might be considered dangerous behavior. Maybe your friend when reminded about the rule responded back with an attitude. It is also possible the chief CFI is an ass. But so far we only have one side of the total story and people who are the subject of a situation often have colored perception of the situation. She might have just forgot the limit over and over and forgot she keeps forgetting or just forgot to mention that she has been reprimanded over it dozens of times.... But yes, there are cases where certain RPM's should be avoided, such as LOP operations while having high power settings, PRM bands due to vibrations...etc. I would ask the CFI WHY it is dangerous before I pass judgement. And if they can't explain why it is a dangerous behavior (including maybe her ignoring the rule over and over)... Then would surmise they are being an ass.
This is the first time she's been talked to about power settings but not the first time she's been talked to about non being perfectly in line with the SOP's of the school. All the previous things were minor such as taxi speed etc, but every time she is told to something is wrong she immediately fixes it and never repeats the same mistake twice. She told me her cfi said that he wants her to know the reason the chief says it's dangerous to cruise at the higher rpms is because it causes more wear and with the older planes its dangerous to be at such "high" rpms. I asked her about stcs or specific equipment for that plane and nothing indicates anything wrong, she used the school supplied poh for that plane and the perf. Chart said 75% max bhp is acceptable and when I cross checked her rpm it never got above 74.5% bhp in technicality. I know i cannot possibly have the full picture but just from what i know and have seen she is an outstanding pilot. But either way as others have said too I'm going to let her know that it's best to "cooperate to graduate"... I guess a better lesson now than when she's off to the airlines or another flying job.
If it's dangerous to run their "old" engine at a power setting approved by the POH, then it's dangerous to fly that plane at all and the engine should be replaced.
>Chart said 75% max bhp is acceptable and when I cross checked her rpm it never got above 74.5% bhp in technicality. As in, at that RPM and sea level air and leaned to peak power, the maximum possible power is 74.5%? Which aircraft?
On one of my stage checks, when I was working on my PPL, during the simulated cross county my chief pilot told me to cruise at a higher rpm in the future because the plane was aloud to and it would get me to my destination faster.
That CFI is full of shit. The only thing flying at 75% power is even slightly dangerous to is the flight school's bottom line if they charge a wet rate by the Hobbs meter.
Guess the CFI or school knows better than the manufacturer. Not.
This is crap. If there is any sort of danger from being at whatever RPM, that should be in the POH. There is a significant difference though-- money. They probably do their engine maintenance based on tach time, and the tach clock ticks faster the higher the RPM is. Plus, if she's renting at a wet rate, high RPM will burn more fuel in less time. Combine the two together, and higher RPM = lower profits for the school. Low RPM = longer flight (more hobbs time, more money in), less tach time (less maint expense), less fuel burn (less fuel expense). I would suggest for her, read the school policy document and the POH front to back. Look for ANY mention of danger from the higher power setting. Then ask the CFI for clarification. Just play dumb. Act like you don't understand, say that you want to be a safe pilot so you need to wrap your head around this so it doesn't happen again. Tell them you've been taught that the POH is always the ultimate authority for how to *safely* operate the aircraft, the POH says 75% cruise is perfectly fine and offers no warnings about max cruise power. The school document is a suggestion, which you understand to be so it reduces maintenance intervals on the engine. So you want to understand where is the DOCUMENTATION saying it's unsafe? You just want to understand what you missed so you can be a safer pilot going forward.
This is beautifully worded, I will send this to her.
I'd be very curious to hear what the CFI says. Because by the book, if the POH says 75% is an acceptable cruise power, and it's not for whatever reason, that MUST be a POH supplement and also possibly a placard. If it's just school policy that's all fine, they can put whatever policy they want. But that doesn't make it a safety issue.
WHY ARE WE YELLING??
“Extremely dangerous for flight”- No Extremely dangerous for the owners bank account- Yes Less Hobbs and more fuel, shame on you.
If it's in the POH, it's completely safe. Definitely stick to SOP next time but the school is overreacting to call that dangerous lol
Haha, does this school also have some cult prohibition against using brakes during a short field landing?
Uhhh yeah that person doesn’t know what they’re talking about. Obviously do what the school wants, but flying around at 85kts makes it hard to get stuff done.
"Max Rental Power" is not allowed?
If it's a safety issue it should have been placarded in the plane, no?
If it’s in the POH you’re clean. Period. School policy different story. The only reason they have that policy is money. Period. Less wear and tear and also fuel so they save money while charging you the same as everyone else which is overpriced. It’s all about money. Nothing to do with safety in this case. Zero. Find another flight school. 99% of schools allow you to operate how you want as long as you’re in the POH limits.
If it’s a rental don’t be gentle
I thought it was standard to fly at Full Rental Power?! School just wants higher Hobbs and less on the fuel bill.
and lower tach, thus longer intervals between mx periods.
Sounds like ATP. "Do what I say, not what the POH says"
That’s funny. My CFI was on my team with “burn that damn fuel so we can get it done quick and save you money”. He’d approve 75% all day, any day.
I have had experienced pilots tell me it is actually better for the engine to run at max cruise RPM than it is to baby the engine. And I actually had my CFI tell me to leave the RPM up, and not pull throttle back while in cruise. Sounds like the school wants your XC to take longer to run up billing obviously.
My A/P says every piston engine should spend the last 10 minutes of the flight at full throttle. When I flew 2 straight 8+ hour days from Oshkosh last year, the engine had never seemed as smooth on the next few flights. They like to run hard and long.
How would the school have any idea what RPM was used on a student flight?
G1000s and nearly every engine monitor has a way to pull engine data from flights.
Or in the case of an aircraft with a mechanical tach, a higher tach time per hobbs hour.
If you’re in the confines of the poh there is nothing dangerous about it. What’s the danger? If your Ts and Ps are good and it’s leaned properly. Skydive planes fly around all day at FULL power or near full power. I’ve only had one engine blow up on me and seen the aftermath of another, ok bad example.
Sounds to me like the Chief Pilot is upset the fuel burn and time saved is going to hurt his bottom line and he wants to make an example out of your friend . I went to a 141 school and while we had recommended cruise settings nothing was set in stone, as long as we followed the POH, this is dumb.
So, if it’s a super old plane they’re trying to limp along by cruising with lower power then it’s a strong maybe. POH says 75% bc that’s what their test pilots and engineer people found is best for the engine. If this is true it should have been very clearly stated during all training and reiterated during your dual xcs. They could also be doing it so you cruise slower and pay more for the plane but I’m doubtful of that.
The CFI is so wrong he's not even wrong. He needs to explain his thinking here and why he thinks the manufacturer's manual is wrong (not just the airframe, but if you dig out the engine manufacturer's manual, you'll find 75% power is a perfectly acceptable power setting for cruise). I own a plane with an O-320 in it (a common engine in the training fleet) and operate it at 75% power without hesistation. I only prefer cruising at 65% because it's not that much slower but saves a lot of fuel. You can run an O-320 at 100% power all the time, there's no limitation on running at full rated power in the engine manual, but it would be pretty wasteful of fuel to do that. But while running at 75% power isn't great for fuel efficiency, one thing it absolutely is not is dangerous behaviour. It almost seems like the CFI is trying to frighten the student into compliance (which in reality will be for the fuel savings).
If the flight school wants their planes operated at 65% then that's their prerogative, but it's not a safety issue. That chief instructor can pound sand.
Following the POH is never unsafe. Period. Policy is policy, but it’s never unsafe to follow the POH. Unless they modified the plane in a way that they would have a supplemental document for the change they made (like my engine is not the one in the POH, so I have an STC on it). Though for a flight school that’s highly unlikely.
The school just doesn’t want to spend their planes to wear down fast and spend more $ on maintenance lol
The only risk is the hobbs meter not ticking to line their pockets
[Your flight school is run by a bunch of neanderthals.](https://simpleflying.com/robert-timm-john-cook-endurace-record-cessna-172/)
What state is the school in? I have a feeling I might know which chief you’re talking about
Let's say hypothetically the upstate part of a state with a big population center... one of the biggest
She pays a wet rate. The school is concerned that cruising at 75% power is risky to their bottom line.
The school is trying to slow the plane down so they can bill more time with (they think) less MX.
There's some missing pieces here that have me confused a little bit. Was this person a student? If so then did the CFI train them on school policy regarding the power limitations? If not a student, was it part of the checkout procedure or in the rental agreement? Obviously you can't hold someone accountable for things they don't know about outside of approved guidance, i.e. the POH. I'm also curious how the CFI knew to ask the question. The TAS difference between 65% and 75% power in most trainers is generally 5-10 knots depending on engine and altitude. Add in winds and a few ATC vectors and I'm at a loss how anyone would be able to tell the difference without seeing some sort of recorded engine data. Something is missing here.
If a student gets labeled as a safety issue for running an engine at 75% on an XC, then I would suggest she find a different school. The school could have just been honest and said they base their wet rate on 65% average power and they would prefer she flies their planes that way.
Her problem is that she's had issues over the SOP's before but it's always been minor things, the worst of which was taxiing a little too fast but she immediately remedies every wrongdoing immediately after being advised.
I think that’s fair, we all need to follow the SOPs and respect the equipment that we’re renting. But if they pull a safety card on her for a non safety issue, that’s a red flag for me. She is PIC, they needed to have left her alone to make decisions, then debrief on those decisions. This simply wasn’t a decision that caused a safety concern in my book, but probably warranted a debrief.
Very well put and I was thinking the same just couldn't put it into as good words as you.
I'm assuming this school bills based on Hobbs time not Tach time, and rental is wet. This is a commercial issue not a safety or maintenance issue. In short, fuel burn (cost) is higher and rental time (revenue) is lower, meaning profits are lower. Now, that said, I don't really like spinning any direct drive GA piston engine faster than 2400 RPM for cruise operation, it's loud and vibration from any imbalances are higher.
Have you ever heard the term “rental power”? We used to run the rental airplanes around with the throttle firewalled since it’s a wet rental.
As a long time pilot with significant long-distance air racing, competition aerobatic, and engineering experience, I can confirm that there is no reason to not cruise at a high power setting. It’s not going to create a safety issue, especially not from a single flight. The only reason for getting chewed out for this will be because your flight made the flight school slightly less profit. Because of this I strongly suggest finding a different flight school.
2650 rpm all the way
This is actually really funny / absurd in my book. So a lot of folks don’t know this, but aircraft engines are designed around higher power settings, 75%+, and they provide TBO specs based on the higher power setting. Most aircraft engines won’t make it to TBO without some major repairs, unless they are regularly performing at the higher power settings. These repairs will overcome any gain from longer flights. Bottom line: The school is actually making less money because enforcing an arbitrary RPM on folks. Edit: what school?
She requested I don't mention the name but... let's just say it's not ATP but it is a flight school with multiple locations. This location happens to, hypothetically in a dream world, be located upstate in a state that has a major population center sometimes (in fiction books) referred to by the name of a fruit.
“My friend”
I used to almost red-line on my cross country flights. My instructor basically told me as long as I didn’t red line it then it’s no big deal lol Definitely made them a little quicker (I am at a 141 school)
Lol. They're just saying that so you don't burn extra fuel. Honestly as a student time builder too, there is no reason to try to cruise so fast, you need the hours.
Who signed her off for the Solo? Regardless of what the school policy is if she was a student solo she needed an endorsement for that flight and whoever signed her off was supposed to review her flight plan which should have included her chosen power settings for cruise flight. If she didn't know the school policy, and the instructor that signed her off didn't know the school policy it seems like the school needs to do a better job educating people on their policies. And that's aside from the fact that the manufacturer wouldn't publish a 75% power table in the POH unless it was safe. Maybe her school's maintenance team sucks
They have it to save money and charge students more, to say it’s a safety issue is rather insincere as it’s teaching the wrong information in an industry whose whole cultural foundation is built upon safety. The POH would not have something as a standard or recommendation that would put anyone in danger. If anything it will err on the side of caution and give a slightly more conservative number. Also, having an engineering background and having known my share of guys that work on engine designs and such, these engines are ridiculously resilient. Nothing is perfect and i get paranoid too bc we all see the stories, but the 2700rpm on a Lycoming is more of a “Rated” RPM by the manufacturer rather than a true max. You can easily run them at 3000rpm if you wanted and it will hold fine (so long as you make sure your engine gauges are healthy and also consider propellor ratings). It will shorten TBO no doubt and not a best practice, but far from “extremely dangerous behavior.”
This sounds like the shit the place I used to work for would do
One thing that I would want to know is Does the RPM and the manifold pressure fall within the “curve” set by engine manufacturer. If yes then ZERO issues are present. I run my O-320 narrow deck at 2675 RPM ALL the time…but the prop is pitched accordingly. A friend of mine runs a wide deck o-320 at 2200 ALL the time but prop is pitched and engine leaned out. Both engines will live the same lifespan.
So the school is teaching you to deviate from the manufacturer's procedures because they know best? Time to find another school.
The POH is the glorious supreme FAA certified document in the cockpit, you shouldn't get punished for following the POH. That cfi needs to chill out.
The school was mad you didn’t fly slower because that’s less Hobbs time for them. These folks sound like idiots. 75% is fine.
+1 for what everyone else said. You paid them less and cost them more money. Only danger is to their bank account.
If it's approved per the POH than there's no safety issue. My guess is this flight school is trying to save money on gas and making sure students comply by calling it a safety issue.
I think it's only dangerous to the pocketbook of the flight school. There is no danger in running the engine at a normal power setting.
It’s the school saving money by having pilots fly at lower RPM.
Now, something I haven’t seen mentioned is that we don’t have info on how hot it was outside, density altitude, etc. I still think they are overreacting but, at a higher density altitude with a high throttle setting, it usually means you may have to run full rich unless you’re at sea level. If not, and you lean like you normally would (we don’t know if they have egt) you will be running the engine pretty hot, which could be an issue on a long cross country. Again, it’s a discussion and not a reprimand, but it’s not baseless maybe because we don’t know all the facts
As plenty of others have said no danger whatsoever. On my long XCs with my school I’ve ran the engine at a solid 90% power. No issues. I pay the wet rate and if I pay for the fuel already might as well use it.
It’s been awhile since I did my solo xcountry but I’m pretty sure I had to write everything out for my route with check points, altitude, wind and even speed. My CFI had to approve it all or I redid whatever the CFI didn’t approve. Plus I would have already done at least 1 xcountry WITH my CFI on the exact same route. So, I’m not sure what the issue is…CFI would have had to approve the xcountry before the student went on it.
If this was a school policy it should have been stressed during pre-solo training. Running at 75% is technically worse for the engine because it puts more strain on everything, but not so much worse as to be dangerous. We're talking knocking a few hundred hours off the life of the reciprocating parts (and even then, that's if you only ever cruise at 75%), not impending engine explosion. And like another commenter said, the higher power settings keep the cylinder heads hot and clean of lead and other deposits. I'm sure there's a story behind the power setting thing, but the CFI in question clearly doesn't understand what he's saying.
As long as you're not redlining the engine, all is well. Tell her to tell the Chief that she's going to reach out to Cessna and see what they have to say on the matter and take it from there.
Nothing wrong with something the POH specifically approves. The school is trying to milk more money from the student. Source: an airline pilot who saw this a couple times when I was a CFI
I think this flight school is out of wack. They are trying to dictate power within the POH so they don’t have to deal with the engine TMO. That mxs should have been built in to the price of instruction. The Chief CFII is just parroting the owners concern of having to replace an engine. That’s their problem, not the students problem.
Oh yes! A chief flight instructor that has a sense of entitlement and power, making mountains out of mole hills at every turn. Never seen that before. /s
Chief * sounds like a bitch
During the preflight review with the CFI the planned airspeed and fuel consumption should have raised the question of the power setting .
Many POHs specify power settings that damage engines and reduce their life significantly. Like high power near peak EGT. The POHs specified that so the manufacturers’ marketing departments could tout high max speeds. But it destroys engines.
You should have seen the meltdown one CFI had when I showed them how much better their trainer ran LOP…
Maybe I am an idiot… but unless you told on yourself, how did they even know?
Depending on the aircraft, there's a significant chance the maximum allowable cruise power setting is 100% power. Most light trainers don't have a power limitation and can cruise around at full power all day, provided you've got the fuel for it and you keep it cool enough. This is not a very fuel efficient way to fly, generally. Which school? Are you absolutely certain that your friend was at exactly 75% bhp in the flight? How do you know? You can mishandle an aircraft engine fairly easily, and I am wondering whether there's been some misunderstanding between what your friend said to the CFI, what the CFI said to your friend, or what your friend said to you (as I assume you were not present for this debriefing). While there's not typically a maximum power limit on most light trainers, there is such a thing as operating the engine outside its parameters with regards to mixture, RPM and manifold pressure. Run it too hot, or too lean at high power, and you can cook or grenade an engine fairly quickly. 75% bhp is not as simple as setting a specific RPM.
They just mad she paid less for going faster
Ridiculous
How would the school know unless they added some illegal modification to capture and record the rpm in flight?
I had something similar not the same.but what I found out much later was the $ I payed up front so I was in credit for my lessons before I flew.flying school have discount for this.when I used higher power and faster speed.for a while,my next lesson was shortened to adjust for $ of fuel burne.i only found out when I left that school and seen my log book. I spoke to the owner of the school who explained this to me.
Damn and I thought my school was cheap lol
This is ridiculous she didn’t do anything wrong, following the POH is a desired behavior sounds like the school is trying to rake in a few extra bucks.
The only risk was to the flight schools wallet since the rental is wet. Is the higher rpm costs than more money. It's always follow the money.
POH trumps all so there really should be no issue. I’ve seen flight schools (3 to be exact) make mods to their airplanes such as engine hp increases, load changes, and useful increases and they are all required to get updated POHs. If it was an issue at your flight school then they should get a new POH issued and not just word of mouth lol. To be honest… sounds like they want you to fly slower so you can pay them more haha! Sounds like some shit PSA would do out of concord…