What is the reasons most piston engines fail in flight
Posted by DontPanicHangInThere@reddit | flying | View on Reddit | 253 comments
300hr cfi rant . Almost daily I come across another story or atc recording of a piston engine usually a Cherokee or Cessna having an emergency engine failure causing them to land off field …..if they’re lucky.
What are 100 hr maintenance checks missing? Is it just dumb luck? Are there signs you guys look for during run up besides obvious roughness or mag drops outside of the limits etc? Are there certain personal minimums you guys use on top required airworthiness for maintenance for planes being used for rent or hire?
I follow a lot of aviation pages online so maybe I’m just over exposed to all these engine failures but none of them seem to ever post a reason for the failure. I started flying a few months before the aopa guy who reviewed all these emergencies went down shortly after takeoff in a newer Cessna and was killed. That had always really stuck with me. If it can happen to the guy who dedicated the end of his professional career to keeping people safe it can really happen to anyone, anytime.
To piston engines just suck, what’s the deal?
aviatorboatcapn@reddit
Keep in mind, a perfectly good engine that quits due to fuel exhaustion is listed as “engine failure” in NTSB data points. So, a misnomer really.
Final_Winter7524@reddit
Most piston engines do not fail in flight.
Granite_burner@reddit
Mine did.
Final_Winter7524@reddit
Well, I‘m glad you’re still here to comment.
Granite_burner@reddit
Me too. Did everything right, and got lucky.
taggingtechnician@reddit
Gasoline was and still is a bad fuel choice, and it exacerbates the inherent inefficiencies of reciprocating engines. I am both a pilot and a boat captain, and it struck me years ago how in the maritime industry they take huge reciprocating engines and "de-rate" the output with the intention of extending longevity. In many cases a marine engine has three categories of rated horsepower output based on the demand requirements; here is a short explanation Diesel Marine Engine Ratings | MyMarineTracker In many ships, 100% throttle usually means 80% throttle, with the option to use 120% throttle for 5 minutes (or some other time limit)
For turbine aircraft, the crew monitors the TGT/EGT as a way of measuring output and extending longevity. As I am flying my helicopter, the TGT/EGT instruments have marks indicating certain limits that should not be exceeded, or if exceeded must be logged in the maintenance log (in some situations additional inspections are required post-flight). The pilot must calculate the weight limits that avoid exceeding these TGT/EGT limits during the entire flight, and restrict flight maneuvers to also avoid exceeding the limits.
None of this is addressed in GA pilot training regarding smaller gas-powered reciprocating engines, yet.
This is part of what is driving the manufacture of small turbine engines for GA aircraft (and also electric power).
Here is a bit of good news: 1) electric-powered GA aircraft will become more available as technologies continue to improve, and, 2) the pursuit of newer engine designs continues, here is an interesting example: www.liquidpiston.com
In the meantime, I am learning the benefits of babying my car's engine with gentle accelerations, and also all of my vehicles currently powered by reciprocating engines. After all, it is a poor design that we continue to use because it works. My 1996 Isuzu Rodeo clocked 302k miles before a rod broke, my 1998 ML320 clocked 327k miles before the head gasket blew, and my 2008 Lexus hybrid is still running at 230k miles, although it is now past due for the next timing belt kit.
peripro@reddit
Don't push that timing belt too long. I thought I could get a couple thousand more before I changed the one on my DelSol, and teeth sheared off and the engine quit while exiting the freeway!
Thick_Dego_4683@reddit
As Sling Blade says “Ain’t got no gas in it. MmmHmmm.”
Bigboyzackman@reddit
Engines need 5 things to run, air fuel spark timing and compression. It’s unlikely that a timing gear would shear off in flight. We have two magnetos, so improbable that it’s a spark issue. The probability of all 4 (or 6 for y’all big money fells) cylinders loosing compression at the same time is improbable, and it’s kinda hard to run out of air. So it leaves us with one thing, fuel. Majority of engine failures are fuel related, either a bad fuel pump or simply running out of gas. Engines normally don’t die instantly, they die a slow painful death. I took my mustang to VIR for track day once, and had detonation that blew out 3 pistons, and I was still had over a mile before the pit, I made it, but a slower speed. I hate the way most CFIs train engine failures. They simply pull the power all the way out and teach their students to land in a field or some bullshit. The probability of that happening assuming the student checked the fuel is slim. What I teach is simply pulling the power back to 1900ish rpm, simulating a cylinder failure, and teaching my students how to divert and hold altitude. You’ll be surprised how often students who went to other instructors will come to me and I’ll do my bullshit and they turn a cylinder failure into a complete engine failure. Like damn you dumbass you could’ve landed at that airport 7 miles away that had a maintenance shop yet here we are in a field, dont turn a bad day into a terrible day. And yes I also teach complete engine failures because that’s what will be on the checkrides, but I hardly emphasize things in the ACS cause it’s all bullshit. I care a lot more about making good bc pilots than good operators. Sorry for my rant.
nixt26@reddit
This made me think, how would I know the minimum power needed for my airplane to maintain altitude? And in which configuration? Would deploying flaps be better or keeping them in with nose high is better? Seems like an important thing to now...
nixt26@reddit
Thinking more about this, best glide w/o flaps is probably the most efficient configuration. So just best glide it and if it climbs it climbs - until I'm near the airport...hmmn?
PiperFM@reddit
I don’t disagree, but be aware, 4 bangers OFTEN totally die when you loose a jug. If an old O-320 eats a cam lobe, you might as well not have an engine.
I know probably 4 people who totally lost an O-320 or O-200 after either having a jug just fall off, eating a valve, or shitting a cam.
O-300s and big bores run A LOT better on 5 cylinders… but I know a guy who landed a 207 short of the runway when he lost just one cylinder, can’t remember exactly what went wrong but he had basically zero power, could not make the runway.
CousinDazz@reddit
This needs to be taught and tested. There are so many more bad decisions that can be made with a partial failure. When it happened to me I honestly thought about pulling the throttle to idle which would have killed the engine just because I’d trained to glide into a field. At the time I remember thinking a full failure would probably be less stressful. I never trained to limp it to the nearest airfield but that’s what I ended up doing.
AlexJamesFitz@reddit
Would bet a substantial share of GA emergency landings boil down to fuel mismanagement.
CamelloVolador@reddit
Absolutely true. A student at our flight school arrived from his 300 NM cross country with three usuable gallons to spare in the 172. His reasoning: he wanted to arrive on time because he had a hockey game later that day. It scared the bejeezus out of all of us.
Obviously he was properly reprimanded and the school issued a new memo and renew its rules for cross country students.
aeternus-eternis@reddit
It's also somewhat insane that there's no blaring warning and your engine just stops. It's like 10 cents worth of electronics that is near-impossible to install due to regulations.
We all just accept that the vast majority of GA planes don't need low fuel warnings, skid warnings, water in fuel sensors, ADS-B collision warnings. Each of those are low cost and could save many lives, instead we've made it effectively illegal to install on most GA planes.
BLACKzj52@reddit
I'm still learning the basics and am aware that 3 gallons is too little. What i don't know is how many gallons should've had.. 10 gallons? If I'm not mistaken, the reg is to have at least 30 minutes extra (which 3gallons definitely isnt) but does that reserve amount increase the further you go?
CamelloVolador@reddit
No. For a daytime Visual Flight Rules (VFR) flight, you need enough fuel to fly to your intended destination and then for at least 30 minutes at normal cruising speed. In other words, you must have enough fuel to fly to the first point of intended landing. After reaching the destination, you need an additional 30 minutes of fuel at normal cruising speed.
For nightime VFR, the reserve is 45 minutes at normal cruising speed.
BLACKzj52@reddit
Understood, thank you. So he shouldve had more like 5 gallons? From what I'm aware, 172s burn about 10gph?
SemiProFakeCarDriver@reddit
Not defending the student at all, but the 172's burn is \~6gph, right (disclaimer: I have never flown a Cessna, that is what I heard and a quick Google search confirmed the number for _some_)? That is 30 minutes of reserve, while terrible judgement does that actually satisfy 91.151 in this circumstance?
jtyson1991@reddit
It's more like 7gph, at least in the 172S, and that's only if you're at 50% power and leaned out.
SemiProFakeCarDriver@reddit
😬😬😬
jtyson1991@reddit
So he really may have had more like 15-20 minutes left, and maybe not enough to go around after a balked landing.
unsuspicious_raven@reddit
Recipe for some surprise power off 180 practice
Creative-Dust5701@reddit
I trust he was dropped as a student, and a chat was had with local FSDO - student had no business being a pilot. Safety of Aircraft and Pax is the ONLY thing you should be thinking of.
I have a PA24 which came with a really nice Garmin BT intercom, it’s been replaced with a king push button intercom. Why? No distractions when up there you should be listening only to aviation traffic not your favorite podcast etc.
CamelloVolador@reddit
He wasn't. He's a good student overall who made a huge mistake that fortunately didn't end in disaster otherwise, it would surely be a hot-topic for any aviation Youtuber.
He was prohibited from flying at our flight school for a ten days and we made sure that any of the surrounding outfits didn't cater to him. Fortunately, he took it well and accepted his responsability. His flight instructor, on the other hand, had to take the brunt of the issue as he was supposed to supervise the flight and make sure the student made all of his stops, refuels and anything that needed his attention.
Creative-Dust5701@reddit
If It was my flight school I would have washed him out because of bad ADM.
1 - The hockey game was scheduled if it was must attend whyinthehell did student schedule an XC
2 - not refueling because behind schedule
How many more examples of bad ADM are there in this students history.
I had a cast iron bastard of a flight instructor who if i made a safety mistake i kept hearing about it for weeks. His point was I never want you to forget a mistake that could injure or kill someone. i still take the occasional lesson from him because he’s forgotten more than most pilots ever know
CamelloVolador@reddit
If he was a bad student overall with prior violations, I would agree to have him cut from out program but he's a good kid and a fine student, always the cheerful lad but more importantly, he pays his bills on time with a healthy credit line, and still has ME/IFR to go!
Vast-Negotiation9068@reddit
Get there-itis in action…
waveslikemoses@reddit
Before he bought his current one, a pilot at my local class delta had a bonanza that he crashed for exactly this. Dumbass didnt move the notch all the way while changing tanks, so the engine was trying to draw fuel from nothing which is why the engine quit.
nixt26@reddit
I'm a newbie but this just seems like a overall bad fuel system design?
waveslikemoses@reddit
No not necessarily! Just gotta do your due diligence. Some planes like the Cessna Skyhawk can draw from both tanks simultaneously without action from the pilot. Others require the pilot to switch every twelve minutes or so to prevent an imbalance.
John_B_Clarke@reddit
That's pretty much how John Denver, a 2700 hour pilot, died.
falcopilot@reddit
The fuel tank selector on that plane was in a weird place over the pilots shoulder.
Granite_burner@reddit
Not true. Denver’s plane had a mod in the fuel system, made it awkward to reach the tank switch. So it was his unfamiliarity with bad ergonomics in an experimental that bit him.
John_B_Clarke@reddit
Nonetheless, he failed to move the selector to the correct position. Why he failed to do so is beside the point.
ghjm@reddit
It's not that he failed to move the selector. It's that in that airplane, moving the selector required loosening the shoulder belt, taking your hand off the stick, twisting around in your seat and then struggling with a stiff knob. The NTSB found that while doing this, there was a tendency to inadvertently step on the right rudder pedal. The final movements of Denver's airplane were consistent with excessive right rudder. This all happened at 400 AGL so there was no time to recover.
So it's kind of the opposite: instead of going down because he failed to move the fuel selector, he went down because he did try to move the fuel selector, in an airplane built by a crazy person.
TransientVoltage409@reddit
Did anyone ever find out why the builder decided to relocate the valve like that? There must have been some rationale, no matter how faulty. As a builder I am endlessly curious about how other builders think.
ghjm@reddit
What I've heard is that the builder wanted to avoid running fuel lines through the cabin. Not sure if that's the whole story.
sadwcoasttransplant@reddit
Yes. I have a longEZ. There are fuel lines that run to a selector between your legs under the seat.
John_B_Clarke@reddit
Thank you for filling in those details. If I ever get around to building the LongEze for which I have plans and a build license I will be sure to not relocate any controls unless it makes absolute sense to do so.
FailureAirlines@reddit
Must.. not.. make... right.. rudder... joke.
Granite_burner@reddit
Don’t know about “most”, but here’s photographic proof my personal sample size of one had nothing to do with fuel mismanagement…
#3 jug
NuttPunch@reddit
He also had his certificate revoked for a drinking problem but chose to keep flying illegally because he felt he could.
Ok-Tale-5112@reddit
That and he tried to cut his ex wife in half with a chain saw.
NuttPunch@reddit
Annie’s song
TyrannoNerdusRex@reddit
He what now?
Ok-Tale-5112@reddit
John Denver was Hooch level crazy..
Ok-Tale-5112@reddit
When he found out his wife wanted a divorce, he said she'd get half of everything and started cutting up the bedroom with a chainsaw and she almost got cut with the bed
Chriscom67@reddit
He cut their dining table, bed and headboard with a chainsaw. It's widely reported, including by him, that he "almost choked" his wife, but on the bright side his soon-to-be ex-wife was a chainsaw-free zone.
lawrencebillson@reddit
He knew E from F on a guitar...
CryptographerRare793@reddit
I've been told this is a common thing with bonanzas. Not necesarily riding the failure all the way to the ground but causing a fuel starvation issue by not turning the selector all the way to the detent.
Captain_Nipples@reddit
Seems like something that should be easily fixable with better design/engineering instead of relying on humans to do the correct thing
DeltaVZerda@reddit
Yes but most GA planes are older than the pilot's parents.
waveslikemoses@reddit
Is it really? I did not know this
bwh520@reddit
And he rode it all the way to the ground without trying to fix that? That's a memory item in any plane requiring tank switch's.
Aerodynamic_Soda_Can@reddit
Hell, it's even a memory item in a 172 which doesn't require switching tanks!
It's amazing how unproficient some pilots can get over time without realizing it. Or perhaps a training failure they never realized?
Blumi511@reddit
Last weekend I took my dad for a flight. Usually, watch and my tablet should notify me every half hour to switch tanks - not matter if I fly Piper or Cessna.
Still, I always get anxious in the minutes before the timer runs down. This time, my watch did not notify me.
I switched after 31 minutes and felt like an old man cause I did not have my alarms in order.
LowerYourStandards_0@reddit
If you have an analog clock in your panel, here's a technique that works for me: if the minute hand is on the left half of the clock, I'll run on the left tank. Right half, right tank. As a bonus, if you forgot to switch you know exactly how long you forgot for.
Granted, for this to work you have to remember to scan the clock... Lol. Even so it can be a backup to your watch. Or, better yet, the watch can be a backup to the clock technique!
Separately, I'm not an expert on light plane fuel systems, but I don't like running a Cessna other than "both" unless correcting an imbalance... Even if the plane prefers one tank over the other in "both," it'll still be configured to feed from the other one in the event you have a bad day and forget to switch. It's a free layer of defense against an easy error
_Banana_Republican_@reddit
Some older Cessna models can apparently be susceptible to vapour lock at higher altitudes if not run on a single tank
paid_shill_3141@reddit
I know of one case where someone in a 172 managed to switch the fuel from left to off instead of both. The resulting silence apparently turned his brain to mush and he glided all the way to the crash site. At least he walked away from it.
ValuableJumpy8208@reddit
Switch’s?
waveslikemoses@reddit
Yup. Perfectly good airplane was ruined
californiasamurai@reddit
Of course it's a bonanza. Of course it's a guy that bought a bonanza. Why am I not surprised?
TheDrunkSemaphore@reddit
I only did 25 hours 20 years ago, but I distinctly remember being taught about the fuel tank switches and thinking to myself "I'm gonna forget this one day and die"
JabbyJabara@reddit
This, after an accident report is completed and is found to have pilot error fuel mismanagement, everyone and the media shuts up real quick.
Because its no longer about the plane and dangers of flight, its now looking at the human and the hubris thinking they did nothing wrong.
AWACS_Bandog@reddit
A well-ish known CFI in my area almost crashed a brand new student's Musketeer in the practice area, all because he didn't bother switching the tanks after running one of them dry.
Had plenty of gas in the other wing
goonsquad4357@reddit
In terms of fuel exhaustion or not switching fuel tanks?
FlyingS892@reddit
First one, then the other
jawshoeaw@reddit
No need to bet, that’s established fact
Straight-Mountain119@reddit
Don't know about mechanical failures, per se as a cause. I've known them to happen to other of my pilot friends. A failed piston, valve, or mag. I know my instructor, an "old freight dog" as he sometimes referred to himself, was old school, like my Father. They both flew DC-3's and such. My instructor drummed into my head fuel awareness. Said "The only time you have too much fuel is when you're on fire"......and situation awareness as well. Always stick the tanks, never trust the fuel guages, as they're not linear. Always calculate how much flying time you have with the fuel you have, and know your fuel burn. And keep the fuel "thingy" on both tanks. Keep track of all that and weight and balance. I believe one has to, at least with a Bonanza, keep recalculating CG because of the position of the fuel tanks. And be aware of fuel shifts between wings, if doing maneuvers. Aware of anything that affects amount of fuel. How much does it burn on take off and climb out. ? I took my Father up on a trip XC, not a long one, but enough where I had to be aware of any fuel stops needed there and back. It's something you have to have in mind always. Always be planning for things that might go wrong or such. My instructor and I had to do a field cylinder change in one of his planes, on one trip. We planned and took his mechanic to help and sign off, as it was a field out of town. We had left the plane at another field, as it would not have made it back. It was a crack in the cylinder and engine very rough. We flew back in his other aircraft and did the change, flew back with me alone in one, and him and his mechanic in the other. Except for the work, it was uneventful, and an education. My instructor was also an A&P, like my Father. Me, on the other hand have only worked on ground vehicles, as a mechanic. The FARS require any pilot to become familiar with any/all information regarding the flight, before one takes off. Theoretically, there is no way one can know all the information, as everything changes, and the information is not static. And there is so much available, that one could spend hours planning and obtaining that information. There always seems to be something, in hindsight, that one learns to do better the next flight as well.
Jay_Ge90@reddit
Few that I can think of: Incorrect mixture setting/mixture too lean, high rpm low airspeed (steep prolonged low speed climb in hot weather), incorrect cowl flap settings, high MP pressure low rpm, incorrect use of carb heat in climb, rough handling of throttle.
Kemerd@reddit
Crappy maintenance
Weird-Somewhere-8198@reddit
Cylinders heads cracking, that happened to me once. Also in higher performance aircraft you can over torque the engines, but that’s user error. I’m sure there are statistics that show that fuel starvation is the leading cause of engine failure. You’d be amazed how many people just jump in an airplane and go flying without doing any kind of preflight inspection.
underdog5891@reddit
Fuel starvation is the number one cause.
Fostang@reddit
I’ve had two engine failures. One of them was a fuel servo the second was the number one intake valve got sucked in and ate the camshaft sending metal thru out the entire engine. One of them totaled the plane the other cost 250k for a new engine etc etc.
Manifestgtr@reddit
I am a diligent motherfucker…I follow checklists to an almost melvin-like degree. One morning it was really cold and we were putting winter plates on the airplanes. Dispatch came out with my plates right as I was going to check the fuel quantity manually (in an RV-12 you do that by looking at the tank in the baggage area). Just those few minutes of chatting and having something “different” happen skipped my brain right over that step. Not only that but the airplanes are basically always put away with full tanks…everyone knows why, blah blah blah. So that extra bit of “expectation bias” creeped in. Do all my checks, taxi out and run up…if there wasn’t an extra “manually check fuel tank” on the runup list, I would’ve absolutely departed with a quarter tank.
Up until that day, I had absolutely no idea how these things happen. I had two holes line up in the Swiss cheese and if I hadn’t followed the runup checklist to a T, a third hole would’ve shown up and I have no idea what might’ve happened out in the practice area. Maybe the annunciator would’ve saved my white ass…who knows. The point is, if you would’ve asked me about my chances of having a fuel starvation incident 24 hours earlier, I would’ve laughed derisively like an old timey villain. With that one, sobering demonstration, I learned precisely how these things happen and that nobody is immune. Don’t ever think you’re immune. Fuel quantity is now at the very top of my mind during preflight…
nimbusgb@reddit
Time spent running on the ground ..... minimal. Time spent running in the air ..... 98%?
When they fail .... they'll be flying.
Why do they fail? 1940's technology.
usmcmech@reddit
After removing fuel exhaustion/starvation, the most common mode of failure in a piston engine is a burnt exhaust valve on one cylinder.
This creates a partial engine failure with a violent vibration in 4 cylinder engines, 6 cylinder engines have serious but manageable vibration when running on 5 jugs.
davidswelt@reddit
And would that be preventable with regular boroscope inspections, or compression checks?
HorrifiedPilot@reddit
Preventable by never running the engine lean of peak
ThatHellacopterGuy@reddit
There’s a big difference between attempting LOP on a carb’d Lyco or Conti with (maybe) a single EGT probe, and running LOP on an injected engine with decently-matched injectors and an engine monitor with all jugs EGT probed.
imjustmatthew@reddit
That's interesting and something I've never heard. Can you explain more about how the valve failures are related to running lean of peak?
AndyLorentz@reddit
It would be more accurate to say it's preventable by never overheating the cylinder heads. The process of reaching peak EGT can potentially do that.
When the heads overheat, there is the possibility of warping the valve seat. When that happens, the valve doesn't have an even transfer of heat to the head, and also tends to lose the ability to rotate, so one part of the valve develops a hot spot and eventually melts.
RyzOnReddit@reddit
Is anyone not doing a big pull to go LOP in 2025? I normally run ROP but this can be really helpful to get temps down in the summer…
HorrifiedPilot@reddit
Rich of peak is the move and if temps are getting toasty, just enrich the mixture a lil bit
RyzOnReddit@reddit
Not necessarily - the turbo continentals on the Seneca can pass 390 at full rich in cruise climb if it’s warm out, going LOP can drop the temps and fuel flows at the same time.
HorrifiedPilot@reddit
I mean LOP on your standard GA engines. Once you start getting into higher horsepower mechanical aspirated stuff, much more variation on what works and what doesn’t.
AndyLorentz@reddit
So, I'm a car guy (auto mechanic for 23 years). Manual control of fuel mixture is so 1920s. Computers do things much faster than humans can, and in the 23 years I've been working on cars, I can count on two hands how many ECUs I've replaced. Most of the time that has been because of external damage (the mid-2000s Acuras would have the evaporator case drip water into the ECU harness, causing a short)
I'm a fan of the newer Diamonds with their VOTER systems.
HorrifiedPilot@reddit
Burns out valves
FlyGuyBurner@reddit
Oh yeah? Tell us more.
HorrifiedPilot@reddit
Burns out valves cause it overheats the exhaust, source: I work on engines
FlyGuyBurner@reddit
I’d bet a lot of aircraft referred to here are school planes which already get compression checks every 100 flight hours. The differential compression check is useful, but not as authoritative as many assume it to be. I don’t know about borescoping cylinders that aren’t displaying problems. Installing an engine monitor, regularly dumping the data and analyzing it would help.
odins_gungnir@reddit
I started downloading engine data recently and playing with it. Are there any suggestions on what to look for specifically?
FlyGuyBurner@reddit
Make an account at savvyaviation.com and upload your data. It gets a lot easier to look at. Consider buying one of their analysis subscriptions, you’ll learn what their experts look for and what their AI looks for.
Not_me92@reddit
Happened to me on a 4 cylinder. Below 2000 rpm I thought the engine was going to separate. I was able to maintain max of 2100-2200 at full throttle.
otirkus@reddit
Makes sense, these engines will rarely "quit" all of a sudden when something catastrophic like a valve failure or leak occurs. They'll lose power and run rough, and if you've planned your flight properly you should be able to land at a nearby airfield.
redvariation@reddit
This happened to me in an air-cooled VW Bug. Luckily on the ground.
Grand-Jacket-8782@reddit
“Luckily on the ground” implies that it wasn’t always on the ground… 👀
GayRacoon69@reddit
Fuck there goes my plan of trying to fly a VW bug
redvariation@reddit
The engines can fly in experimental aircraft though!
Jonne1184@reddit
There are multiple certified engines based on VW engines.
flycrg@reddit
How often is that VW Bug in the air for it to be lucky it happened on the ground?
/s
redvariation@reddit
I did some fast runs over some speed bumps, but not sure if I got airborne, or just unloaded the suspension!
shockadin1337@reddit
how do you even get a 4 banger engine hot enough to burn the exhaust valves? run the engine at 100% power leaned out every day? i have limited experience with continentals but the o-320s we run see a max of around 1500 on the EGTs
FlyGuyBurner@reddit
Depends on the cowling and baffle design. My school’s 172s are all 4 cylinder and we will see CHTs in the mid 400s sometimes during takeoff despite the mixture being full rich.
shockadin1337@reddit
Theres a massive discrepancy between our two cherokee 140s, one it is nearly impossible to see CHTs over 370 and the other one will get up to 415 on the ground waiting to take off. Exact same engine, amazing what engine cowl design/baffling will do
FlyGuyBurner@reddit
You can definitely maintain altitude with one jug failed, even climb, depending upon the conditions, including 4 cylinder engines. I’ve lost a jug in flight, and one student at my school lost one due to a head that cracked in flight. In both instances, the Lycoming 360 made enough power for marginal climb, and the airplane made it back to the runway.
htnut-pk@reddit
My only failure came after over 1500 hours of piston time: Head of an exhaust valve broke off. Same result as you described.
Was an O320 overhauled in the early 1980’s right before the design of the valves were changed to better survive 100LL.
milnerq@reddit
I had a cylinder blow at the beginning of the month because a mag fell out of time and made it start detonating. Runup and everything checked out before takeoff. Crazy vibrations and couldn’t hold altitude. Happened after takeoff 500 ft AGL. Luckily we got back on the runway safely. When we got the cylinder off there was a big hole right by the valve.
Kallaan12@reddit
Had a cylinder give on landing last week. Yupp
Due-Weekend9813@reddit
This happened to me and I have a 6 cylinder. happened exactly as you said.
Able-Negotiation-234@reddit
Really, I have seen 1 that was not related to either the pilot or mechanic, or both since 1990 as both an A&P and line captain for 25 years, for the most part do the maintenance on time and by the book , they work good last long time.
_toodamnparanoid_@reddit
Hi,
I bought a Piper Navajo a few years back and the bank required the engines be overhauled as a part of the purchase.
I suffered three separate engine failures; you tell me if I could have caught them during preflight:
Engine failure #1 -- multiple right engine fuel injectors vibrated loose and the engine quit right at Vmc while spraying fuel everywhere. Fault was with the engine overhaul shop and fsdo determined it would not be noticed on a reasonable preflight.
Engine failure #2 -- two of the new cylinders fractured on the right engine, parts bounced around the engine and also took out the turbo, that was fun because it was also an ILS to mins -- there was no missed approach option on that one. It was found to be a metallurgical issue from the factory.
Engine failure #3 -- the oil return line on the left turbo disconnected in flight and oil pressure dropped very rapidly. I precautionary shut down before the engine stopped, but odds are it would have quit and seized less than half a minutes later (once in the ground the local A&P said there was no oil in the pan at all). FSDO found the problem to be with the A&P who attached the turbo to the engine once it was returned from the overhaul shop and was not something which could have been caught on a reasonable preflight.
otirkus@reddit
Wait ... you had three heartstopping experiences in your plane? That's wild. I'd have been scared to fly after the second one.
Aerodynamic_Soda_Can@reddit
Quick question for the shop that you're having do all these failed overhauls: what the actual fuck dude!?!?
Also, please tell me you're using a new shop by now? Lol
_toodamnparanoid_@reddit
It was a single overhaul period (piper navajo has two engines and the bank required both be overhauled with the purchase).
freebard@reddit
Those stories are enough to make a guy a believer in the "don't euthanize an engine at TBO / most failures are infant mortality" theory pushed by a well known A&P.
PiperFM@reddit
…and then you have rusty dogshit flat Lycoming lifters take out the cam and you loose power on takeoff.
I know lots of people that has happened to, almost including myself
Aerodynamic_Soda_Can@reddit
Well dang, I'm not sure if that's better or worse!
ghjm@reddit
I think the story is that all three failures came from the same overhauls.
MNIMWIUTBAS@reddit
You're not re-torquing your fuel injectors during preflight? I feel like that first one is on you.
A7XmanbeaRPiG@reddit
Which is exactly why you shouldn’t be replacing engines just because they reached TBO if they still run fine. Don’t expect banks and insurance to understand that though
gwav8or@reddit
Please tell me you switched insurance companies also. They shouldn’t be able to mandate an overhaul. I’d be they mandated it based solely on TBO. Did they insure the engines they forced you to overhaul?
_toodamnparanoid_@reddit
The bank mandated the overhauls. They can require anything they want as a part of the loan...
otirkus@reddit
Most commonly it's due to fuel mismanagement or carb ice. Nothing wrong with the engine, just pilot error. It's very unlikely you have a catastrophic failure where the engine just quits. Usually it'll start running rough and slowly lose power. Precombustion, detonation, etc. will result in extra wear and tear but it's nothing the inspections won't notice. Perhaps if you use the plane a lot and abuse the engine, there's a higher chance it will fail, but even then it's not like it will turn off all of a sudden - it'll start running rough and losing power before quitting.
MDT230@reddit
So many reasons. Vapor locks in fuel tanks, Fouled or cracked plugs, Overuse or underuse of mixture and fuel starvation being the biggest one id say.
GenericName1442@reddit
My 2¢, a lot of GA is not kept up to date as well as it should be. Pilot errors or just not keeping up with the plane properly in an attempt to save money. Think of how old a lot of the GA fleet is because modern airplanes are unaffordable for most people.
Winesickle2525@reddit
I had an engine failure from a failed intake valve and there wasn’t any realistic way to have predicted it, from what the mechanics ended up saying.
Valve train failures seem to be pretty common, and I think they are related to the fact that these engines are air-cooled and you end up with a lot of heat related metal fatigue that would be less likely if the engines had better heat management- with water cooling for instance.
Reliability could be greatly improved with more modern tech like water cooling and FADEC, among other things. But we are kinda stuck with these old dinosaur engines and their associated problems.
MostNinja2951@reddit
Water cooling is not an improvement.
Winesickle2525@reddit
Why do you say that?
One of the biggest problems with Lycomings and Continentals is heat management and the huge temperature swings that any air cooled engine will undergo. Which exaggerates all metal fatigue. At least with water cooling you actually have a thermostat and a stable engine temperature.
MostNinja2951@reddit
Because water cooling is heavy and the performance loss is not going to be acceptable for most GA applications.
Granite_burner@reddit
When my engine swallowed an exhaust valve it continued to run on three cylinders, with the fourth cylinder beating the exhaust valve remnants into the piston, for over five minutes.
Would that modern water cooled FADEC engine do as well once it failed? I doubt it.
Festivefire@reddit
I'd rather have an engine that doesn't fail than an engine that fails often but can sort of deal with it.
Granite_burner@reddit
Also, once “an engine that doesn’t fail” is the mindset the habits of being prepared for in-flight engine failure get lost. There are many nuances….
Granite_burner@reddit
Thing is, I’m unconvinced there is such a thing as “an engine that doesn’t fail”, or ever will be. Preventing one failure mode just reveals another, less frequent failure, hopefully much much less frequent. Read Henry Petroski‘s To Engineer is Human, and also Carroll Smith‘s statement about all failure being human, in Engineer to Win for good perspectives on eliminating failures.
I’d prefer as ideal the least failure prone, most resilient design possible. Both are important, ignoring one while striving to improve the other is not good. But a lot of times it seems efforts to reduce failure make them much less frequent but much more brittle. Those tradeoffs need to be consciously considered and intentionally accepted, which is very hard as they become more infrequent, unpredictable, and novel. It’s why discussions like this are useful and necessary.
My personal experience with the engine continuing to run with a broken exhaust valve isn’t universal. I could’ve had a total engine stoppage in flight. But I didn’t, and it’s a good conversation starter.
graphical_molerat@reddit
It would if you write the FADEC software to at least try. Like they do for military vehicle engines. Put a bullet through the engine block of a Humvee, and if you didn’t hit absolutely vital bits, it will try to continue running. Unlike civilian car engines, which are made to stop in case of trouble.
Mediocre_Paramedic22@reddit
Fuel mismanagement and engine corrosion.
kytulu@reddit
Here's a general walkthrough of a 100hr 172S engine inspection at my flight school:
Perform pre-run, check full static RPM, idle RPM, mag drops, mixture rise (on engines with that AD).
Drain oil while hot. Remove the oil screen and check for metal particles. Remove the oil filter, cut open, and inspect for metal particles.
Remove, test, gap, and clean the spark plugs.
Perform a compression check on each cylinder.
Perform a visual inspection of the engine, looking for oil leaks, chafing lines and wires, intake and exhaust leaks, binding controls, exhaust/muffler cracks, anything that looks wrong or out of the ordinary. There's a list that we follow.
Correct any discrepancies. Refill the engine with oil. Perform post-run and check the same as the pre-run.
We don't split the engine case open and inspect the bearings or other internal components.
If we find metal in the filter, we borescope the cylinders if it's aluminum on the premise that a piston pin has shifted or something else in the cylinders is going sideways. If the compression check is less than 60psi, we listen for escaping air from the intake (stuck intake valve), exhaust (stuck exhaust valve), or oil fill tube (bad piston rings). If we find ferrous metal or metal other than aluminum, then a more thorough inspection is required to determine the source.
Different flight schools place different emphasis on maintenance. FWIW, most CFIs apply at our school because we put a lot of effort into ensuring that our aircraft are airworthy. We have more than a few high-time engines, and I have performed a few cylinder replacements, reamed valve guides, fixed leaks, etc.
Another issue is that a lot of GA owners will defer maintenance because of the cost. For example, a complete cylinder runs about $1500 and takes about 8 to 12 hours of labor to replace. A short-pockets owner might just change the oil and check it again after 25 hours when they find metal.
HungryCommittee3547@reddit
It's amazing to me that found metal doesn't result in an immediate grounding until the source is identified and repaired. The engine is eating itself and will fail. It's a ticking time bomb at that point. It might run 3 more hours or 300, but I'd just as soon not be in the air when it decides to take a dump.
kytulu@reddit
For a flight school, it does. Private owners are not as restricted.
We found metal in the oil and traced it back to the #3 cylinder piston pin. Replaced the cylinder, sent it on a break-in flight, and changed the oil 25 hours later. Found the same amount of metal. Traced it to the #4 cylinder piston pin. Replaced the cylinder, sent it on a break-in flight, and changed the oil at 25 hours. We still found metal, but less than the amount required to tear down the engine. As none was in the oil screen and all of it was in the filter, it was decided that it was residual from the bad cylinders, and the filter was doing its job. At the next 100hr inspection section, I found a few small flakes in the pleats of the oil filter. At the 100hr after that, I found no metal at all.
PiperFM@reddit
On one engine I used to work on we had 1/4 cup of aluminum in the screen.
“Send it, residual!”
And he was right lol engine was fine. We checked for I believe lead as that’s what the main bearing was alloy’d with, but you probably won’t be wrenching on that series of engine anytime soon haha
primalbluewolf@reddit
Thats all engines really - just the clock runs a bit faster on some of them.
Most light aircraft engines will have an SB or similar to the effect of "a small consistent quantity of non-ferrous metal in the oil filter is not cause for concern".
r00kie@reddit
Lycoming has an SB that outlines exactly how much metal is allowable and what the corrective action should be.
https://www.lycoming.com/sites/default/files/attachments/SB480F%2520Oil%2520ServicingMetallic%2520Solids%2520Identification%2520After%2520Oil%2520Servicing%2520and%2520Associated%2520Corrective%2520Action.pdf
fhfm@reddit
Couldn’t agree more. Even in my car, if I found metal in the oil beyond a few specks, it’s straight to the shop, and that’s knowing I can just pull over if there’s a problem.
ltcterry@reddit
My engine failure was the result of a mechanic using the wrong drain plug on an Arrow and the oil drained out. Took about 20 minutes. Airplane was totaled but I was fine.
I don’t think most engines fail. You just hear about every one. I’ve read there’s one failure per 4,000 hours of flying.
I suspect in the real world most engine failures are actually Carbon Control Unit failures.
FeatherMeLightly@reddit
Cessna or Cherokee (Piper), so that's Lycoming and Continental and maybe some experimentals, essentially all GA engines.
Season? No. Maybe in AK, but the NE CONUS experiences some bad winters and I personally don't see a rise in accidents there due to the season.
Accidents happen for 2 reasons. Mechanical failure, or piss poor pilot decision making, some could be a combination of both.
As others have said, fuel is the number enemy. The company I have been with has 50 hour mx intervals, if the pilot says it's not flying until something is fixed, it gets fixed no BS.
The only losses to date, other than acts of God are due to pilots NOT following emergency check lists. Planes landed off port with on tank completely empty and the other slam full.
Go figure.
Sinorm@reddit
The next most common cause after fuel issues are the magnetos (a mag failure was the cause of my emergency landing). If you encounter any engine roughness, after you pull the carb heat make sure to cycle the mags and try running on just one mag or another. A misfiring magneto will cause major engine roughness.
nguyenm@reddit
One of the under-recognized perks of of multi-engine training is when doing a magneto checks on each engine, the PIC have a clear opportunity to do an immediate comparison between what's expected and what is out of the norm.
During my CMEL, thanks to the institution's logical policy of not charging hobbs hours if you taxi to run-up and return due to not feeling confident with the aircraft, i've cancelled maybe 3-4 flight lessons due to one of the two engines not performing within margins during mag checks (rpm drops too much).
jawshoeaw@reddit
Failing a mag check I thought was an automatic fail, return to base for any aircraft
satans_little_axeman@reddit
It is
jawshoeaw@reddit
That’s why the comment confused me. How was what he was describing a “perk”
Bunslow@reddit
the perk, he said, was that the institution didn't charge for the engine time if the engine failed a mag check.
i gather that, while all places expect you to reject and squawk a mag failure, that they will still charge you the 0.3 hours of engine time for startup and runup.
TravisJungroth@reddit
"Your airplane isn't safe to fly."
"Oh crazy. That'll be $60."
ghjm@reddit
Suppose you own an airplane with a partner, Bob. You go to fly it and fail a mag check. You burned some fuel and used up some time on the engine reserve. Should Bob pay out of pocket for this? Why?
TravisJungroth@reddit
I think people saying yes aren’t realizing that you’re flying and Bob is not.
I’d say no, you should pay unless you have a deal where aborted flights just get put down as Mx time, which no one pays directly for and is split between the partners.
But I’m not a co-owner of a flight school’s airplane. I’m just paying for a rental.
I owned a flight school and that’s how I did it. I understand the flight school’s side. If they’re using leasebacks, they’re stuck in the middle. They’re still paying 80% or whatever of the cost to the owner. But this is why you have it in the leaseback agreement the owner doesn’t get paid for aborted flights. The taxi really didn’t cost the owner much. Low fuel use, engine wear, etc.
ghjm@reddit
Sure, and it makes a difference whether we're talking about a commercial flight school, flying club, small partnership, etc. My point was just that yes, it sometimes does make sense for you to have to pay $60 because you didn't fly.
I guess the most obvious case is if it's just your own airplane with no partners. Then obviously you pay, never that's nobody else who can.
TravisJungroth@reddit
What a silly point.
KITTYONFYRE@reddit
yes because bob owns the plane lol. but that’s not analogous to the above situation where you’re renting
Ok-Selection4206@reddit
Yes..
__joel_t@reddit
I interpreted the perk as being able to compare left and right engines' behavior during the mag check.
nguyenm@reddit
Thanks for identifying it! The school's perk is nice too, looking back.
R-slash-IHaveNoName@reddit
Usually when you fail a mag check you can run the engine hot to burn off any extra fouling or troubleshoot. If it doesn’t resolve then I would return
nguyenm@reddit
I had a mag check failure after the lean burn trick, and looking back I can't believe it the occasion, on my CMEL checkride. The DPE was extremely nice, and helped me throughout the way as both he and I tried to get the engine to perform as it was my second reschedule (without prejudice) already.
But yeah, somehow it took me three reschedules to finally do my CMEL checkride and it also fell on my birthday. I passed, thankfully.
Drunkenaviator@reddit
You gotta get those numbers up, those are rookie numbers! My CSEL checkride was rescheduled 22 times. Including one for the DPE literally dying.
rbuckfly@reddit
Roughness yes, but not failure.
Weaponized_Puddle@reddit
Will the roughness not eventually devolve into a catastrophic failure?
rbuckfly@reddit
No, reduced power yes, increased roughness yes but will not cause the engine to quit.
FlyGuyBurner@reddit
What if the bad mag is advanced and causing preignition?
rbuckfly@reddit
Then you land
FlyGuyBurner@reddit
Point is this: mag issue CAN become catastrophic failure.
rbuckfly@reddit
You’re reaching. If the aircraft continues to operate for an extended period on one magneto, it can lead eventually to other issues. The OP speaks of a sudden catastrophic engine failure. Single mag failure “ain’t it”. Dual mag failure, (how many of us have ever heard of a dual mag failure?) then yes she will quit.
FlyGuyBurner@reddit
Slipped magneto timing which has advanced can -melt- a piston.
rbuckfly@reddit
Agree….eventually cause an event. But if you drop a mag…you will have some time on your hands. Unless you’re on a long range over the ocean ferry flight.
Sinorm@reddit
Depends on how out of sync the bad mag gets, it can cause major issues. Either way it is easy to resolve by switching. I’ve also heard of bad magneto switches vibrating into a position that killed both mags, a quick toggle of the switch brought the engine back.
External-Reaction804@reddit
Fuel starvation. Period.
PhillyPilot@reddit
Generally a well maintained engine that has an engine monitor with a pilot that can read said engine monitor will not have catastrophic failure in flight. These engines have millions of combined hours on them and they don’t just fail out of nowhere generally speaking.
twarr1@reddit
A few years ago I did a deep dive into the NTSB incident database and found an inordinate amount of incidents were cause by fuel mismanagement.
Even more surprising were the number of Part 121 emergency declarations due to low fuel.
JadedJared@reddit
Part 121 emergency fuel declarations are usually not due to fuel mismanagement.
twarr1@reddit
Those are 2 statements. Separated into 2 paragraphs.
How do you get ‘fuel management’ from:
“Even more surprising where the number of part 121 emergency declarations due to low fuel”
Do you feel like you need to be right even if you have to make shit up?
JadedJared@reddit
Because you said it was even more surprising than the amounts of GA incidents due to fuel mismanagement.
MJG1998@reddit
Fuel mismanagement would not be a fair characterization of most 121 fuel emergencies.
Unlucky_Geologist@reddit
We declare an emergency due to low fuel usually when unexpected weather builds up. Those aren’t critical emergencies but, we declare nonetheless so they don’t become critical. It’s much easier to explain “we were holding and weather rapidly deteriorated at our alternate so we skipped the line and landed at JFK before we put ourselves in a corner” rather than “we went to our alternate ran out of options and shot an approach below minimums and bent metal.”
Cool-Acanthaceae8968@reddit
Yeah.. piston engines suck.
But over 2500 hours behind them and I only had one failure… cause inconclusive but we replaced the fuel injection system and it went away.
Most of it is fuel exhaustion, fuel mismanagement, and carb icing.
pisymbol@reddit
"piston engines suck" - yeah, they are basically a vacuum pump, right?
Cool-Acanthaceae8968@reddit
Not when they are boosted
pisymbol@reddit
They sure do. They just suck less. Or more depending on how you look at it! (read: $$$)
DisasterStriking3053@reddit
Exhaust valves sticking Carb ice Fuel starvation Oil depletion
Emotional_Debt9322@reddit
Fuel mismanagement, my instructor landed a plane on the freeway because apparently on a cross country flight he forgot to switch the tanks, and ended up just draining the left one
megaduce104@reddit
they really dont fail that often. these engines are basically bulletproof. as long as they are maintained well and operated correctly, they are very reliable
ive got 2000 hours in GA piston aircraft, ive only had one engine failure
EpicGaemer@reddit
What caused the failure?
graphical_molerat@reddit
2000h and one failure. That does not sound reassuring, to be honest.
Ok_Battle121@reddit
Not paying attention to oil temp & pressure gauges. Seems to be more often with newer PPL and CPL students, IFR students tend to focus on a lot of instruments and readings.
motoxnate@reddit
Well you see most planes are in flight most of the time the engine is running
Flyguy22U@reddit
I dove deep into this, if it is a mechanical failure it’s fuel related, mostly restricted or contaminated fuel. Also The fuel servo/carb and injectors are a single point failure on piston aircraft engines. fuel restriction or fuel line failure, many fuel tanks have only 1 vent that can get blocked causing a fuel flow restriction, of course contaminated fuel blocking the screens, being the wrong fuel or water contamination is common in mechanical failures
Wallphotography@reddit
Self hatred
Field_Sweeper@reddit
If you even THINK about spending money on anything other than the plane... it breaks right before you do. Or in my luck, right after. lol
Field_Sweeper@reddit
Lack of/Improper maintenance.
Occams_ElectricRazor@reddit
OK so coming from a 7 hour trainee...What's the benefit for a plane to NOT have a "both" in the fuel selector? Why would you want to select one tank over the other and not keep it balanced?
MostNinja2951@reddit
Aside from fuel issues and pilot error there's the fact that metal fatigue can be very difficult to detect. A 100 hour inspection isn't tearing the entire engine apart to do dye or eddy current checks on every part and the usual check for metal in the oil won't reveal an internal crack. This means there can be cracks that are hidden until they propagate to a point where the part fails. Up until failure the engine is running perfectly and then a vital part shears in half and you're hoping you have a good landing site within glide range.
JJ-_-@reddit
do average non A&P pilots know about dye penetrant and eddy current testing ??
CreatedByGabe@reddit
Hey, average non-A&P pilot here. No.
davidswelt@reddit
You may come across it because of ADs.
IronLeviathan@reddit
Sure they do, but there’s a lot of difficulty here. There are parts that are dye pen tested, but the crack or indication has to be at the surface, so it still doesn’t help identify latent failures. not every part can be eddy current tested, as the shape of the inspected part is important. Ultrasonic testing can be done, but every part needs to be characterized in a known good condition, because the data is comparative.
For a lot of things, the metal is inspected ( Ultrasonic )prior to machining, and dye pen tested after. And this is the best you can do.
Let me know if you have questions. It would help to look at some YouTube content about these inspection methods, to get a better understanding.
jawshoeaw@reddit
Average? Hard to say. Anyone interested in mechanics should
mild-blue-yonder@reddit
It’s usually an issue of having too much air in the tanks.
Sparkily_Broccoli@reddit
The line guy messed up and put in sailboat fuel.
californiasamurai@reddit
One day, the 85 year old doctor got tired of the line guy's shit and did it himself.
Yuri909@reddit
After that emergency landing, it became a beachcraft.
californiasamurai@reddit
Why did I laugh at this?
cecilkorik@reddit
Wow, that's even worse than accidentally getting sailplane fuel!
girl_incognito@reddit
Take your damn upvote
sevettjr@reddit
I had an engine throw a piston rod once. The rod poked a hole in the crank case, and all the oil ran out. Fortunately, it was a twin, so the spare engine got me to a nearby airport.
Mobe-E-Duck@reddit
So far I’ve had two. One was a cracked cylinder causing some loss of power and all sorts of fluids going on vacation.
The other was an inop aux fuel tank gauge.
Airplanes get old and pistons are usually last in line for extra spending. They make less money so they get less attention. Simple as.
BeeDubba@reddit
If you're interested, take the time to dig into the AOPA McSpadden reports. They take the data from the NTSB and present it in a relatively easy to digest form.
https://www.aopa.org/training-and-safety/air-safety-institute/accident-analysis/richard-g-mcspadden-report
There are lots of studies out there. I believe most show the single most common mechanical factor is either fuel starvation or fuel contamination.
https://www.avweb.com/flight-safety/accidents-ntsb/why-engines-quit-failures-are-avoidable/
The reason you don't get answers is because the NTSB doesn't have the resources to resolve every power loss. In 2024 there were over a thousand general aviation accidents. The NTSB must focus its limited budget on matters that impact the public, and unfortunately GA just doesn't rank that high on the public's give a crap factor.
flybot66@reddit
Watch Paul Burterelli's YouTube: https://youtu.be/mwpzTnLC8BY?si=jSP6smYc7P0PDOjh
Plus_Definition7802@reddit
baffle seals failing, ask me how i know.
stop_yelling_please@reddit
Tell us about how a baffle seal led to an engine failure. Sounds interesting.
Plus_Definition7802@reddit
lost engine power upwind at 300ft agl. had idle power with power lever set to max. i’ll leave this advisory circular here for your viewing pleasure.
https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_20-105C_FAA.pdf
stop_yelling_please@reddit
What does this AC have to do with a baffle?
Plus_Definition7802@reddit
It mentions how baffling of the muffle can cause engine power reduction and failure. Like you asked.
Internal Failures of Mufflers. Engines can experience substantial power reductions and failure when the internal baffling of the muffler breaks loose and partially obstructs the muffler’s exhaust pipe. Indications of this condition may be a large reduction in rpm, rich mixture indication, rough running, vibration, and after-firing. At each annual or 100-hour inspection, the muffler should be inspected internally for cracks and condition.
primalbluewolf@reddit
Thats the muffler internal baffling, not a baffle seal as described above.
mountainskier89@reddit
In Alaska there’s been a surplus of carb icing issues recently
Whompner@reddit
Flight school I attended was having problems with their R44 Lycoming engines getting stuck valves, very dry and dusty environment. Only time it happened to me was also in a 44 on engine startup years later
JimMc0@reddit
Whats the situation with engine overhauls, a long time ago I read that if a part passes inspection it gets zero houred and returned to service in another engine. So surely eventually metal fatigue will eventually cause that part to fail.
erik325i@reddit
Lots of heating/cooling cycles in training plane engines. I had a cylinder crack during a night flight with a student. Plane always got its 100hr inspections & annuals. Hours on the engine was below TBO. Was a modern G1000 172. Cylinder cracked, lost compression in that cylinder, rough running, etc. Diverted and landed.
classysax4@reddit
The statistic is that piston engines fail on average every 20k hours. Of course this doesn't count fuel mismanagement, which happens far more often.
Granite_burner@reddit
https://imgur.com/a/J4jrfAM
ChazR@reddit
A lot of it is poor fuel management. Too much air or water in the tanks.
Then it's down to engine design and maintenance. Most GA aircraft are powered by engines designed - and sometimes built - in the dark ages of internal combustion. They use carburettors and magneto ignition. They have complex push-rod valve actuation.
These engines are missing out on 50-70 years of iterative and revolutionary improvement in design. A modern fuel-injected OHC engine with electronic ignition is going to be way more reliable and need less questionably-performed maintenance than an engine that has its soul in the 1950s.
But mostly it's fuel mismanagement.
guynamedjames@reddit
Go buy "The Killing Zone: How and Why Pilots Die". It's a data driven analysis on the causes of aviation accidents, especially relatively low hour pilots. It's really useful as a CFI to be able to teach with data
MostNinja2951@reddit
It's also fraudulent nonsense where the entire premise falls apart once you use the correct statistical approach. The "killing zone" does not exist.
u/Chairboy also.
Chairboy@reddit
Seconded, and the curve it graphs where it actually gets worse for a while before improving is wild too. You can see the FAA Human Factors spelled out in the numbers like someone in The Matrix looking at one of those falling green-letter displays who sees "a blond".
redditburner_5000@reddit
Running out of gas.
TheTangoFox@reddit
Ain't got no gas
BobLoblawATX@reddit
Check them points?
Kon3v@reddit
Currently it's lycomming cylinders shitting themselves. But the last local ones here have been the engine case through bolts which never had a lifetime limit on them. Those were snapping the cylinder would then effectively unzip from the case and exit stage left.
videopro10@reddit
For all yall saying fuel, fuel mismanagement accounts for a little less than half of accidents due to the engine quitting.
odins_gungnir@reddit
Little less than half on something that can be planned/controlled seems like a significant amount of preventable accidents.
videopro10@reddit
well that wasn't the question.
Santos_Dumont@reddit
Not enough money was pumped into it.
nonoohnoohno@reddit
Lots of great answers here for GA already, but I'll add for experimental light sport and ultralights, unreliable 2 strokes frequently fail.
Some argue they're fine if you closely follow warm up procedures by the book, but the bottom line is people don't so 2 stroke engine outs are common.
Dbeaves@reddit
Mine was dual magneto failure. The new magneto was faulty from the factory. It failed at 300 hours. Not required to be check until 500 hours.
Most other people? Lack of fuel mostly.
chuckop@reddit
No/not enough oil
No fuel
Very occasionally mechanical failure (value, piston rod, etc) that results in loss of oil.
2airishuman@reddit
fuel starvation caused by fuel exhaustion
vtjohnhurt@reddit
Pilot error
xtalgeek@reddit
Fuel mismanagement Carb icing Poor maintenance Dumb luck - broken valve, con rod, crank, case, etc. not related to poor maintenance
Probably in that order.
Rich-Cut-8052@reddit
Exactly, usually fuel starvation. Fighting a head wind, don’t like landing at a strange field, home is only 10 miles away, didn’t want to actually dip the tanks (trusting the fuel gauges), etc. etc., happens all the time.
ApprehensiveVirus217@reddit
I don’t zyn, but I always dip.
cofonseca@reddit
Fuel starvation, magneto failure, low/no oil, blown cylinder.
Keep track of your fuel burn, check your pressure and temp gauges, and understand how to diagnose a rough engine. You’ll be fine. Fuel starvation is almost certainly the most common issue.
BigBadPanda@reddit
Bertorelli lays it down
californiasamurai@reddit
I pulled power idle when landing once and the engine quit. Throttle spring was fucked (172). I didn't even pull it that hard lol.
2 months later... Alternator failure and alt cb popped (on ground). All was fine.
3 months later... Stuck valve. Uh-oh, we can't go flying. Next day, engine died in the middle of a runup.
Cold Arizona weather and hot Florida weather? And student pilots beating the shit out of these poor planes?
Merican1973@reddit
Piston engines are literally beating themselves up when running. Various parts can fail and lead to total or partial power loss.
They are still very reliable but not nearly as reliable as turbines.
Articles about how an engine didn’t fail aren’t very exciting so you get to read about failures even though they are a small percentage of flights.
rFlyingTower@reddit
This is a copy of the original post body for posterity:
300hr cfi rant . Almost daily I come across another story or atc recording of a piston engine usually a Cherokee or Cessna having an emergency engine failure causing them to land off field …..if they’re lucky.
What are 100 hr maintenance checks missing? Is it just dumb luck? Are there signs you guys look for during run up besides obvious roughness or mag drops outside of the limits etc? Are there certain personal minimums you guys use on top required airworthiness for maintenance for planes being used for rent or hire?
I follow a lot of aviation pages online so maybe I’m just over exposed to all these engine failures but none of them seem to ever post a reason for the failure. I started flying a few months before the aopa guy who reviewed all these emergencies went down shortly after takeoff in a newer Cessna and was killed. That had always really stuck with me. If it can happen to the guy who dedicated the end of his professional career to keeping people safe it can really happen to anyone, anytime.
To piston engines just suck, what’s the deal?
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