The Probability of an Engine Failure in a Certified GA SEP
Thread Starter
And it's worth remembering that if you really did get the speed wrong for your selected landing spot, you'd rather cross the near fence too fast, and not be able to stop for the far one, than to not make it over the near one, and crash into something at speed, without the opportunity to get the plane on the ground, and slow down for a while.
.
When it suddenly goes quiet, decisions must be made with little head scratching - 'cause your thinking, planning skill and experience have covered most of the factors
Is maths allowed?
Number of GA departures / number of GA EFATO? (you can pick your timescale "per day/month/year")
I suspect the result is an extremely small number.
Not zero, but...
Then, another sum:
Number of GA PFL / number of GA PFL that end up going wrong and end up on the ground
Also a very small number, but just might be higher than the first answer.
Just a thought...
Number of GA departures / number of GA EFATO? (you can pick your timescale "per day/month/year")
I suspect the result is an extremely small number.
Not zero, but...
Then, another sum:
Number of GA PFL / number of GA PFL that end up going wrong and end up on the ground
Also a very small number, but just might be higher than the first answer.
Just a thought...
Join Date: Apr 2003
Location: Midlands
Posts: 2,359
Likes: 0
Received 0 Likes
on
0 Posts
After my first engine failure back in the 90's I did an analysis of 6 or 7 years worth of engine failure data. About 50% were no significant damage or injury, about 25% was no significant injury but significant damage to the aircraft. The remaining 25% were significant injury or death plus serious damage. I regularly do PFL's and do not think I would be around to debate on the forum if I had not.
Rod1
Rod1
Thread Starter
A lot of the posts on this thread seem imply that I am advocating ignoring the requirement to be proficient in handling a PFL. If that message came across from what I have written than it was not my intent.
Instead I would like to re-emphasize that I believe dealing with an engine failure starts with taking objective measures to minimize the risk of the engine failing in the first place, as actions or inactions of the pilot is cause of the majority of engine failures.
Following that is thinking of and practicing the vital actions drills that will restore power, if practicable and obviously not applicable to a EFATO, and then yes practicing the power off glide path judgement that is obviously vital to a successful arrival after an engine failure. Of note you don't have to do a PFL to do that, simply when traffic and local airport procedures allows, make your landings start with closing the throttle at various points in the circuit.
Finally a safe pilot has to be proficient at every part of flying, not just doing PFL's. The accident record clearly shows that the majority of bent metal are landing and takeoff accidents that are a result of a lack of skill on the part of the pilot.
I think the whole engine failure thing feeds the secret hero pilot fantasy lurking in almost everyone. "There I was minding my own business when BAMM the engine blew up. But I did not panic and side slipped the little sucker into that postage stamp field rolling to a stop with no damage to the airplane ! "
The "my vigilance at doing a comprehensive pre flight check caught the build up of carb ice as I was waiting to takeoff and thus prevented the EFATO" is a lot less sexy, but ultimately represents a narrative just as important, if not more important, as the first one....
Instead I would like to re-emphasize that I believe dealing with an engine failure starts with taking objective measures to minimize the risk of the engine failing in the first place, as actions or inactions of the pilot is cause of the majority of engine failures.
Following that is thinking of and practicing the vital actions drills that will restore power, if practicable and obviously not applicable to a EFATO, and then yes practicing the power off glide path judgement that is obviously vital to a successful arrival after an engine failure. Of note you don't have to do a PFL to do that, simply when traffic and local airport procedures allows, make your landings start with closing the throttle at various points in the circuit.
Finally a safe pilot has to be proficient at every part of flying, not just doing PFL's. The accident record clearly shows that the majority of bent metal are landing and takeoff accidents that are a result of a lack of skill on the part of the pilot.
I think the whole engine failure thing feeds the secret hero pilot fantasy lurking in almost everyone. "There I was minding my own business when BAMM the engine blew up. But I did not panic and side slipped the little sucker into that postage stamp field rolling to a stop with no damage to the airplane ! "
The "my vigilance at doing a comprehensive pre flight check caught the build up of carb ice as I was waiting to takeoff and thus prevented the EFATO" is a lot less sexy, but ultimately represents a narrative just as important, if not more important, as the first one....
Join Date: Sep 2006
Location: 23, Railway Cuttings, East Cheam
Age: 68
Posts: 3,115
Likes: 0
Received 0 Likes
on
0 Posts
Number of GA PFL / number of GA PFL that end up going wrong and end up on the ground
Also a very small number, but just might be higher than the first answer.
Also a very small number, but just might be higher than the first answer.
Join Date: Jan 2008
Location: Canada
Posts: 631
Likes: 0
Received 0 Likes
on
0 Posts
But I did not panic and side slipped the little sucker into that postage stamp field rolling to a stop with no damage to the airplane !
The skills to prevent unplanned events are of great importance, but they are not the same skills as those applied to dealing with them. Yes, if I'd poured alcohol into the fuel tanks, two of those glides probably would not have had to be flown so adequately. Preparation skills are intellectual, and largely ground training. Dealing with the sudden silence is muscle memory stuff....
So, the probability of an EFATO goes way up with poor preparation for the flight. But, the EFATO has to be one of the most challenging events to demand judgement and skill instantly, and all the way to the ground. It's worth the regular practice. Luckily, I fly mostly at very quiet airports, so PFL's from the circuit are common for me. Those times I have to sneak in some power on the base to final turn, tell me that I'm not practicing enough!
A few years back, I had to fly a few maintenance check flights on a Tiger Moth, which had not flown in a decade. I flew the entire circuit as an impending EFATO - because honestly, I have never glided a Tiger Moth, and did not have the muscle memory to handle it well!
When I'm training pilots, I'm one of those annoying mentors who first says to fly a more close in downwind, and then at the right point I'll say "you can make it to the runway" as I gently pull the power to idle.
Join Date: Jan 2008
Location: Canada
Posts: 631
Likes: 0
Received 0 Likes
on
0 Posts
Most engine failure causes can be at least mitigated by effective preflight checks, and pilot behaviour. So, yes, good preflights, and pre takeoff techniques.
However, I have had one total failure, and two major power losses, whose causes were entirely mechanical (not poor maintenance) related. So, patting yourself on the back for an awesome preflight, and operating technique to the "position and hold" point, should not cause you to relax your guard for an EFATO,
Two causal factors I have had: Stuck exhaust valve just after liftoff. The engine does not stop, but you sure think it's going to, while you struggle to climb out at less than 75% power. And, a mouse nest of fibreglass insulation from under the instrument panel, being sucked up a hot air hose into the carburettor venturi. That one put me into the field off the end of my runway!
However, I have had one total failure, and two major power losses, whose causes were entirely mechanical (not poor maintenance) related. So, patting yourself on the back for an awesome preflight, and operating technique to the "position and hold" point, should not cause you to relax your guard for an EFATO,
Two causal factors I have had: Stuck exhaust valve just after liftoff. The engine does not stop, but you sure think it's going to, while you struggle to climb out at less than 75% power. And, a mouse nest of fibreglass insulation from under the instrument panel, being sucked up a hot air hose into the carburettor venturi. That one put me into the field off the end of my runway!
Join Date: Jan 2011
Location: Gone
Posts: 1,665
Likes: 0
Received 0 Likes
on
0 Posts
Statistics suggest that all the best pre flight inspections in the world will not significantly reduce EFATO as they are all generally mechanically based.
I've had two piston engine failures. First reason was broken piston ring that smashed up the engine. Second reason unknown cause as I had to ditch in the Channel.Suspect a hole through side of the engine as oil was smelt.
I've had two piston engine failures. First reason was broken piston ring that smashed up the engine. Second reason unknown cause as I had to ditch in the Channel.Suspect a hole through side of the engine as oil was smelt.
Join Date: Oct 2001
Location: Vancouver Island
Posts: 2,517
Likes: 0
Received 0 Likes
on
0 Posts
Statistics suggest that all the best pre flight inspections in the world will not significantly reduce EFATO as they are all generally mechanically based.
Join Date: Jan 2008
Location: Canada
Posts: 631
Likes: 0
Received 0 Likes
on
0 Posts
Chuck... That instructor has a point... Actually, 10 out of 10 EFATO's are pilot caused - 'cause they would not happen if pilots were not trying to do point things with planes! 
Join Date: Apr 2003
Location: Midlands
Posts: 2,359
Likes: 0
Received 0 Likes
on
0 Posts
Having asked around locally, most of us who have had engine failure had mechanically based issues or fuel. Mechanical issues included crank failure, mag failure, prop disintegrating after stone damage on takeoff, bird through canopy, oil pipe fail covering canopy with oil. Fuel was all around vapor lock or blockage in the system, one pipe / valve split. I am a big fan of know your aircraft and check it before flight (I built mine), but I am not convinced that many of the above could have been spotted on the ground by an average PPL with normal piloting kit.
crank failure - no chance
mag failure - no chance
prop disintegrating after stone damage on takeoff - no chance
bird through canopy - no chance
oil pipe fail covering canopy with oil - probably no chance
vapor lock - probably yes - know your aircraft
Fuel blockage - No chance
Fuel pipe / valve split - probably not
Rod1
), but I am not convinced that many of the above could have been spotted on the ground by an average PPL with normal piloting kit.crank failure - no chance
mag failure - no chance
prop disintegrating after stone damage on takeoff - no chance
bird through canopy - no chance
oil pipe fail covering canopy with oil - probably no chance
vapor lock - probably yes - know your aircraft
Fuel blockage - No chance
Fuel pipe / valve split - probably not
Rod1
Join Date: Oct 2001
Location: Vancouver Island
Posts: 2,517
Likes: 0
Received 0 Likes
on
0 Posts
These discussions tend to drift all over the place Step Turn.
There are a few mistakes that pilots make before take off that can cause the engine to fail right after take off.
Failure to select a tank with fuel in it.
Carb ice
Water in the fuel.
The other killer is taking off with control locks on / engaged.
These discussions are interesting and there are a lot of things that are useful to remember, however flying light single engine airplanes safely is well within the ability of the average person in our society.
Sometimes over thinking these things is just as bad as not thinking.
There are a few mistakes that pilots make before take off that can cause the engine to fail right after take off.
Failure to select a tank with fuel in it.
Carb ice
Water in the fuel.
The other killer is taking off with control locks on / engaged.
These discussions are interesting and there are a lot of things that are useful to remember, however flying light single engine airplanes safely is well within the ability of the average person in our society.
Sometimes over thinking these things is just as bad as not thinking.
Thread Starter
The sole purpose of this post seems to be to heap ridicule on the premise of my my thread. I find that rather disappointing...
Thread Starter
Unfortunately it is simply not true. If you do not believe me just go and review the last 5 years worth of AAIB or NTSB accident summaries. If you do that you will find lots of fuel exhaustion/fuel mismangement/fuel contamination/engine mismangement/carb ice caused accidents but not very many where the engine failed due to a mechanical failure of the engine itself or an engine accessory. And even those often involved flying an engine with a known fault.
I will add a caveat. As I mentioned earlier I am talking about simple Lycoming or Continental engines, or the engines I believe most of the readers of this forum are flying behind. Older 2 stroke microlight engines and some of the weirder car engine conversions ( not the good VW conversions) as well as various pre WW 2 early aero engine designs have a horrendous record of inflight failures due to mechanical failures and so obviously the 80 % pilot caused number does not apply to those.
Personally I think it is much more palatable to us pilots to believe the myth that most forced approaches are the result of a mechanical failure that the pilot could not reasonably have foreseen. It is a lot more uncomfortable to think about the fact that a lot of airplanes are needlessly wrecked because the pilot failed to adequately pay attention to the basics, like making sure there was enough uncontaminated fuel with the fuel selector correctly set, or not allowing carburetor ice to develop to such an extent that the engine stopped.
The first step in reducing the number of crashed aircraft is to understand where the problem is, and it is not perfectly good engines suddenly stopping because of mechanical failures. Unfortunately that is almost always the starting point of the discussion, training, and practicing of the engine failure scenario.
If one person reads this and realizes that maybe they were a little lax on some of the cockpit good house keeping and makes a permanent change in how they are operating their aircraft, I will be happy as there will be at least one pilot who will be less likely to cause an aircraft to be needlessly bent.
Last edited by Big Pistons Forever; 23rd Mar 2015 at 23:27.
Thread Starter
Having asked around locally, most of us who have had engine failure had mechanically based issues or fuel. Mechanical issues included crank failure, mag failure, prop disintegrating after stone damage on takeoff, bird through canopy, oil pipe fail covering canopy with oil. Fuel was all around vapor lock or blockage in the system, one pipe / valve split. I am a big fan of know your aircraft and check it before flight (I built mine), but I am not convinced that many of the above could have been spotted on the ground by an average PPL with normal piloting kit.
crank failure - no chance
mag failure - no chance
prop disintegrating after stone damage on takeoff - no chance
bird through canopy - no chance
oil pipe fail covering canopy with oil - probably no chance
vapor lock - probably yes - know your aircraft
Fuel blockage - No chance
Fuel pipe / valve split - probably not
Rod1
), but I am not convinced that many of the above could have been spotted on the ground by an average PPL with normal piloting kit.crank failure - no chance
mag failure - no chance
prop disintegrating after stone damage on takeoff - no chance
bird through canopy - no chance
oil pipe fail covering canopy with oil - probably no chance
vapor lock - probably yes - know your aircraft
Fuel blockage - No chance
Fuel pipe / valve split - probably not
Rod1
2 fuel exhaustion ( C 150 , C 172)
2 mis managed fuel selector ( Pa 28 C 172)
2 Carb ice ( C 150, Aeronca Champ)
1 Catastrophic engine failure after a connecting rod broke ( C 172)
As should be rather obvious as a pilot and flying instructor I am very interested in the engine failure scenario in light aircraft.
I would appreciate some more detail on the incidents you described.
Specifically
-Mag failure. Was this a dual simultaneous failure ?
- Prop disintegrating after stone damage. Was the prop damaged prior to the takeoff or did it hit a rock on the takeoff roll ?
- Bird through the canopy. How did this cause the engine to fail ?
Join Date: Jan 2008
Location: Canada
Posts: 631
Likes: 0
Received 0 Likes
on
0 Posts
The sole purpose of this post seems to be to heap ridicule on the premise of my my thread.
Join Date: Apr 2003
Location: Midlands
Posts: 2,359
Likes: 0
Received 0 Likes
on
0 Posts
-Mag failure. Was this a dual simultaneous failure ?
- Prop disintegrating after stone damage. Was the prop damaged prior to the takeoff or did it hit a rock on the takeoff roll ?
- Bird through the canopy. How did this cause the engine to fail ?
Not all mine so details only on some;
Mag failure Robin DR400 C of A aircraft 160hp Lyk
I noticed an increase in fuel consumption 9 months before the incident. Maintenance organization checked everything NFF sent me the bill. I persisted - they sent the carb off to be checked, NFF. Real problem was poorly mag wiring which was breaking down when hot. Good Mag failed leaving me with a very unhappy engine and a lot of vibration. Landed with no damage
"Prop disintegrating after stone damage. Was the prop damaged prior to the takeoff or did it hit a rock on the takeoff roll ?"
Not mine but I understand there was a bang just as he got airborne off a short strip. All normal for about 20 sec then the prop tip came off. Damage from stone obvious on later inspection. Pilot had to shut off all power due to huge vibration. Landed without incident.
"Bird through the canopy. How did this cause the engine to fail ? "
No further info. Aircraft overturned in soft ground but at relatively slow speed. (again not one of mine).
This is from a group of experienced pilot owners which may be relevant?
Rod1
- Prop disintegrating after stone damage. Was the prop damaged prior to the takeoff or did it hit a rock on the takeoff roll ?
- Bird through the canopy. How did this cause the engine to fail ?
Not all mine so details only on some;
Mag failure Robin DR400 C of A aircraft 160hp Lyk
I noticed an increase in fuel consumption 9 months before the incident. Maintenance organization checked everything NFF sent me the bill. I persisted - they sent the carb off to be checked, NFF. Real problem was poorly mag wiring which was breaking down when hot. Good Mag failed leaving me with a very unhappy engine and a lot of vibration. Landed with no damage
"Prop disintegrating after stone damage. Was the prop damaged prior to the takeoff or did it hit a rock on the takeoff roll ?"
Not mine but I understand there was a bang just as he got airborne off a short strip. All normal for about 20 sec then the prop tip came off. Damage from stone obvious on later inspection. Pilot had to shut off all power due to huge vibration. Landed without incident.
"Bird through the canopy. How did this cause the engine to fail ? "
No further info. Aircraft overturned in soft ground but at relatively slow speed. (again not one of mine).
This is from a group of experienced pilot owners which may be relevant?
Rod1
Last edited by Rod1; 24th Mar 2015 at 12:26.
Thread Starter
-Mag failure. Was this a dual simultaneous failure ?
- Prop disintegrating after stone damage. Was the prop damaged prior to the takeoff or did it hit a rock on the takeoff roll ?
- Bird through the canopy. How did this cause the engine to fail ?
Not all mine so details only on some;
Mag failure Robin DR400 C of A aircraft 160hp Lyk
I noticed an increase in fuel consumption 9 months before the incident. Maintenance organization checked everything NFF sent me the bill. I persisted - they sent the carb off to be checked, NFF. Real problem was poorly mag wiring which was breaking down when hot. Good Mag failed leaving me with a very unhappy engine and a lot of vibration. Landed with no damage
"Prop disintegrating after stone damage. Was the prop damaged prior to the takeoff or did it hit a rock on the takeoff roll ?"
Not mine but I understand there was a bang just as he got airborne off a short strip. All normal for about 20 sec then the prop tip came off. Damage from stone obvious on later inspection. Pilot had to shut off all power due to huge vibration. Landed without incident.
Rod1
- Prop disintegrating after stone damage. Was the prop damaged prior to the takeoff or did it hit a rock on the takeoff roll ?
- Bird through the canopy. How did this cause the engine to fail ?
Not all mine so details only on some;
Mag failure Robin DR400 C of A aircraft 160hp Lyk
I noticed an increase in fuel consumption 9 months before the incident. Maintenance organization checked everything NFF sent me the bill. I persisted - they sent the carb off to be checked, NFF. Real problem was poorly mag wiring which was breaking down when hot. Good Mag failed leaving me with a very unhappy engine and a lot of vibration. Landed with no damage
"Prop disintegrating after stone damage. Was the prop damaged prior to the takeoff or did it hit a rock on the takeoff roll ?"
Not mine but I understand there was a bang just as he got airborne off a short strip. All normal for about 20 sec then the prop tip came off. Damage from stone obvious on later inspection. Pilot had to shut off all power due to huge vibration. Landed without incident.
Rod1
After an uneventful return to my home airport the problem was diagnosed as an internal failure of a mag gear. This caused the spark on that mag to advance 20 deg
. The engine did not at all like the dueling mags and therefore ran like shyte. However switching to one mag instantly restored what was effectively full power. I raise this because it is an inflight troubleshooting trick that does not seem to be often covered in flight training.Obviously In my case I was in cruise so I had lots of time to methodically troubleshoot. You don't want to faffing around switching mags in the EFATO scenario, just concentrate on flying the aircraft to a safe arrival.
With respect to the prop. I don't want to sound rude here, and obviously I am looking at this at 3 rd hand distance, but frankly I am a bit skeptical that a perfectly sound prop hits a rock and flies apart. I suspect that the prop already had a few big dings in it and the rock was the final straw.
Anyway the the bottom line is the importance of a good preflight check of the prop and getting any dings immediately dressed out before they could affect the structural integrity of the prop.