Engine Failure Probability

RyanB

RyanB

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After reading about 2 accidents in the same day yesterday (DAB and Merritt Island FL) both saying engine failure was a likely cause. Does anyone know what the probability of an engine failure is? Any stats on this? Really gets me thinking when I see things like this.
 
It increases exponentially when you run out of fuel.
 
Ryanb said:
After reading about 2 accidents in the same day yesterday (DAB and Merritt Island FL) both saying engine failure was a likely cause. Does anyone know what the probability of an engine failure is? Any stats on this? Really gets me thinking when I see things like this.
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It's why so many of us fly near roads. And wonder about those that don't....
 
Ryanb said:
After reading about 2 accidents in the same day yesterday (DAB and Merritt Island FL) both saying engine failure was a likely cause. Does anyone know what the probability of an engine failure is? Any stats on this? Really gets me thinking when I see things like this.
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What Sac Arrow was trying to say is you are more likely to run out of fuel than have an engine failure.
 
Ryanb said:
After reading about 2 accidents in the same day yesterday (DAB and Merritt Island FL) both saying engine failure was a likely cause. Does anyone know what the probability of an engine failure is? Any stats on this? Really gets me thinking when I see things like this.
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There are about 4 million people injured and around 33,000 people killed in traffic accidents every year. I'm almost afraid to drive to the airport.
 
I read somewhere that most accidents happen within 3 miles of home.


That's why I might be moving soon...
 
flyingriki said:
It's why so many of us fly near roads. And wonder about those that don't....
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That pretty much takes the advantage of flying away if you have to follow roads.

It would also preclude seeing and visiting some amazing places in this country.


Not a life worth living if tied to roads.
 
Ryanb said:
After reading about 2 accidents in the same day yesterday (DAB and Merritt Island FL) both saying engine failure was a likely cause. Does anyone know what the probability of an engine failure is? Any stats on this? Really gets me thinking when I see things like this.
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It's small compared to doing something dumb (like running out of fuel). It can and does happen, and it's not always catastrophic, but the outcome depends a lot on keeping your wits and flying the airplane to as slow a landing (DON'T STALL) and as long a stop (G forces go up exponentially with deceleration rate) as possible given the circumstances.

And if it happens on takeoff and you're not at pattern altitude DO NOT TURN BACK TO THE RUNWAY. Always have a Plan B.

Don't pay too much attention to news reports, there is always some amount of inaccuracy and emotion in stories. Remember- "if it bleeds it leads".
 
I keep it simple...I don't think of it IF my engine will fail, but WHEN my engine will fail! When you expect it and it doesn't happen, it is a much more enjoyable flight than worrying IF it will fail!
 
JoseCuervo said:
That pretty much takes the advantage of flying away if you have to follow roads.

It would also preclude seeing and visiting some amazing places in this country.


Not a life worth living if tied to roads.
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You would rather kill yourself than follow a road?

A bit over the top, perhaps?

There is still a lot of advantage to flying. It's an 8 hour drive from San Francisco to Mammoth. It's a 1 1/2 hour flight on the same route, in a 177RG.
 
JOhnH said:
There are about 4 million people injured and around 33,000 people killed in traffic accidents every year. I'm almost afraid to drive to the airport.
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No kidding. I'll tell you that almost every time I drive to the airport some dumbass puts my life at at risk.
 
Shawn said:
I keep it simple...I don't think of it IF my engine will fail, but WHEN my engine will fail! When you expect it and it doesn't happen, it is a much more enjoyable flight than worrying IF it will fail!
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Good pilots are pessimists who are pleasantly surprised when everything goes right.
 
Ryanb said:
After reading about 2 accidents in the same day yesterday (DAB and Merritt Island FL) both saying engine failure was a likely cause. Does anyone know what the probability of an engine failure is? Any stats on this? Really gets me thinking when I see things like this.
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It depends on the level of fuel and oil available for use on departure. If you have most of the oil in the engine and 4 hours of fuel on a 3 hour trip, the likelihood of failure is quite low. If you take off after an oil change and forgot to refill, or have three hours fuel on a 4 hour flight, the likelihood is quite high.
 
JoseCuervo said:
That pretty much takes the advantage of flying away if you have to follow roads.

It would also preclude seeing and visiting some amazing places in this country.


Not a life worth living if tied to roads.
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You're allowed to cross them at oblique angles. :D
 
My uncle has 26,000 hours. I think he's had two (and he flew piston/turbine his entire career in the military).

My instructor had 6,000 hours (he spent a fair amount of that in jets) and he's never had one.

Seems to just be total luck of the draw.
 
Internal combustion engines are remarkably reliable. I have driven cars for 32 years, and I can't recall *ever* having the engine quit on me while driving (other than being out of fuel once or twice when I was young). Unable to start, but not just stopped while running. It surely happens, but it's very rare.

Airplane engines are simpler than car engines generally, but they also use older technology. Airplane engines run far fewer hours than car engines, but at a much higher percentage of their rated power. Overall, reliability might be a wash compared to car engines.

This assumes you maintain them and keep fuel and oil in them, of course...
 
Bonchie said:
My uncle has 26,000 hours. I think he's had two (and he flew piston/turbine his entire career in the military).

My instructor had 6,000 hours (he spent a fair amount of that in jets) and he's never had one.

Seems to just be total luck of the draw.
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Maintenance and listening to your engine, understanding what it's telling you goes a long way as well. Operating hard 75°-125° ROP where you are making best power and speed is tough on engines, especially turbocharged air cooled engines where you are producing a lot of heat and inner cylinder pressure without the cooling capacity due to lack of ambient air density to take the heat away. Running overly rich a lot will cause valve, seat, and guide issues, but typically not a full engine failure. Typically you will lose one cylinder and have a shaky engine, but really it will normally get caught on a compression test before you realize there is a problem.

Turbines have a different set of issues and are much more difficult for a pilot to break, but when a pilot manages to break them, boy howdy is it an expensive mistake lol. Typically it's an insured mistake.

There are also methods to operate recip engines that will reduce your costs from failures, maintenance, and fuel that people should really take advantage of. It's all about understanding how efficiently you can create and use the energy in the cylinder.

If you want to read 'The Authoritative Primmer on Recip Engine Management' read "The Lindbergh Doctrine". Lindbergh went down and flew with Chenault's Flying Tigers and showed them how to double their combat sortie and patrol range. The gist of it is you run the maximum manifold pressure and minimum RPM you can manage for the speed you need, the slower to around 1.3 L/D Max the better your range. When the war started for the US the Flying Tigers broke up and were sent back to fleet and AAF air wings and brought back the knowledge.
 
flyingriki said:
It's why so many of us fly near roads. And wonder about those that don't....
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Why do you think flying near roads makes you safer? They generally have power lines that you can't see until it's too late. Snag ones of those during a power-off landing and you're toast.
 
Eagle I said:
Why do you think flying near roads makes you safer? They generally have power lines that you can't see until it's too late. Snag ones of those during a power-off landing and you're toast.
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Lol, it depends! If you have your energy low enough, they can actually provide an interesting stop, as close to a carrier trap as a civilian will get.:lol:. People get pulled out of planes hanging from power lines on a not too infrequent basis. They're hanging upside down, but otherwise no worse for wear. Take it through the windshield and the rest of your day will be short, but that's not a given.

Every emergency is its own set of circumstances. There is nothing hard and fast in an emergency, you look at what your hand is and play it as best you can and hope your bluff works. That's why the FAA doesn't tell you what to do, they just tell you "Go ahead and do whatever you have to do to ensure a safe outcome, all rules are gone."

Sometimes following a road makes sense, sometimes traversing a ridgeline in the lift makes more sense. There's always variables to deal with that you will not know ahead of time. As a pilot you always have to remain flexible in your choice of options to maximize your odds and minimize your risks as the prevailing conditions dictate. Be the ball Danny.
 
Eagle I said:
Why do you think flying near roads makes you safer? They generally have power lines that you can't see until it's too late. Snag ones of those during a power-off landing and you're toast.
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Like what happened to the Piper Archer guy with the daughter and friend flying from Chicago to Florida via Tennesse. Clipped the power line looking to put it down on a road and scalped them. Roads are bad places to put airplanes without having prior knowledge of the presence [or lack thereof] and layout of powerlines.
 
bullwinkle said:
Internal combustion engines are remarkably reliable. I have driven cars for 32 years, and I can't recall *ever* having the engine quit on me while driving (other than being out of fuel once or twice when I was young).
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I have lost two water pumps in cars over the years. The bearing made such a racket it was impossible to ignore, warning me to limp home before complete failure.

To the OP: Airplane engines will also tell you when something is wrong, but you have to listen and watch for the signs of a problem. It is seldom as obvious as a howling bearing.

-Skip
 
bullwinkle said:
Internal combustion engines are remarkably reliable. I have driven cars for 32 years, and I can't recall *ever* having the engine quit on me while driving (other than being out of fuel once or twice when I was young). Unable to start, but not just stopped while running. It surely happens, but it's very rare.

Airplane engines are simpler than car engines generally, but they also use older technology. Airplane engines run far fewer hours than car engines, but at a much higher percentage of their rated power. Overall, reliability might be a wash compared to car engines.

This assumes you maintain them and keep fuel and oil in them, of course...
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If you lose your electrical system, your car engine will quit. This is MUCH more likely than you seem to think. While a dead alternator will give plenty of warning, a blown point set or ignition module will fail without warning. A broken engine block or head ground can do that as well. I had a pigtail ground break while I was driving the VW, and it kept running until the now-overloaded fuel pump ground burned out. The warning was a few seconds of "what's that smell?" coming from the back of the fuse block before the fuel was cut off. Then, I discovered it would ground through the parking brake, so it ran fine as long as the BRAKE light was illuminated. Interesting day….

An aircraft engine will generally continue happily regardless of the state of the electrical system. At least outside the realm of FADEC and turbine applications.
 
Eagle I said:
Why do you think flying near roads makes you safer? They generally have power lines that you can't see until it's too late. Snag ones of those during a power-off landing and you're toast.
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You don't have to land ON the road.

If there is no road nearby and you land perfectly, now you have a survival situation. You may need to walk out. Which can be really difficult if you have sustained even light injuries. Every try to hike on a sprained ankle?
 
MAKG1 said:
You don't have to land ON the road.

If there is no road nearby and you land perfectly, now you have a survival situation. You may need to walk out. Which can be really difficult if you have sustained even light injuries. Every try to hike on a sprained ankle?
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Missing a lot of the best parts of the country if afraid to leave the roads and civilization.

Best times in life aren't near roads.
 
personally, about once every 11-1200 hours I've had an engine or prop problem that either shut down the engine or caused me to shut it down. That includes ferry flights of dormant planes and testing of new homebuilts.
 
MAKG1 said:
You would rather kill yourself than follow a road?

A bit over the top, perhaps?

There is still a lot of advantage to flying. It's an 8 hour drive from San Francisco to Mammoth. It's a 1 1/2 hour flight on the same route, in a 177RG.
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Landing on a road, especially the typical highway, can get you killed quicker than putting it in the trees. Cars and trucks aren't expecting something to appear from above. And if you cause an accident while doing so, the lawyers get all excited and rub their hands together.

Dan
 
Ryanb said:
After reading about 2 accidents in the same day yesterday (DAB and Merritt Island FL) both saying engine failure was a likely cause. Does anyone know what the probability of an engine failure is? Any stats on this? Really gets me thinking when I see things like this.
Click to expand...
No direct stats, but we can do some estimation.

From the year 2001 to 2010, 182 Cessna 172s had accidents that involved engine failure. Almost exactly half (90) were due to mechanical issues. Keep in mind that some planes experienced engine failures but did not result in a reportable accident. That's an average of nine accidents per year.

At the beginning of the period (30 Dec 2000) there were 25,807 Cessna 172s; at the end (31 Dec 2010) there were 25,934. That's an average of 25870 aircraft.

So...during a given year, about 0.03% of Cessna 172s have an accident due to mechanical failure of the engine.

Offhand, it seems safe....

Ron Wanttaja
 
Skip Miller said:
I have lost two water pumps in cars over the years. The bearing made such a racket it was impossible to ignore, warning me to limp home before complete failure.

To the OP: Airplane engines will also tell you when something is wrong, but you have to listen and watch for the signs of a problem. It is seldom as obvious as a howling bearing.

-Skip
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Yeah, I have had similar. If you pay attention, it's rare an engine (with fuel) will just quit out of the blue.
 
Capt. Geoffrey Thorpe said:
I'm confidant that there is no reliable source of a valid statistic.
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Me, too. But in reading the accident reports involving engine failure, pretty much all of them seem to involve stupidity, either in the maintenance or the operation of the aircraft. My experience suggests that the chances of an engine quitting are awfully low if it's properly maintained and operated (including fuel management).
 
Road vs. not road.

The definitive answer is: "It depends."

One of the old man's partners put their Navion down in a field (broken crank as a result of a problem with the counterweights - the pilot noticed that it seemed rough, but flew it anyhow). I helped move the airplane down a two lane country road to a better farm strip where it got fixed and flown out. The field was by far the better choice in this case. Even just towing the airplane was difficult due to all of the obstructions along the sides of the road.

Another aircraft that the old man had sold was departing from what is now VLL and lost power on takeoff (blamed on auto fuel in an aircraft not approved for auto fuel by the NTSB ) and put it down on the rail road tracks (about the only open area there is). Occupants were OK, but the aircraft was totaled.

A few years ago, someone lost power in a Cessna 150 (don't know why) near the intersection of Southfield Road (M-39) and I-75 just downriver from Detroit. Urban area, not many options. The pilot passed up a school field (Lincoln Park High School) over concerns that there would be children playing there and attempted to reach some vacant land further south. He didn't have enough altitude to make it there (and the field he was trying for is an antenna farm) and ended up successfully merging with rush hour traffic on southbound I-75.

Every situation is unique and you try and pick the least stupid option that is available.
 
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