ok multis are a double edged sword, more performance but more risk to mitigate. They are of a time before single turbines were available to the GA pilot. Nonetheless, examination of the AOPA published “lethality rates” for accidents in the mechanical related category shows a lot of variation from year to year in the multi fleet (law of small numbers). Some years multi engines are less lethal, but most often they are more so. Averaged over 10 years (2010 - 2019 to avoid covid) you get this: Mechanical related SE: 7.5% lethality rate (that is % of accidents that are lethal) Mechanical related ME: 13% The multi is more lethal after mechanical failure accidents, of which engines are the dominant subset. As expected. But examination of lethality rates for all causes reveals something: All SE: 14.1% All ME: 30.8% The multi is even more lethal when you include all the types of accident that are not related to engine failure. That is the opposite of what should happen if the extra lethality was associated with failure of the extra engine. Hmm. So I looked at complex singles and found their lethality to be halfway between SE and ME on mechanical related accidents, whilst for ‘all causes’ they move much closer to ME (26.3 v 30.8). Again, this divergence from the wider single engine fleet cannot be engine related. To my mind all this implies that increased lethality is better attributed to higher power, faster, heavier, more complex airplanes with more occupants, that are operated more at night/IMC. This rather than just engine failure per se. And it is worth saying, not only the multi but also the high powered single too, would do even worse without the extra training.
The propeller is actuated by oil pressure. If the engine isn't turning fast enough, you may not have enough oil pressure to feather. If the engine seizes, you're not going to feather. This isn't as horrible a situation as it may seem as a stopped prop produces much less drag than a windmilling prop.
…the reason is that during a normal shutdown on the ground you don’t want the prop to go into feather after the oil pressure drops because it will shake like hell on the next start. Hence the anti feather lock pins. Bear in mind that with the constant speed prop you always have oil pressure acting against spring pressure to effect the pitch change. But there is an important difference between feathering prop (twins) and non-feathering prop (singles): the spring pushes toward feather (or coarse pitch) for twins whilst it pushes toward fine pitch on singles. This is logical because you want the prop to feather after engine failure on a twin, whereas you do not have asymmetric thrust to worry about in a single and it is better to be at fine pitch for the restart attempt. As a result of this spring action you need those anti feather lock pins to prevent the feathering on normal shutdown of a twin. Equally, it is highly desirable to have an unfeathering accumulator to ‘push back’ against that big spring before attempting to restart after feathering the prop. Finally, the single suffers a penalty in glide range for being in fine pitch, but windmilling rpm still provides sufficient oil pressure to move the prop into coarse pitch if the restart is unsuccessful.
Because you're landing at a faster airspeed. The ref speed on short final is Vyse (higher than normal) and you typically land with a lower flap setting on one engine.
Controlled or uncontrolled airport, flying a normal circuit including flying overhead makes no sense from a safety perspective. Regardless of which engine has failed, which is the critical one and not, a long, stabilized straight-in approach is better. Give yourself lots of distance (and time) to configure and establish the appropriate descent. You do not want to have to go around! I would also suggest using all available tools including PAPI and a vertically guided instrument approach, if available. This could be your one big chance to be a hero. You don’t get any points for making the situation more difficult than what it already is.
@@jeffg7 Never said you can't, but the more conservative approach, especially in a powerful ME, is to turn into the good engine. Turning into the "out engine" requires a wider pattern and a little finesse.
@@nothingtoseehere4026 Kind of. It's actually easier to turn into the out engine so it's easier to over control with rudder. IMO, it's not enough of a risk to, say, blow into an uncontrolled airport and fly a non standard pattern to avoid it. That's merely a judgement call.
@@jeffg7 Again, it's an emergency.. If you're not disciplined enough to pull power on the good engine and show rudder control, turn into the good engine. Save lives.
According to the FAA Airplane Flying Handbook, it is perfectly acceptable to make turns toward the failed engine and the direction of the pattern is of “no consequence to performance and controllability”. No doubt, if you dig right down into the aerodynamics, you could point to some aspect that arguably favoured one or the other. Certainly, with any significant cross wind, I would favour the pattern that gave me the into wind component on base. This has the beneficial effect of keeping the turn more compact as well as reducing the heading change of your final turn (by 2 x final crab angle).
There is no reason other than the ego trip to fly a light twin. The economics don't make sense and the fatality rates for light twins are higher than the rates for single engines. In the 90's when I was instructing the fatality rate was 6 times higher that the single engine rate. Some of the reason were higher gross weights (aircraft energy), management of asymmetric thrust, higher passenger loads, system complexity, and others.
You are right. Makes no sense to think having two engines makes you safer. I hear people say this when flying over water. Just nonsense! Double fuel, double maintenance and greater chance to die in an engines failure.
It's a series of tradeoffs, as all such decisions are. Categorically stating that there's "no reason other than the ego trip" is fatally overstating your argument, such as it is.
I’d imagine that light twins came about with useless single engines that could barely lift the aircraft off the ground. Well if you had two useless engines, you’d get 80% more performance with a slightly heavier aircraft. That’s with them both running. Now in the days of decent engine options (lycoming has left the conversation), you can do really well on one. I’d rather one decent engine than two rubbish engines. Now two decent engines are an even better option, but at that point, you’re in a King Air (honourable mention of the DA-42)
@@streptokokke1003 yes I looked before replying. I watched the whole video. Now if you look again at your time stamp you can see in the very bottom right of the frame another switch also labelled “MAG RIGHT”. This other ‘mag right’ switch is for the right mag of the number two engine (or right engine if you prefer). In that particular cockpit, the mag switches for each engine are grouped to their respective sides of the switch labelled “L START R”. Each engine has a left and right mag of its own. What you are being shown in the video is the switching off of both mags of one engine. You are not being shown the switching off of the mags of both engines.
Still working on my PPL, but hope to get a mutli engine rating someday. This video makes it sound like - more engines = more problems.
a twin merely doubles the probability of having an engine failure
ok multis are a double edged sword, more performance but more risk to mitigate. They are of a time before single turbines were available to the GA pilot. Nonetheless, examination of the AOPA published “lethality rates” for accidents in the mechanical related category shows a lot of variation from year to year in the multi fleet (law of small numbers). Some years multi engines are less lethal, but most often they are more so. Averaged over 10 years (2010 - 2019 to avoid covid) you get this:
Mechanical related SE: 7.5% lethality rate (that is % of accidents that are lethal)
Mechanical related ME: 13%
The multi is more lethal after mechanical failure accidents, of which engines are the dominant subset. As expected. But examination of lethality rates for all causes reveals something:
All SE: 14.1%
All ME: 30.8%
The multi is even more lethal when you include all the types of accident that are not related to engine failure. That is the opposite of what should happen if the extra lethality was associated with failure of the extra engine. Hmm. So I looked at complex singles and found their lethality to be halfway between SE and ME on mechanical related accidents, whilst for ‘all causes’ they move much closer to ME (26.3 v 30.8). Again, this divergence from the wider single engine fleet cannot be engine related.
To my mind all this implies that increased lethality is better attributed to higher power, faster, heavier, more complex airplanes with more occupants, that are operated more at night/IMC. This rather than just engine failure per se. And it is worth saying, not only the multi but also the high powered single too, would do even worse without the extra training.
I grew up near KSME. Pretty cool to see it from above!
Very helpful. Thank you!
Great presentation. If only I could be so calm when things go awry... 😉
So the engine has to be above a certain RPM to feather the propeller? Why is that? Seems dangerous given that an engine can seize.
Maybe because of the feather lock kicking in at lower rpms
The propeller is actuated by oil pressure. If the engine isn't turning fast enough, you may not have enough oil pressure to feather. If the engine seizes, you're not going to feather. This isn't as horrible a situation as it may seem as a stopped prop produces much less drag than a windmilling prop.
…the reason is that during a normal shutdown on the ground you don’t want the prop to go into feather after the oil pressure drops because it will shake like hell on the next start. Hence the anti feather lock pins.
Bear in mind that with the constant speed prop you always have oil pressure acting against spring pressure to effect the pitch change. But there is an important difference between feathering prop (twins) and non-feathering prop (singles): the spring pushes toward feather (or coarse pitch) for twins whilst it pushes toward fine pitch on singles. This is logical because you want the prop to feather after engine failure on a twin, whereas you do not have asymmetric thrust to worry about in a single and it is better to be at fine pitch for the restart attempt.
As a result of this spring action you need those anti feather lock pins to prevent the feathering on normal shutdown of a twin. Equally, it is highly desirable to have an unfeathering accumulator to ‘push back’ against that big spring before attempting to restart after feathering the prop.
Finally, the single suffers a penalty in glide range for being in fine pitch, but windmilling rpm still provides sufficient oil pressure to move the prop into coarse pitch if the restart is unsuccessful.
How would an airplane landing on 1 engine take up more runway than landing an airplane with both engines?
Because you're landing at a faster airspeed. The ref speed on short final is Vyse (higher than normal) and you typically land with a lower flap setting on one engine.
@@jeffg7 thank you for explaining it.
Controlled or uncontrolled airport, flying a normal circuit including flying overhead makes no sense from a safety perspective. Regardless of which engine has failed, which is the critical one and not, a long, stabilized straight-in approach is better. Give yourself lots of distance (and time) to configure and establish the appropriate descent. You do not want to have to go around!
I would also suggest using all available tools including PAPI and a vertically guided instrument approach, if available.
This could be your one big chance to be a hero. You don’t get any points for making the situation more difficult than what it already is.
It's already an emergency. If you're not able to go straight in, choose the downwind that allows you to turn into the good engine.
This is a myth. You have to take a little more care turning into the inoperative engine but it's not less safe than turning into the operative engine.
@@jeffg7 Never said you can't, but the more conservative approach, especially in a powerful ME, is to turn into the good engine. Turning into the "out engine" requires a wider pattern and a little finesse.
@@nothingtoseehere4026 Kind of. It's actually easier to turn into the out engine so it's easier to over control with rudder. IMO, it's not enough of a risk to, say, blow into an uncontrolled airport and fly a non standard pattern to avoid it. That's merely a judgement call.
@@jeffg7 Again, it's an emergency.. If you're not disciplined enough to pull power on the good engine and show rudder control, turn into the good engine. Save lives.
According to the FAA Airplane Flying Handbook, it is perfectly acceptable to make turns toward the failed engine and the direction of the pattern is of “no consequence to performance and controllability”. No doubt, if you dig right down into the aerodynamics, you could point to some aspect that arguably favoured one or the other. Certainly, with any significant cross wind, I would favour the pattern that gave me the into wind component on base. This has the beneficial effect of keeping the turn more compact as well as reducing the heading change of your final turn (by 2 x final crab angle).
I drive passenger buses. Very similar to flying aeroplanes. I call myself a bus-pilot.
There is a reason the “Spirit of St. Louis” was a single engine airplane
There is no reason other than the ego trip to fly a light twin. The economics don't make sense and the fatality rates for light twins are higher than the rates for single engines. In the 90's when I was instructing the fatality rate was 6 times higher that the single engine rate. Some of the reason were higher gross weights (aircraft energy), management of asymmetric thrust, higher passenger loads, system complexity, and others.
You are right. Makes no sense to think having two engines makes you safer. I hear people say this when flying over water. Just nonsense! Double fuel, double maintenance and greater chance to die in an engines failure.
Spoken like true professional and sensible pilots. Unless you're building twin time for an airline career, two engines are not needed.
It's a series of tradeoffs, as all such decisions are. Categorically stating that there's "no reason other than the ego trip" is fatally overstating your argument, such as it is.
@@blueocean9305 Night flying or over water makes it nice to fly a multi. If it's a multi with no power, can't climb on a single engine, no point.
I’d imagine that light twins came about with useless single engines that could barely lift the aircraft off the ground. Well if you had two useless engines, you’d get 80% more performance with a slightly heavier aircraft. That’s with them both running.
Now in the days of decent engine options (lycoming has left the conversation), you can do really well on one. I’d rather one decent engine than two rubbish engines. Now two decent engines are an even better option, but at that point, you’re in a King Air (honourable mention of the DA-42)
5:31: Shut off both Magnetos? Ok!
…it is a little ambiguous but they are saying turn off both magnetos of the dead engine rather than turn off the magnetos of both engines.
@@XPLAlNand now look what they show at the time stamp.
@@streptokokke1003 yes I looked before replying. I watched the whole video. Now if you look again at your time stamp you can see in the very bottom right of the frame another switch also labelled “MAG RIGHT”. This other ‘mag right’ switch is for the right mag of the number two engine (or right engine if you prefer). In that particular cockpit, the mag switches for each engine are grouped to their respective sides of the switch labelled “L START R”.
Each engine has a left and right mag of its own. What you are being shown in the video is the switching off of both mags of one engine. You are not being shown the switching off of the mags of both engines.