Agree that statistics are abused, especially variance analysis and accident probabilities, but using two conventions: fatalities over 100,000 hours, and % fatalities for each accident event, I stand by my earlier statement. I accept that it is several decades since I knew my autocorrelations from my heterodescasticities or kurtowsis, but the NTSB after five decades has a reasonable set of data.
In any event the twin piston new production has virtually gone the way of the dodo outside professional training and some specialist roles.
AdamFrisch wrote:
they’ll just continue to their destination
I thought that is exactly how you get into a statistic. You know, the old the second engine is there to carry you to the site of the accident. 
I’m not saying I would land at the closest strip no matter what, however, I don’t think I would continue to the destination like nothing happened. And if it’s anything like in helicopters, engine will often get shut down to prevent further damage or avoid risking damage. You wouldn’t do that in a single because it’s your only engine – so what if it gets totally trashed, you’ll worry about that later.
Twins are safer unless asymmetric at low speed/altitude. Fuel systems can also be more complex. That said I agree that they are unfortunately prevalent in accident statistics.
I think the main reason jets are safer statistically is not that the crews are better trained necessarily, but that a jet has more power and the fact that a V1 cut in a jet has much less asymmetry (as the engines are closer together). An engine failure at takeoff is much less of a deal in a jet than it is in a piston twin.
Does anybody know in what percentage of accidents (even roughly) did asymmetric thrust play role?
AdamFrisch wrote:
I think the main reason jets are safer statistically is not that the crews are better trained necessarily, but that a jet has more power and the fact that a V1 cut in a jet has much less asymmetry (as the engines are closer together). An engine failure at takeoff is much less of a deal in a jet than it is in a piston twin.
Have you tried OEI in your turbine Commander?
The reason jets are safer than MEP’s is simple, they are much easier to fly and they have much more performance avalable.
The skill level to handle an engine failure in a B737 is considerably lower in the seconds following the failure than an MEP, once the engine is secured the B737 becomes a bit more complicated but there are two people to sort out the subsequent actions.
The only big aircraft I have flown that required MEP standard of handling skills was the Lockheed L188 Electra with both engines on one side not operating, even when loosing a single outboard engine at a critical moment the thing was a pussycat……….. Oh and you just had to fly the aircraft while the non-flying pilot and Flight Engineer sorted the engine shutdown so it was a very low stress happening unlike the MEP pilot who has to sort the whole thing out himself.
I don’t think I know of a higher risk flying activity than being a low hours pilot flying an old under maintained MEP.
Does anybody know in what percentage of accidents (even roughly) did asymmetric thrust play role?
Good question, and it would need some digging. The OEI accident sub sets include: training Vmc demonstrations (hundreds in civilian training before the introduction of Vsse and more controlled demos); EFATO at below V2 (macho multi pilots pulling the ’plane off at Vx, having the bad luck to have an engine failure leading to a Vmc roll over on take off – some types have a low aerodynamic Vx relative to Vmc); failure to feather the engine resulting in failure to maintain height and in some cases loss of control; failure to feather the correct engine; failure to clear obstacles following an EFATO; engine fire leading to spar failure (without halon devices an engine fire in a multi gets to the wing spar in minutes; loss of control in IMC due to OEI; loss of control on OEI approach, usually following configuration changes; loss of control on an asymmetric go around; loss of control due to fuel imbalance; fuel management failure following engine failure; etc
Although my comment earlier was in tongue in cheek, being serious the skilll level to fly many twins is not that much higher than high performance singles. Since the discussion started surrounding the Aztec, in reality handling an engine failure on the Aztec is also pretty much a none event. Any idea of the aircraft dramatically rolling etc is just wrong. Yes, you do need to deal with the issues in the correct order and the blue line climb is not exactly scintillating but it all works pretty well. However there are twins that seriously lack any excess of performance so as ever it is horses for courses.
Fuji_Abound wrote:
Although my comment earlier was in tongue in cheek, being serious the skilll level to fly many twins is not that much higher than high performance singles.
If everything goes fine you are right. But taking a piston twin and having an unplanned engine failure on rotation (rather than a training one) they are far harder to deal with than in a jet. Of course, you have the option of flying in that scenario which you don’t have with a single but even in a very powerful King Air asymmetric flight is a handful single pilot compared with a jet.
In a Mustang if you lose an engine above V1, you fly the plane, clean up gear and flap, compensate for the asymmetry with rudder and climb at 1500fpm. That is it (you don’t even touch the engine controls until at an altitude where you have some time to go through engine failure checklists. Neil can maybe compare with a King Air.
