Engine Failure Scenarios

I performed a number of glide approaches to simulate an engine failure. I started from downwind abeam the threshold at 500ft agl. Then the same setup but 1000ft agl. Then overhead the airfield 2500agl. Finally I performed several simulated engine failure on takeoff scenarios.

Immediate Actions

As with any aircraft the first action is to lower the nose and trim to a suitable glide speed. I found that 60kts or 70kts were fine. Both result in a reasonably steep glide angle. Due to the loss of elevator authority below 55kts I kept a minimum speed of 60kts right into the flare.

Memory Items

These are pretty standard for any light aircraft:

Fuel - pump on, change tanks

Mixture - rich

Alternate air - on

Ignition - L, both, R, both.

Because I normally fly with the fuel selector in the both position, in this case I will select either L or R. After one minute if the engine has not started then I will select the opposite tank. This is to cover the situation of a fuel line vapor lock.

Glide

The Bearhawk glides steeper than most GA aircraft. With 3 or 4 people on board this is going to be quite steep.

Engine failure on takeoff

The main issue is to lower the nose immediately. This is even more important if taking off with F3 because of its added drag. Even with just one POB, the nose needs to be lowered very promptly, and well below the horizon initially to preserve airspeed.

The pitch feels quite different at this point because the trim is still set for takeoff and it's unlikely there'll be time to re-trim for landing. The Bearhawk lands fine even though trimmed for takeoff.

For reference, on my aircraft when the trim is set for takeoff, I gradually wind the trim wheel back through 160° for landing. Having an IO540 engine contributes to having a very forward empty CG (8.3"). Hence the large difference between trim setting for takeoff and landing. For Bearhawks with a more rearward empty CG, the trim setting for takeoff and landing is likely to be very similar (however the load capacity will be reduced).

Likely causes of an Engine Failure

A number of Bearhawks have suffered fuel related engine failures. These are thought to be caused by flying out of balance when only the Left or Right tank is selected, leading to unporting the fuel tank vents.

Alternatively, when flying in the BOTH position, if significantly out of balance, fuel can flow from one tank to the other, eventually running a tank dry.

During test flying I kept a minimum of 100 liters in tanks to protect against unporting. It was an easy way to mitigate the issue. Now I am much better at flying in balance and I routinely land with 40 liters in tanks.