Pilots Notes continued

What speed do you glide at give you the best chance of pulling off a successful forced landing?

The best gliding speed is usually around 60 kts in a light aircraft and this speed will give you the maximum distance the aircraft will travel before reaching the ground. However, this will be in still air conditions and any wind may have a significant effect on the ground distance you can travel.

So what will be the effect of putting the speed up by say 10 kts? The diagram below shows that for maximum distance we want to glide at the speed giving the best Lift/Drag ratio and this speed is where a tangent drawn from the origin meets the drag curve.

Increasing the speed slightly over the best gliding speed hardly effects the distance you travel but gives you a bit more energy to play with in the critical final stage of the approach. Flying even a small amount below the best glide speed will however reduce the gliding range particularly into a head wind and could lead to a stall spin in the final stage of the forced landing.

The key thing now is to keep your speed 5 to 10 knots above your best gliding speed so as not to turn the engine failure into a stall/spin accident, you will probably survive an arrival with the wings level and the fuselage parallel with the ground but going in pointed end first is usually not survivable.

The wind.

The wind speed will probably be a significant fraction of your landing speed so if possible always land with a headwind, however slight. Only in the most dire of circumstances try to land downwind.

So the basic rules for facilitating a successful forced landing following an engine failure are:-

1.††† Speed slightly above the best gliding speed, up to 10 kts.

2.††† Don't Stall, Donít Stall, Donít Stall

3.††† Arrive at the ground with wings level and the fuselage parallel to the ground

4.††† Don't land downwind.

"It is better to go into the far fence at taxiing speed than the approach end fence at flying speed."