The stall characteristics of the Belfast weren't good. The RAF solution was to operate with the stall warning settings well above the actual stalling speed.
In about 1973 a Belfast flying from Cyprus to Brize Norton suffered a failure of the tail de-icing system and the ice build up caused the aircraft to fly tail heavy. At one point they got below the the nominal stalling speed but with no stall warning. I was involved in the programme to reset the stall warning margins on the Belfast fleet. This was a very stomach churning experience - we flew with test equipment wired into the electrical 'cupboard' at the rear right side of the flight compartment and the aircraft could lose up to 5,000 feet in the recovery from a 'clean' stall. After our measurements, adjustments were made to the stall warning vane settings; the resulting stall warning margins were tested and found to give ample warning that the airspeed was getting precarously low, while still being safely above the actual stalling point for the various flap configurations. That solution ought to have sufficed for civil operations.
After a deep stall accident to a BAC1-11 the UKCAA seem to require a stick pusher on just about anything that has a pilot. Its a fact of aerodynamics that anything that can fly can and will stall if the pilot insists on ignoring the signs and/or warnings. I do know of an RAF VC10 incident where the Stall Ident System (i.e. Stick Pusher) activated without warning while close to the ground and the pilot, taken by surprise, almost lost his grip on the control wheel. Now that could have been just as nasty as a deep stall - I believe that Boeing's designers have it right - an accurate and reliable stall warning system is all that is needed.
Last edited by Blacksheep; 31st Jul 2007 at 01:33.