Originally Posted by
safetypee
dixi, AFAIR the Trident accident was during a pre-delivery production test flight, thus additional experimental test-flight devices were not fitted.
Nowadays where pre-delivery testing requires a stall check either with or without stick push (stall ident) enabled, an additional glare-shield stall panel is fitted showing AoA calibrated for stick shake / push. Preflight the AoA vanes and indicator are crosschecked, so that if when inflight the shake / push do not occur at the expected AOA then the test is stopped.
The BAe 146 used such a panel, which may also have been approved for training stalls, providing the shake / push was enabled and checked / calibrated pre-flight.
Mmmm... Twice, in another life I have terminated stall tests during a certification validation when the stall ident/stick pusher didn't operate at the scheduled speed. As a flight test team, our flight test engineer concentrated almost exclusively on the ASI during the deceleration. We allowed 1kt below the scheduled speed - if it were possible to read the ASI to that accuracy, before terminating the flight. Very stressful knowing that the pusher is required because of deep stall concerns, and no stall test instrumentation fitted.
These tests can be very demanding to fly. For the stall devices to operate on schedule, the correct approach must be flown. Any errors in approach rate or small G errors will negate the approach.
The TP often has little familiarity with the type and the manufacturer takes a dim view of the termination of flights - no pressure.