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Old 12th Oct 2016, 01:49
  #98 (permalink)  
Join Date: Dec 2013
Location: Norfolk
Age: 62
Posts: 1
One thing that occurs to me while watching your videos is that the ailerons are functional throughout the simulation run. You can vary the aileron inputs to attempt to duplicate the actual flight path taken by the original accident aircraft, but does that actually represent the true aileron positions during the accident flight?

Once the aileron drive cable broke, the ailerons may have been held in a fixed position for a time by powered assistance until the pressure bled away or the power boost was turned off. Alternatively, the ailerons may have moved due to airflow over the wing and prop wash from the engines.

Because of this, it is difficult to conclude that the turning circle was continuous or at a constantly and steadily increasing bank angle. Clearly the aircraft banked to the right after take off and that bank increased to a point where the aircraft could no longer remain in the air. There is the possibility that the bank angle increased in a series of 'jumps' as the crew struggled to regain control and as the aileron deflection altered due to crew inputs such as turning off powered assistance and changing airflow patterns over the wing.

Rather than assuming a steadily and smoothly incresing bank angle, you might want to try increasing the bank in a series of steps that might correspond to attempts to regain directional control.

The initial cable break would require a left rudder deflection to try and correct the bank. The ailerons would progressively become more susceptible to aerodynamic forces, and propwash effects as engine power levels were adjusted and the bank angle increased.

It seems clear from your tests so far that this wasn't a nice neat curving climb and descent with a steadily increasing bank. You have already concluded that this simply wasn't possible if the aircraft was to finish up at the actual crash site.

Perhaps a take off with a gentle 5 bank which then increases steadily to perhaps 30 bank at the highest point in the flight, followed by a jump to 45 increasing to 60 over perhaps 5-10 seconds, then a further roll to 70+ degrees to the impact point. I feel this would more accurately reflect the possible flight profile and allow the turning radius to agree with the results recorded in the accident investigation as to impact point in relation to the runway and airfield.

The problem is that once the aileron cable broke, it is very difficult to establish the position of the ailerons between that point and the moment of impact, when witness marks would reveal the deflections with reference to the wings. Did the ailerons remain in one fixed position, did they flutter in the slipstream, were they influenced by the engine power settings, or did they move in response to control power boost devices being cycled off and on, perhaps repeatedly?

Considering the flight as a series of step changes which temporarily mitigated the situation, but then failed is probably the way to go in understanding this accident.
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