What I am suggesting, among other things, is that manual control could conceivably overpower, or at least foul, Boost. The boost was found in three degrees right wing down. That is where I believe it jammed whilst manual control by both pilots might have stalled the piston. Routing manual control inputs through even an unpowered hydraulic plumbing seems problematic.
Originally Posted by megan View Post
Design requirements are that in event of ANY sort of boost failure the system can be disengaged. The applicable rule says,OK, the boost unit, faulty or not, had no role to play as to accident causation, because the sole cause was a separated control cable, even though the CAB says "probable" cause.
The reason they say probable cause is because it fits their theory, even though there is no direct evidence of this specific failure... the pertinent equipment was never recovered. I have evidence that the boost unit was articulated at three degrees on impact, a position consistent with the aileron. Assuming one or both pilots were inputting left wing down, the boost did not answer. If unpowered, it wouldn't have mattered, and if powered, it would input left wing down as well. It did neither, during flight.
The report makes a deal about which yoke is “tensioned” at either boost quadrant location specific to each command cable. The yokes are connected, individual tension is not relevant. There was aileron input for left wing down, throughout. The report would have us believe this command did not reach the aileron, because one cable separated. That isn’t the reason. Even if one had separated, the connected yokes would deflect the left aileron upward. Some left roll would have been available, by design. The roll effect would be unusual, as both ailerons would be deflected up. If the right aileron was “stuck” at three degrees, in flight, (it was, the report says so,) the crew would have lessened the left roll input, and a balance would have been reached. An airplane can fly with one active aileron. It needed no study, either, the yokes would behave to control the roll, albeit in unorthodox fashion.
So. No evidence of separated (in flight) aileron cable, but an explanation of jammed Boost cylinder, as above.
But only probable.
Last edited by Concours77; 3rd Jan 2018 at 01:18.