From the final position of the a/craft.
The wingbox is intact, the main spar is intact from outboard #2 to outboard #3.
The tail section appears to have remained partially attached.
The V/S is intact save for crumpling at its peak. The HS are intact.
And the structure is upside down. I don’t see any ruts consistent with “slide”.
There is a long rut at a bias of about sixty degrees to the structure, but it is continuous on both sides, and appears to be man made.
There is wing structure visible outboard of both MLG, and upper cowling of #3 is present next to the wheels of Starboard landing gear.
“Sliding” would appear to be not supported by the photographic evidence IMO. The tail cone would be corrupted extensively, and the orientation of wing box/tail would similarly have been less suggestive of structural continuity.
What I see would suggest that this wreckage had been airborne just prior to impact at this location. In other words, it flopped onto the ground, it did not slide.
As to CAB, I think it is a reach to have concluded the cause of this accident within hours of its occurrence. Their text on page four suggests that a turn was initiated while the aircraft was still on the ground. It also suggests a climbing turn. For that to have occurred as they describe, the maximum altitude attained would have had to have been at least twice that of what ATC testified to.
Also, from page four, it states five witnesses report a change in “engine noise” as the turn was initiated.
There would be NO reason to change thrust this early in take off, unless there was something else going on. “Noise abatement”? Doubt it.
The Electra has thrust levers, not throttles. Engines maintain approx. 13000 rpm. What they heard is likely a change in propellor pitch. Most turboprops make far more noise with the propellors than engines.
Five witnesses? Remarkable. If the aircraft was on runway heading when the turn initiated, and altitude was as low as reported, Why the concurrent noise change? A change in heading absent aileron means a thrust problem. Gearbox? Pitch pressure? The aircraft would be at takeoff power, so a change in noise might indicate engine trouble. Not even addressed by CAB.
My first inclination having this data would not be aileron malfunction. Loss of thrust on the right side? In any case, without discussion, CAB concluded the cause virtually immediately. Right side aileron was determined to be in three degree up, (wing down) post crash. Three degrees is one third of aileron deflection available without boost, in manual. Maximum aileron in boost mode is over thirty degrees.
Pretty weak in roll command. At first blush, not nearly enough to have caused this accident...
Last edited by Concours77; 22nd Dec 2017 at 00:10.