AF447

[Will Fraser]

I certainly appreciate the focus on data, especially as it relates to Box/Pilot interface. My understanding of ACARS suggests to me a system that is designed not specifically to do what most folks here would like to see it do. It is not a streaming super computer. Its computing and tx formats are designed for a non-critical logging and storage of mx demands to be addressed later, at arrival.

Given the grand exposure to very limited evidence, the number and span if hypotheses is narrow. ACARS, pieces of debris, and an interesting record of possible precedent failures. Other than a short term at medical school, I am wholly unprepared and incompetent to consider the humanity as evidence.

A precedent record of pitot issues is a start, and what remains of the air data might be foundation for considering a high altitude high speed upset occurring at or near a/p disconnect. The parameters for reversion to hand control seem rather wide at M.80, (see PJ2 description of AltLaw), even with healthy pitots, the amount of control available to a surprised Command Pilot seems large. It is apparent with the evidence that at a/p disconnect, the roll control was a range of 60 degrees, albeit applied at a rate that wouldn't disagree with a/p limits, (load). This rate and range is what presents to me a potential for a very quick disconnect by an a/p that might have been doing a grand job, conveying no issues to the crew, but at a/s cue loss could be an enormous challenge to format change, autos to hand. Any roll or turbulence induced yaw or pitch excursions, without cues in a dark and flickering cockpit suddenly requiring hand control inputs may have begun a rapid upset. The VS was found virtually unblemished. The Rudder has a severe tear at its proximal swing with the aft fuselage, but remained fully and consistently attached to its mate.

A loss of the VS and Rudder as a result of the initial upset, some combination of yaw, pitch, and roll either coordinated or not may have begun the out of control descent. As the a/c would have been decelerating from its max. speed after upset, the remaining airframe would have been giving up its structure (in some unknown sequence) and created a cone of ballistic dependent debris on the Ocean's surface below. Deployed or not, the spoiler panel shows severe damage that suggests to me extreme aerodynamic loading, flutter and separation. The suggestion from its appearance is that similar loads occurred elsewhere on the a/c, enhancing the theory of an aerodynamically destructive descent. The debris collected is light and flat, with high area to mass ratio. It travelled more slowly through the air than heavier material, and most likely further.

Without a functional tail, the only other over water accident I am familiar with had the fuselage and wing structures descend immediately into the water in virtually a vertical and inverted entry, an MD-80.

I appreciate the technical nature of this thread. It is an extremely informative and enlightening enterprise.

Will Fraser