A key assumption about how MH370 behaved in its last moments isn't necessarily supported by the fine print in a Boeing manual

A previously overlooked line in a Boeing 777 training manual suggest that the Malaysia Airlines flight MH370 could have experienced an additional roll to the left as it plunged at very high speed to its impact in the south Indian Ocean after the jet ran out of fuel before crashing on March 8, 2014.

In his latest paper, MH 370 investigator Victor Iannello analyses an end-of flight scenario with banked descent and no pilot input.

He draws attention to this note found by fellow independent MH370 investigator Don Thompson in the Aircraft Maintenance Manual (AMM) for the B777, in the section on the Ram Air Turbine System:

Training Information Point

When the RAT is extended and hydraulics off, the airplane rolls left. Two to three units of right control wheel rotation are necessary to hold the wings level.

As explained in the analysis, the Ram Air Turbine or RAT is a very small tethered windmill type electrical generator hard wired to pop out into the slipstream of an airliner and provide some critical instrumentation and systems functioning in a jet that is no longer drawing power from engine driven generators.

Victor Iannello’s paper reads as an important refinement of the general scenario and conclusions drawn by Boeing’s end-of-flight simulations for MH370 with the assumption that there was no pilot input. Those simulation results were released in November 2016 by the ATSB as part of a report entitled MH370 – Search and Debris Examination Update.

This isn’t about suddenly identifying the final resting place of large, or maybe, not so large, chunks of the heavy wreckage of MH370, a Boeing 777-200ER, which was carrying 239 people on a red eye flight from Kuala Lumpur to Beijing when it vanished on March 8, 2014.

It’s about collecting and analysising data and working through the possible implications that arise in such studies. As such its the antithesis of the rush-to-judgment, mind-made-up coverage that has dogged the MH370 story since shortly after the jet disappeared.

The analysis includes a video showing the view from the cockpit during the simulated descent. The aircraft rolls past 180° and impacts the water at a pitch angle that is almost vertical. During the descent, the speed reaches about Mach 1.1, breaking the sound barrier, and the descent rate approaches 60,000 feet per minute.

(Although not discussed in this paper, the recovered debris from MH370 supports the high likelihood of airframe disintegration during a descent that would have exceeded some design limitations and a high energy impact with the sea surface by the denser and stronger parts of the jet.)

The sea floor search for MH370 was called off by Australia and Malaysia with the apparent agreement of China in January. The Australian Prime Minister, Malcolm Turnbull, has in the last week dropped hints that a physical search might resume.

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