Damage analysis of two flight-control surfaces from the missing Malaysia Airlines flight MH370 indicate that the Boeing 777-200ER’s flaps were retracted at the point when the aircraft broke up.
The analysis by the Australian Transport Safety Bureau – while not fully conclusive – would indicate that the jet was not conducting a controlled descent.
Examination of damage to the outboard flap as well as the flaperon from the starboard wing shows the flap was “most likely” in the retracted position, it states, while the flaperon was probably in its neutral position – a configuration consistent with cruise flight rather than approach.
“The possibility of the damage originating from a more complex failure sequence, commencing with the flaps extended, was considered much less likely,” says the inquiry.
Over 20 pieces of debris have attracted the interest of the inquiry into the disappearance of MH370 in March 2014, mainly retrieved from the coastlines of eastern Africa, Madagascar, Reunion and Mauritius.
The latest configuration analysis has focused on the flaperon and an inboard section of the starboard outboard flap, to determine whether these control surfaces had interacted with their support structures and actuation mechanisms during the break-up – potentially revealing the surfaces’ position status at the time.
Determining the configuration could assist with modelling the 777’s descent profile and refining the search zone for the aircraft.
The analysis looked particularly at impact damage to aluminium stiffeners, which it attributes to a deflection-control support track – a component fixed to the aft of the wing which helps guide the flap as it is deployed.
This damage is “significant”, says the inquiry, because the support track would have to have been fully inserted into the flap, in the retracted position, to lie adjacent to the damaged stiffeners.
Investigators also noted that both the flap and the flaperon sustained similar damage in the vicinity of their rear spar rivet lines, and that these areas are aligned only when the flap is retracted.
“With the flap in the retracted position, alignment of the flap and flaperon rear spar lines, along with the close proximity of the two parts, indicated a probable relationship between two areas of damage around the rear spars of the parts,” says the inquiry analysis.
“This was consistent with contact between the two parts during the aircraft break-up sequence, indicating that the flaperon was probably aligned with the flap, at or close to the neutral position.”