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An indicative ATSB map as to how much larger gliding could make the search zone[/caption]
The ATSB is ready to accept the possibility that missing Malaysia Airlines flight MH370 was in a controlled glide in the final moments of its doomed flight almost two years into the southern Indian Ocean.
If that was the case, and all the other fundamental assumptions are correct, the current priority search area might have to be three times as large as it is.
This concession by the Australian managed search for the jet is made by the chief commissioner of the ATSB, Martin Dolan, in a paywalled interview in The Times.
The already extended priority sea floor search zone for the jet was based on the aircraft flying on a predetermined heading without further pilot input after first being deliberately diverted onto a west and then northwesterly course toward central Asia in the early morning of 8 March 2014 when it was en route to Beijing from Kuala Lumpur with 239 people on board.
If however there was control until very late in the flight, and it was glided even after the power to both engines stopped because of fuel exhaustion, it could have flown maybe 100 kilometres or more than modelled, vastly increasing the number of possible paths to an even larger area of the ocean than the 120,000 square kilometres that are being searched.
The Times report refers to the eventuality that Australia would publish a report explaining why the search had failed that would included recognition of the controlled end of flight scenario should nothing be found in the defined zone.
The search partners, Australia, Malaysia and China, have agreed that the current ATSB managed Malaysia instructed sea floor search will end on the exhaustion of this area pending no material discoveries of sunk wreckage or credible new leads.
That end of the ATSB search is generally estimated to come by the end of May, subject to the sea state generated by the weather, which will deteriorate as the southern winter draws nearer.
The ATSB search has in fact contemplated controlled flight scenarios in the past. It took about a year of lobbying by UK pilot Simon Hardy for his calculated end of flight scenarios, which involved ditching the jet while it had enough fuel left to deliver full control to a pilot, to be acknowledged.
Captain Hardy's optimal resting place for the wreckage was sonar scanned by the search late last year without result, although the calculations involved were accorded serious respect and consideration, and the margin for error is such that it might yet have come down within tens of kilometres of where he expected it could have ended.
Unpowered gliding is another matter. The risk of loss of control toward the end of such a descent to the sea surface is considered very high, and the satellite ping data, as described by the ATSB last year, suggested that after both engines failed, one some minutes after the other, the Boeing 777-200ER began to fall out of control toward an impact, and that the jet might even have been inverted before impact thus breaking the signal line of sight between a computer system antenna on the fuselage and an Inmarsat communications satellite parked in a geosynchronous location over the west Indian Ocean.
If as The Times report says, the area in which MH370 might have come down is about three times larger than the priority search zone, then there would only be a one in three chance that the jet lies within it, rather than somewhere surrounding it.
Which raises an interesting speculation as to what China might do, once the Australian search ends. It might continue the search rather than go home. Most of the victims of the loss of MH370 were China nationals, and the derision with which Beijing held the conduct of the Malaysian authorities early in the saga is on the public record.
By coincidence or otherwise, The Times story came out at the same time as an unusually early release of the JACC/ATSB Wednesday search update.
This is what the very brief update
says about the Chinese ship
and its sharp synthetic aperture ultra deep water scanning sonar towfish.
Dong Hai Jiu 101 has departed Fremantle to transit to the calibration range where the towfish will be trialed. It will then return to Fremantle to land personnel embarked only for the trials, before departing around 18 February for the first of three swings in the search area.