Investigators probing the crash of an AirAsia jetliner are analyzing preservation statistics of a key a part of its computerized manage structures, and the way the pilots may have handled the plane if it failed, two humans familiar with the problem stated.
An outage of the twin Flight Augmentation computer systems (FAC) could not have at once triggered the Dec. 28 crash, experts say, but without them the pilots would have needed to depend upon manual flying abilties which can be frequently stretched at some stage in a sudden airborne emergency.
“There appears to be a few issue with the FAC,” a person familiar with the research stated, adding that greater records become being sought from the manufacturer and airline.
Indonesia has said the Airbus A320 jet climbed abruptly from its cruising top and then stalled, or lost raise, before plunging out of manage into the Java Sea, killing all 162 human beings on board.
A second person familiar with the probe said investigators have been searching at how the pilots treated the chain of activities main up to the crash. Neither man or woman agreed to be diagnosed, due to the fact details of the research remain exclusive.
The pair of computer systems comprising the A320’s FAC machine is in particular chargeable for controlling rudder moves and helping to keep the airplane strong, as nicely detecting wind shear, or unexpected adjustments in wind speed or path.
Indonesian mag pace suggested a sequence of renovation troubles with the automated rudder machine of that precise plane within the days and months before the lack of Flight QZ8501.
images of wreckage retrieved from the Java Sea offer little proof that the crash become because of troubles with the rudder.
but, after partly analyzing information from the “black box” voice and flight records recorders, investigators have extended their interest to the FAC computer systems, the two human beings familiar with the probe said.
A hassle with the system may assist give an explanation for every other key element of the crash – why the jet did no longer routinely accurate itself earlier than moving into a stall, even if accidentally endorsed to achieve this by team.
Airbus jets are designed to offer “flight envelope protection,” making it simply not possible to push them outdoor secure layout limits while running in regular flying mode.
but while the computer systems are unable to carry out their tasks, manage is robotically surpassed to the pilots who have to fall again on training and fly manually, in so-known as “exchange” mode.
A failure of both FAC computers – one number one, the alternative again-up – is one of these rare circumstances that could reason the usual stall protection to journey.
That on my own might not provide an explanation for why such a jet might crash and it is not likely to be the only state of affairs being considered by means of investigators.
It turned into no longer clear when any fault might have developed, however it would, if showed, be one possible explanation of the way the plane got into the country wherein the Indonesian pilot and French first officer would need to take over and display skill underneath stress.
“Stall safety can ride in very remarkable instances and the pilots need to react to that,” an A320 pilot said, asking not to be named on account that he isn't allowed to talk to media.
Airbus said it'd not touch upon the research or the crashed jet, however harassed that this form of aircraft is designed to be flown manually even when the protection buffer isn't always available.
“The aircraft remains completely controllable in case you lose the two FACs,” an Airbus spokesman said via e mail.
“The result of losing the 2 FACs is that the pilot has to fly manually like a conventional aircraft, which via definition has no flight envelope protection.”
initial file Due
Indonesia’s country wide Transportation safety Committee (NTSC) declined to remark. The enterprise will submit its preliminary file to the international Civil Aviation employer later this week, but stated on Tuesday it would now not include an evaluation of the statistics from the black containers.
AirAsia, relating to the jet through its five-letter registration, said it could not touch upon the plane or the investigation.
“we are unable to touch upon technical topics associated with PK-AXC at the moment as we would like to keep away from adding to hypothesis while the investigation by way of the NTSC is still ongoing,” an AirAsia spokeswoman stated by means of electronic mail.
In October, airlines had been given 4 years to improve FACs on A320 jets at the subsequent repair after a design evaluate. An emergency european protection directive in December instructed group the way to disable computerized flight protections themselves but handiest in extraordinarily uncommon situations.
there's no indication Airbus or regulators have recognized anything that would raise wider issues about the protection of the 6,a hundred A320-own family plane in operation.
below aviation regulations, Airbus must notify operators international if it discovers something that might have an effect on the protection of the entire fleet and it has now not so far done so.
however investigators will want to observe what caused the aircraft to slip out of its standard effectively cocooned flying mode, the way it entered a stall and what actions the crew took in reaction.
a few pilot unions, consisting of those at Air France after an A330 jet crashed inside the Atlantic in 2009, have argued within the past that Airbus structures are so complicated that pilots may be beaten when things pass wrong. The jet maker denies this.