Researchers revealed a cool discovery in a preliminary study on the Air India Flight 171 disaster, which in June. 260 people were killed.
Just seconds after the rise, both twelve years of Boeing 787 Dreamliner fuel control switches suddenly switched to the “marginal” position, starving fuel engines and causing a total power loss. The transition to “cut” is a step, usually done only after landing.
The hanging voice record captures a single pilot asking why he “did the boundary” to which the person responds that he did not. The entry does not explain who said. During the carpet, the Co-Pilot flew with an aircraft while the captain watched.
The switches were returned to the normal detection position, causing an automatic motor support. During the accident, one engine regained attraction and the other – Relit, but has not yet recovered power.
The Air India Flight 171 was less than 40 seconds, having previously crashed into a crowded neighborhood in West Indian city in Ahmedabad, marking one of the most alarming Indian aviation catastrophes.
Researchers are investigating debris and cab recording facilities to understand what happened immediately after the ascent. The Air India flight rose to 625 feet, in clear weather, before losing local data for 50 seconds, through the Frightradar24. Saturday’s 15 -page report provides early insights.
A study led by Indian authorities, together with the US National Transport Safety Board and UK participants, along with Boeing, GEIN, Air India and Indian regulators, experts also raise many questions.
Researchers say Lever -lock fuel switches are designed to prevent random activation – they must be pulled into unlocking before inverting, and safety function dated in the 1960s. Made to strict standards, they are very reliable. Protective protection holders continue to protect them from random bumps.
“It would be almost impossible to pull both switches with a single hand movement, and it makes accidental deployment unlikely,” the Canadian Air accident investigator who wanted to remain an unnamed canada told the BBC.
That is why the Air India case stands out.
“The question is: why the pilot, any pilot, actually pushes the switches into the off position,” said Shawn Pruchnicki, a former airline accident investigator and aviation expert at Ohio State University.
“Was it thoughtful or because of confusion? It seems unlikely because the pilots have not reported anything unusual. In many cabin emergencies, pilots can press the wrong buttons or make the wrong choices –
Air India Flight 171 crashed in a congested neighborhood of Ahmedabad [Getty Images]
Peter Goelz, former US NTSB Director General, repeated a similar approach: “The results are very worrying – that the pilot turned off the fuel switch in seconds after flying.”
“It is likely that the cabin recording device is likely to have much more than what was shared. One note like” why you cut switches, “he said.
“The new information shows that someone in the cab closes those valves. The question is who and why both switches have been turned off and then re -launched in seconds. The voice recording device will reveal more: did the flying pilot try to restart the engines, or watch?”
Researchers believe that the cabin recording device – with the audio audio of the test microphone, radio and environmental cab – is considered the key to this puzzle.
“They have not yet set voices that are very important. Usually, when the voice recording device is reviewed, there are people familiar with pilots to help reconcile voices. At the moment we still do not know which pilot has turned off the switches and turned on again,” he said. Goelz.
In short, the researchers say that what is needed is a clear voice identification, a full transcript of the cab with the marked speakers and a detailed review of all connections from the moment the plane was rejected from the gate to time when it crashed.
They also say this emphasizes the need for Cockpit video recording devices as recommended by NTSB. The image over the shoulder would show which the hand was on the marginal switch.
Before boarding the 171 flight, both pilots and crew maintained respiratory tests and were cleaned, the report said. The pilots in Mumbai came to Ahmedabad the day before the flight and had a proper rest.
However, researchers also do not go into what they describe are interesting in the report.
It is said that 2018 December The US Federal Aviation Administration has published a special fitness ballot for suitability (SAB), stressing that some Boeing 737 fuel control switches were installed with a locking function.
Although this issue has been marked, it was not considered an insecure condition that requires the right of the Aircraft Directive (AD), a legally implemented regulation to correct the unsafe conditions of the product.
The same switches are used in the Boeing 787-8 aircraft, including the Air India VT-AB, which crashed. Since SAB was advised, Air India did not carry out recommended inspections.
Boeing 787 Dreamliner Airplane Cab, which Air India owns at Air Exhibition in India [Bloomberg via Getty Images]
Mr Pruchnicki said he was wondering if there were problems with fuel control switches.
“What it does [bit in the report] Mean exactly? Does this mean that with one inverter, that switch can turn off the engine and reduce fuel supply? What exactly happens when a locking function is disconnected? Can the switch just distance yourself from off and turn off the engine? If this is the case, it’s a really serious problem. If not, it also needs to be explained, ”he said.
However, others are not convinced that this is the main problem.
“I haven’t heard of what seems to be a low profile faa release. I have not heard any complaints [about the fuel switches] of pilots who usually speak quickly. It is worth examining because it is mentioned, but it may be just distraction, ”Goelz said.
Captain Kishore Chinta, a former investigator of the Indian Aircraft Investigation Bureau (AAIB), wonders whether the switches are mistaken for the problems of an aircraft electronic control unit.
“Can fuel cut switches can be electronically activated by a plane electronic control unit without pilot movement? If fuel reduction switches stumble electronically, it is a concern,” he said.
The report states that fuel supplementation tanks were “satisfactory”. In the past, experts offered to contaminate fuel as a possible cause of double motor failure. It is noteworthy that no tips for the Boeing 787 or its Genx-1B engines have been announced by any mechanical failure for the time being, until further investigation is expected.
It is also stated that the Ram Air Turbine aircraft was deployed – a clear sign of the main system failure – and the descent equipment was found in a “down position” or did not retreat.
A rat, a small screw continuing from the bottom of the Boeing 787 Dreamliner, acts as an emergency spare generator. It automatically deploy during flight when both engines lose energy, or if all three hydraulic systems record critically low pressure, both for limited energy to maintain essential flight systems.
“The deployment of RAM air turbines (rats) greatly confirms the conclusion that both engines have broken,” he said. Pruchnicki.
The Boeing 787 pilot explained why he thought the landing equipment had not retreated.
“These days, every time you get to 787, I notice a careful divert gear interruption process. By the time the gear handle is pulled out, we are about 200 feet (60.9 m), and the entire gear breakage completes about 400 feet – about eight seconds in total, thanks to the aircraft high pressure hydraulic system.
The pilot believes that that flying did not have time to think.
“When both engines collapse and the aircraft starts down, the reaction goes beyond only astonishment – you go down numb. At that moment, landing equipment is not your attention. Your mind is one thing: flight path. Where can I safely drop this aircraft?
Researchers say the crew tried to recover, but it happened too quickly.
“The engines were turned off and then turned on again. The pilots realized that the engines were losing traction – most likely re -launched the left first and then the right,” Mr. Pruchnicki.
“However, the right engine was not enough time to turn backs up, and the traction was not enough. Both were decided to” run “, but on the left first closed and the right to recover too late, it was just too little, too late.”