Investigators have exposed a cool discovery in the initial investigation in the Air India Flight 171 accident in which 260 people were killed in June.
A few seconds after takeoff, both 12-year-old Boeing 787 Dreamliner’s fuel-control switch suddenly went into a “cut-off” position, hungry fuel engines and triggered the total power loss. Switching on the “cut-off” is usually done only after landing.
Cockpit voice recording catches a pilot, asking the other why he did the “cut-off”, to which the person responds to that he did not. The recording does not clarify who said what. At the time of takeoff, the co-pilot aircraft was flying, while monitoring the captain.
The switch was returned to their normal infly position, triggering the automatic engine relay. At the time of the accident, one engine was re -acquired, while the other was relieved, but the electricity was not yet recovered.
Air India Flight 171 Western Indian city of Ahmedabad was airborne for less than 40 seconds before crashing in a crowded neighborhood, marking one of India’s most stunning aviation disasters.
Investigators are investigating the debris and the cockpit recorder of what went wrong after the takeoff. According to Air India flight Flightradar24, the location climbed 625 feet in a clear season before losing data in 50 seconds. Saturday’s 15-pest report provides initial insight.
The US National Transportation Safety Board and the UK participants also raise many questions under the leadership of Indian officials from Boeing, GE, Air India and Indian regulators.
Investigators say the liver -lock fuel switch is designed to prevent contingency activation – they should be drawn to unlock before flipping, a safety feature back dating back in the 1950s. Built for accurate standards, they are highly reliable. The protective guard brackets carried them forward with casual bumps.
The investigator of the Canadian -based air accident, who wanted to remain anonymous, would be almost impossible to draw both switches with the same movement of one hand with the same movement of one hand, and it is unlikely to be accidental deployment. “
This is the reason that the case of Air India stands.
“This question begs: Pilot, any pilot, really pushed the switch into a closed position,” said Sean Pruchi said, “This question begs,” said Sean Puchiyi, a former airline at Ohio State University.
“Was this intentional, or confusion a result? It is unlikely, because the pilots did not say anything unusual. In many cockpit emergency situations, the pilots can press the wrong button or make the wrong choice – but there was no sign of such a situation here, nor is there any discussion suggesting that the fuel switch was mistakenly chosen.
Getty imagesPeter Goelz, a former managing director of the US NTSB, echoed a similar sentiment: “The search is very disturbing – that a pilot has closed the fuel switch within a few seconds of the flight.”
He said, “The cockpit is much more likely than the voice recorder.
“New details show that someone in the cockpit has closed those valves. The question is, who, and why? Both switches were closed and then resumed within seconds. The voice recorder will reveal more: Will Flying Pilot was trying to resume the engines, or monitoring a?”
Investigators believe that the cockpit voice recorder – pilot mixes, radio calls and surroundings with audio from cockpit sounds – is the key to this puzzle.
“They haven’t yet identified the sounds, which is important. Generally, when the voice recorder is reviewed, people familiar with the pilots are present to help the match voices. So far, we still do not know which pilot switched the switch and turned back,” said Mr. Goelz.
In short, investigators say what is needed is clear voice identity, a full cockpit transcript with label speakers, and intensive review of all communications from the moment the aircraft was pushed back from the gate to the time when it crashed.
They also say that it outlines the need for a cockpit video recorder recommended by NTSB. An over-the-shielder scene will show whose hand was on the cut-off switch.
Prior to boarding flight 171, both pilots and crew passed the breathing tests and fit to fly, stating in the report. The pilot in Mumbai reached Ahmedabad a day before the flight and got enough rest.
But the investigators are also zero that what they describe is an interesting point in the report.
It says that in December 2018, the US Federal Aviation Administration released a special airworthiness information bulletin (SAIB), stating that some Boeing 737 fuel control switch was installed with switch locking facility.
While the issue was noted, it was not understood an unprotected situation that required an airworthiness directive (AD) – a product legally applied to correct the unprotected position in a product.
The same switch design is used in Boeing 787-8 aircraft, including Air India’s VT-NB which crashed. As Saib Advisor was, Air India did not conduct a recommended inspection.
Bloomberg through Getty ImageMr. Puchiki said that he is wondering if there was any problem with fuel control switch.
“What does it do [bit in the report] Absolutely mean? Does this mean that with a single flip, it can turn off the switch engine and cut fuel supply? When the locking feature is decomposed, what exactly happens? Can the switch just shut down itself and turn the engine shut down? If so, it is actually a serious issue. If not, it should also be explained, “he said.
Other, however, it is not confident that this is an important issue.
“I have not heard about it that seems to release a low-profile FAA. Nor I have heard any complaint [about the fuel switches] From pilots – which are usually quick to speak. This is worth the investigation since the mention, but it can only be a distraction, “said Mr. Goelz.
Captain Kishore Chinta, a former explorer of the Aircraft Accident Investigation Bureau of India, wonder whether the switch is stuck due to the aircraft’s problem with the electronic control unit.
“Can the fuel cut-off switch be triggered electronically by the electronic control unit of the aircraft without movement by the pilot? If the fuel cut-off switch got electronically stuck, it is a cause of concern,” he told the BBC.
The report states that fuel samples from fueling tanks were “satisfactory”. Experts suggested fuel contamination as a possible cause of the first double engine failure. In particular, no advice is given for Boeing 787 or its GE GenX -1B engine, now further investigation is pending with mechanical failure.
It also stated that the aircraft’s Ram Air Turbine (RAT) was deployed – a clear indication of a major system failure – and the landing gear was found or not withdrawn in the “Down position”.
The rat, a small propeller who spreads from the bottom of the Boeing 787 Dreamliner, acts as an emergency backup generator. It automatically deploys in flight when both engines lose power or if all three hydraulic systems register severely low pressure, supplies limited power to keep the required flight systems running.
“The deployment of Ram Air Turbine (RAT) supports the conclusion that both engines had failed,” said Mr. Puchiki.
Boeing 787 pilot explained why he felt that the landing gear had not been withdrawn.
“These days, every time I fly in 787, I look closely at the landing gear retraction process. As long as the gear handle is drawn, we are already at 200 feet (60.9 meters), and the entire gear retraction process is completed to about 400 feet – a total of eight seconds for the aircraft’s high -stagnation of the aircraft.”
Pilot believes that a flight did not have time to think.
“When both engines fail and the aircraft starts going down, the response only becomes beyond the shock – you become numb. At that moment, the landing gear is not your focus. Your brain is on one thing: Flight path. I can safely put this aircraft down? And in this case, just did not have enough height to work.”
Investigators say the crew tried to recover, but it happened very fast.
“The engine was shut down and then turned back. The pilots realized that the engine was losing loud – probably the first one is likely to resume a left, followed by the right,” Mr. Puchiki said.
“But the correct engine did not have enough time to splose back, and the emphasis was inadequate. Both were eventually set to” run “, but the left stopped with the left first and was too late to recover, it was too low, it was too late.”
