In the cabin recording you hear how one pilot asks the other why “He cut off”obtaining in response a denial. However, the audio does not allow clearly to identify who pronounced each sentence. At that time, the co-pilot pilot the aircraft while the captain supervised.
During the brief flight, the switches They returned to their operational position, activating the system of Automatic realer. At the time of impact, an engine was generating thrust and the other, although restarted, had not yet recovered its power.
A flight of less than a minute
The aircraft remained less than 40 seconds in the air before falling into a densely populated area of Ahmedabadin western India. According to Flightradar24the plane amounted to 190 meters with good weather and disappeared from the radar to the 50 seconds.
The report, which has 15 pages And it was published this Saturday, it offers an initial panorama of the events. The investigation is headed by Indian authorities and has the collaboration of experts from Air India, Boeing, General Electricregulatory entities of India, USA and United Kingdom.
The system designed to prevent errors
Specialists claim that Fuel switches with lock lever They were designed to avoid accidental activations. These devices, dating from the 50s, must be Raised before being operatedand they possess Additional physical protections.
“It would be almost impossible to act both switches with one hand, and this makes an accidental deployment unlikely”, Explained a BBC A Canadian researcher requested anonymity.
This technical feature makes the case of Air India an atypical fact. If one of the pilots activated the switches – either by mistake or deliberately – new questions arise.
“Why … put the switches in the off position?”He said Shawn Pruchnickiexpert of the Ohio State University and former accident researcher.
“There are no records of an emergency. In critical situations it is common for incorrect buttons to be pressed, but in this case there were no confusion signs. There was no conversation that indicated that the switches were selected by error. This type of failure is rare without an obvious reason,” he told the BBC.
The role of voice recorder
Peter Goelzformer executive director of the NTSB of USAagreed: “The finding is very worrying: that a pilot has turned off the fuel switch a few seconds to fly”
He added that Voice recorder It should provide more information. “A simple comment like ‘Why did you cut the switches?’ It is not enough”
Goelz remarked that the audio suggests that someone He closed the valves of fuel and asked for a clear identification of voicesa complete and tagged transcription, and a thorough evaluation of all communications.
The Video recorder installation In cabin, as recommended by the NTSB, it could also have facilitated the determination of responsibilities, through a direct view of the actions of the pilots.
Other elements under analysis
The report indicates that both pilots like crew The medical controls passed and they were suitable. It also indicates that they were rested after arriving the day before Bombay.
A striking section of the report refers to a warning issued in December 2018 by the FAA about defective switches in the Boeing 737some of which did not have activated the locking function.
Although FAA did not issue a mandatory directive, it did recommend preventive reviews. As it was not mandatory, Air India did not implement inspections in aircraft with similar switches, such as Boeing 787-8 VT-ANB sinister.
Pruchnicki wondered if this could have had an incidence: “What happens when the blockade is deactivated? Can the engine be turned off just by moving the switch?”
Others, however, minimized the warning. “I never heard pilot complaints about this system. It is a point that must be investigated, but it could be secondary, ”said Goelz.
Kishore Chintaformer researcher of the AAIB of Indiahe suggested another hypothesis: “Is it possible that the electronic control unit has activated switches without human intervention?”If so, he remarked, it would be a serious failure.
The discounted hypotheses
The analysis also ruled out the possibility of fuel pollutionsince the samples taken were “satisfactory.” At the moment, they were not detected mechanical failures in it Boeing 787 nor in their Ge genx-1b engines.
The deployment of the Air Ram turbine (Rat) During the flight he evidenced a Total systemic failure. This emergency generator is activated when power is lost in both engines and allows the essential systems to be kept operational.
The landing train was also in a low position. A Boeing pilot explained that the complete retraction process usually ends at 120 meters of altitudethat is, in alone eight seconds.
“When the two engines fail, one is paralyzed. The only thing you think about is in the trajectory: where do I land?”, He explained.
Puchnicki considered that pilots tried to reactivate the enginesbut time was insufficient. “The left engine went out first and turned on again. The right took longer. Although both restarted, the thrust did not reach. It was too late”
Source: Ambito
