Hydraulics failed within seconds, but AAIB report leaves three key questions unanswered about Phuket-Delhi flight

The AAIB’s preliminary report explains how an Air India Airbus A320neo lost nearly 300 feet over the course of a major altitude upset. It does not explain why all three hydraulic systems failed within seconds of one another, or how they recovered just as quickly.

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Once all three hydraulic systems fail, effectively the aircraft is without power to the control surfaces.

The Phuket-to-Delhi flight was cruising at 36,000 feet on Aug. 4 when the failure triggered a stall warning and a sudden loss of altitude. At least 24 people were injured. The aircraft later resumed normal operations after the hydraulic systems recovered.

That sequence has left former pilots focused on questions they say the report does not answer. Capt. Sharath Panicker, a former Dreamliner pilot, said investigators needed to establish why the three systems went offline within four seconds. Once all three fail, he said, the aircraft is effectively left without power to its control surfaces.

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The questions which remain unanswered are what the real cause of the hydraulic system failure was and how the three systems failed in such fast succession.

A second pilot, who was not named, said Airbus does not train crews for a triple hydraulic failure because the scenario had not been contemplated. The pilot also questioned why the crew continued to Delhi rather than landing at Kolkata or Bhubaneswar, given the medical emergency, injuries and damage to the aircraft. The report says the crew assessed the cabin situation and chose to continue to Delhi instead of diverting to the nearest airport along the route.

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Why would you not go to Kolkata or Bhubaneswar when you have so much medical emergency and people are bleeding and the aircraft is in a damaged state?

A third pilot, also speaking anonymously, said the report raised more questions than it answered. The pilot said it did not establish the probable cause or contributing factors behind the violent loss and recovery of altitude, or the serious damage sustained. The report also did not include cockpit voice recorder data or explain the pilots’ side-stick inputs. Investigators have collected hydraulic components and fluid samples, along with fuel and oil samples and maintenance and operational records, for further analysis.

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The report raises more questions than it answers.