Air India Phuket-Delhi Flight Probe: 11 System Alerts, Three Hydraulic Warnings Before Autopilot Disconnection

The investigation into the August 4 Air India Phuket-Delhi flight incident has taken a new technical turn, with a post-flight maintenance report recording 11 system alerts within two to three minutes, including three hydraulic low-pressure warnings followed by an autopilot disconnection, sources familiar with the probe said.

The aircraft, an Airbus A320 bearing registration VT-EXO, was operating Air India flight AI2379 when it experienced a sudden altitude variation of around 300 feet during cruise amid turbulence.

Three Hydraulic Warnings Recorded Within A Minute

According to the maintenance report, the aircraft registered three hydraulic low-pressure warnings involving its green, yellow and blue hydraulic systems within roughly a minute.

The autopilot was recorded as disengaging shortly after the hydraulic alerts.

Investigators are now examining whether the hydraulic warnings were linked to the autopilot disconnection and the subsequent altitude variation experienced by the aircraft.

The report also recorded alerts involving the aircraft’s emergency exit doors and other systems during the same period.

Autopilot Disconnected Again Before Landing

The maintenance record contains another autopilot-off entry at 5:22 GMT, before the aircraft landed in Delhi.

According to sources, this suggests the autopilot was restored or re-engaged after its initial disconnection and was switched off again later in the flight.

Despite the alerts, the aircraft remained airborne for nearly one hour and 20 minutes after the initial hydraulic warnings before landing safely in Delhi.

The maintenance report has been shared with the Directorate General of Civil Aviation (DGCA) and the Aircraft Accident Investigation Bureau (AAIB).

300-Feet Altitude Variation Left 24 Injured

Air India flight AI2379 was carrying 137 passengers, including three infants, and eight crew members when it encountered turbulence on August 4.

The aircraft experienced a sudden altitude variation of around 300 feet during cruise. According to the latest figures, 20 passengers and four cabin crew members were injured.

The aircraft subsequently stabilised and landed safely in Delhi.

Pilot Tested Positive For Marijuana

The probe has also come under scrutiny after the pilot-in-command reportedly tested positive for marijuana during confirmatory laboratory testing.

Both pilots underwent mandatory psychoactive substance testing following the incident and have been removed from the flying roster pending the investigation.

However, the AAIB has cautioned against drawing conclusions from individual pieces of evidence while the investigation is underway.

AAIB Examining Technical And Human Factors

The AAIB said it is examining flight data, aircraft systems, operational and maintenance records, medical information and other evidence linked to the incident.

The bureau has stressed that the investigation is independent and evidence-based, with all available evidence to be assessed together before any conclusions are reached.

France’s aviation investigation agency BEA and technical representatives from Airbus are assisting the AAIB under international aviation investigation protocols.

The latest maintenance report adds a significant technical aspect to the probe, with investigators examining the sequence of hydraulic warnings, autopilot disconnections and other system alerts alongside flight data and operational, medical and human-factor evidence.