Hydraulic pressure, autopilot disconnect: Turbulence-hit Air India Phuket-Delhi flight logged 9 warnings in a minute

On August 4, Air India flight AI2379 experienced a sudden loss of altitude, plummeting 300 feet, resulting in 24 injuries among 20 passengers and four crew members. The Airbus A320, registered as VT-EXO, was en route from Phuket to Delhi when the incident occurred. The Aircraft Accident Investigation Bureau (AAIB) classified the event as serious, triggering an investigation.

Immediately after the incident, the Centralised Fault Display System logged nine warnings within a single minute. These alerts detailed low pressure in the Green, Blue, and Yellow hydraulic systems, low reservoir levels in the Yellow and Blue systems, an autopilot disconnect, and an elevator flight-control fault. The hydraulic systems of the aircraft rely on pressurized fluid to power heavy mechanical components.

Two emergency-exit door sensor warnings were recorded at 9:33 AM and 9:35 AM IST, while no further warnings related to the hydraulic systems or elevator were logged for the subsequent 43 minutes. An engine anti-ice fault was noted at 10:16 AM IST, followed by another autopilot disconnect at 10:52 AM IST. However, the second disconnect did not come with any hydraulic warnings.

The pressure readings fluctuated across different system combinations within the same minute, suggesting a temporary event rather than a sustained mechanical fault. This could indicate a sudden loss of altitude or rapid vertical movement, which briefly disturbed fluid within the hydraulic reservoirs. A prolonged mechanical issue would have likely generated additional warnings, including those indicating recurrence of the problem.

Flightradar24 data corroborates the altitude change occurring within the same minute as the warning cluster. The aircraft was initially flying at 36,160 feet when an anomaly was detected at 9:33 AM IST, subsequently descending to approximately 35,800 feet—a 360-foot drop. The pilot admitted to falling asleep for 30-35 minutes during the flight, visiting the restroom, and returning to stand behind the first officer.

He reportedly collided with the cockpit floor while discussing the air conditioning system. The first officer took control of the aircraft, and the commander served as the pilot monitoring. A cabin crew member in the observer seat assisted the commander in regaining control, marking the initial cockpit account of the incident.