Air India flight AI2379, an Airbus A320neo operating the Phuket–New Delhi route, temporarily lost control of its primary flight surfaces for approximately four seconds on 4 August after failures were recorded across all three of the aircraft's hydraulic systems, according to a preliminary assessment by Airbus. The incident caused the aircraft to drop roughly 300 feet in altitude, injuring at least 24 passengers and crew members.

What the Flight Data Recorder Revealed

According to Airbus's analysis of the aircraft's Digital Flight Data Recorder (DFDR) — data transmitted to the manufacturer's AIRTAC technical support centre in Toulouse — the aircraft's elevators and ailerons, which govern pitch and roll, lost normal hydraulic control during the four-second window. Spoiler functions were also reportedly affected during the same period.

During that interval, the elevators and ailerons drifted without pilot command as the aircraft registered abnormalities across all three hydraulic systems, per Airbus's initial reading of the flight data. The autopilot subsequently disconnected, and the co-pilot — who was at the controls at the time — pushed the side-stick forward after the aircraft reportedly issued stall warnings.

Why the Pilot's Input Did Not Work Immediately

With hydraulic power temporarily unavailable, the co-pilot's control inputs did not produce the expected nose-down response. Once hydraulic systems recovered seconds later, the inputs took full effect, resulting in a sharp downward trajectory. Several passengers and cabin crew members were thrown upward inside the cabin, accounting for the injuries reported.

The aircraft was carrying 145 people in total — 137 passengers and eight crew members — at the time of the incident.

Pilot Drug Test and Airline Response

In a separate but related development, the pilot-in-command of flight AI2379 subsequently tested positive for marijuana in a confirmatory drug test, according to reports. The positive result adds a layer of regulatory and safety scrutiny to an incident already under examination for its technical causes.

Separately, Air India announced on 13 August that it has begun mandatory drug screening of all group pilots — a measure that appears to have been accelerated in the wake of the 4 August incident.

Broader Safety Context

A simultaneous failure of all three hydraulic systems on a commercial aircraft is an exceptionally rare event. Modern airliners like the A320neo are designed with redundant hydraulic circuits precisely to prevent total loss of flight surface control. This incident raises questions about whether the hydraulic failures were sequential or concurrent, and what triggered the cascade — details that India's aviation regulator, the Directorate General of Civil Aviation (DGCA), is expected to examine as part of its formal investigation.

This comes amid growing scrutiny of Air India's operational safety standards following its privatisation and ongoing fleet expansion. A full investigation report from Indian and international aviation authorities is awaited.