Air India A320 Briefly Lost Key Flight Controls During 300-Foot Drop

NEW DELHI — An Air India (AI) Airbus A320neo briefly lost the use of its elevators and ailerons during a sudden 300-foot descent on August 4, according to a preliminary Airbus analysis that sharpens the technical focus of the investigation into Flight AI2379.

All three of the aircraft's hydraulic systems registered pressure losses in rapid succession, leaving the four primary control surfaces unavailable for about four seconds, Reuters reported after reviewing the Airbus assessment. Pressure returned within seconds.

The first officer made a full nose-down sidestick input but initially received no direct response from the elevators or ailerons, Reuters said. The aircraft then descended roughly 300 feet before the crew recovered control.

Twenty-four passengers and crew members were injured. Flight AI2379, operating from Phuket International Airport (HKT) to Delhi's Indira Gandhi International Airport (DEL), later stabilized and landed safely with 145 people aboard, according to the Associated Press's account of the incident and government response.

Airbus has not identified what triggered the pressure losses. Its assessment does not establish whether the aircraft physically lost pressure in each circuit or whether a sensing, switching, wiring, or indication problem produced the recorded sequence.

Three Systems, One Unresolved Sequence

The A320 Family uses separate Green, Blue, and Yellow hydraulic circuits. Each normally operates at 3,000 pounds per square inch and supplies part of the aircraft's flight-control system, according to Airbus technical material describing the architecture.

Green and Yellow normally receive pressure from engine-driven pumps. The Blue system uses an electric pump and can receive emergency power from a ram air turbine. A power transfer unit can transfer hydraulic power between Green and Yellow without moving fluid from one reservoir to the other, Airbus explains in its A320 dual-hydraulic-loss guidance.

That separation provides redundancy. A fault affecting one circuit should not automatically remove every hydraulic source serving the primary flight controls. A rapid pressure-loss sequence across all three therefore directs investigators toward the recorded data, the condition of the hydraulic components, and anything capable of affecting more than one system.

It would be premature to label the event a physical triple hydraulic failure. Airbus's reported inspection request covers pressure-sensing components and electrical paths as well as hydraulic hardware, indicating that the investigation has not settled whether the readings reflected actual pressure loss or another system problem.

Why the Sidestick Input Did Not Immediately Move the Surfaces

The A320 uses digital fly-by-wire controls. A pilot's sidestick movement is processed by flight-control computers, which send electrical commands to hydraulically powered actuators. Airbus describes that signal path in its fly-by-wire safety explainer.

During the four-second interval identified in the assessment, the elevators and ailerons had no reported hydraulic availability to act on the first officer's command. The absence of an immediate surface response is evidence of the interruption. It does not by itself identify what removed the pressure or what caused the aircraft's initial pitch change.

Investigators will need to align the sidestick position with hydraulic-pressure data, actuator and surface positions, aircraft attitude, acceleration, autopilot status, and flight-control-computer messages. The timing matters at fractions of a second: it should show when the controls became unavailable, when pressure recovered, and how the aircraft responded as authority returned.

Airbus Requests Component and Structural Checks

Reuters said Airbus asked Air India to inspect hydraulic components, sensors, and switches, with wiring checks also under consideration. Maintenance performed before the August 4 flight is another open part of the inquiry.

No inspection result was public when this draft was prepared. Airways also found no Airbus instruction extending the checks to other A320 operators. Any fleetwide action would require a separate manufacturer or regulator communication; the airline-specific assessment reviewed by Reuters does not amount to one.

The manufacturer also advised checking the aircraft for possible structural damage because loads during the event exceeded specified limits, Reuters reported. An exceedance does not prove that damage occurred. It triggers an engineering and maintenance assessment to determine which areas require inspection.

Airbus says recorded data from a high-load event can guide the maintenance work by identifying the parts of an aircraft most likely to have been stressed. Its guidance on high-load analysis notes that the review can run alongside structural inspections and does not itself authorize an aircraft's return to service.

Investigation Now Centers on the Recorded Pressure Loss

India's Aircraft Accident Investigation Bureau has classified the occurrence as a serious incident, Reuters reported. Airbus and France's Bureau of Enquiry and Analysis for Civil Aviation Safety are providing technical assistance to the Indian investigation.

The AAIB inquiry includes flight data, aircraft systems, maintenance and operational records, medical information, and interviews, AP reported. The preliminary Airbus assessment adds a specific sequence for investigators to test; it is not a finding of probable cause.

Reuters also reported that the captain tested positive for marijuana in a confirmatory test. No authority has linked that result to the hydraulic-pressure losses, the temporary control interruption, or the aircraft's motion. The medical and technical evidence belong to separate lines of inquiry unless investigators establish a connection.

The central question is now narrow but unanswered: why did three independent systems register pressure losses within seconds of one another, and why did pressure return? Component inspections, wiring checks, maintenance history, and validated recorder data will determine whether the event began in the hydraulic system, its monitoring architecture, or somewhere else.

The Airbus aircraft VT-EXO (MSN 8470) was officially delivered to Air India on November 21, 2018. The airframe is leased to the airline from Macquarie AirFinance.