NEW DELHI — An Air India Airbus A320 that abruptly lost about 300 feet of altitude during a Phuket-to-Delhi flight last week is being investigated after reports that all three of the aircraft's hydraulic systems may have failed, a development that could add a new dimension to an inquiry already involving turbulence and crew performance.
Flight AI2379, operated by an A320 registered as VT-EXO, was cruising on Aug. 4 when it experienced the sudden altitude loss before stabilising and continuing to Delhi, according to information reported by India's aviation authorities and the airline. The aircraft landed safely.
Air India said the incident injured passengers and crew. Reuters reported that eight passengers and four crew members were injured, while other Indian media reports have cited higher figures as assessments of injuries continued.
The Aircraft Accident Investigation Bureau (AAIB) has taken custody of the aircraft's flight data recorder and cockpit voice recorder as part of its investigation. Airbus and France's Bureau of Enquiry and Analysis for Civil Aviation Safety (BEA) are also due to assist the inquiry, officials said.
The reported hydraulic-system failure has not been established as the definitive cause of the altitude loss. Investigators are expected to examine flight-data recordings, cockpit communications and aircraft systems before reaching conclusions.
The A320 family uses hydraulic systems to operate or assist several flight-control and other aircraft functions. A complete loss of hydraulic pressure would be a significant technical event, but the precise relationship, if any, between the reported system malfunction and the aircraft's sudden descent remains under investigation.
The incident has also drawn scrutiny after India's civil aviation ministry said the captain initially tested positive for psychoactive substances in a screening conducted after the flight. The ministry said further laboratory testing would be required to confirm the result.
Airbus said it would send specialists to India to support the investigation, while the AAIB continues to examine the circumstances surrounding the incident.
The aircraft remained safely on the ground after arriving in Delhi. Investigators have not yet publicly assigned a final cause for the altitude loss.
