Air India Phuket-Delhi flight lost hydraulic systems, take action over pilot drug use: AAIB

The pilot-in-command (PIC) of the August 4 Phuket-Delhi Air India flight, which suffered a sudden loss of altitude during cruise and left 20 passengers and four crew members injured, tested “non-negative” for a psychoactive substance in a confirmatory test, a preliminary Aircraft Accident Investigation Bureau (AAIB) report released on Friday said. The Airbus A320neo with 137 passengers suffered an “altitude upset” after losing all three hydraulic systems within seconds while cruising at 36,000 feet, the agency found.Twenty passengers and four crew members were injured when the Phuket-Delhi Air India flight suffered a sudden loss of altitude. (ANI)The report said the PIC was the pilot monitoring, or crew member in a two-pilot aircraft not actively handling the primary controls, and the copilot tested negative in both tests. It did not establish any link between the psychoactive substance finding and the altitude upset. “Detailed investigation regarding technical and other aspects is underway.”ALSO READ | ‘Safety remains highest priority’: Air India after Delhi-bound flight's pilot tests ‘non-negative’ for drug useAAIB recommends DGCA actionThe AAIB recommended that the regulator, Directorate General of Civil Aviation (DGCA), take appropriate action as deemed fit to prevent abuse of psychoactive substances. The AAIB called their use a serious concern and said a detailed probe regarding technical and other aspects remains underway.The report said the co-pilot responded to the situation before the PIC took over the controls, and the aircraft recovered and landed safely in Delhi. It added that both pilots underwent post-flight medical examination in Delhi, as the flight had originated outside India.The report said their breathalyser tests for alcohol were satisfactory. It added that both were subjected to a psychoactive substance detection test. “The sample of PIC was found non-negative. Subsequently, blood samples of both the flight crew were sent to the pathological laboratory for confirmatory test. The confirmatory test report of PIC was found non-negative, whereas the sample of the copilot was found negative in both tests.”The report said the aircraft was cruising at FL360 and seat belt signs were off at the time of the event. It said the crew assessed the situation and decided to continue to its planned destination, and did not divert to the nearest airport. “The flight crew or ATC [Air Traffic Controller] reported no adverse weather.”The crew contacted ATC Delhi and sought medical priority. The aircraft landed safely at 11am IST, and taxied on its own power to the parking bay and parked. The report said four of the people injured seriously were hospitalised. It added cabin, mainly the overhead stowage bins and ceiling panels, suffered damage.The report said the flight took off from Phuket in Thailand at 7.11am IST and initially reported no abnormalities. At 9:10am, it entered the Kolkata Flight Information Region. The aircraft’s flight-control system detected a loss of the green hydraulic system at 09:32 am. Four seconds later, it detected the loss of the blue and yellow hydraulic systems.ALSO READ | 'Saw my sister thrown up in air, blood on man's face': Air India Phuket-Delhi passengers recall horrorHydraulic systems power components such as wheel brakes, nose wheel steering, landing gear retraction, flight control surfaces, windshield wipers, and propeller pitch control.At 4.02am, the autopilot disengaged, and a continuous repetitive chime sounded. Three seconds later, the stall warning was triggered for two seconds. “...the aircraft encountered altitude upset. Initially, it gained 372 ft and fell by 292 ft from its assigned FL360 during the event,” said the AAIB report. It added that the blue hydraulic system was recovered around 09:32am. A few seconds later, the yellow and green hydraulic systems were recovered, leading to the recovery of the control surfaces and allowing the aircraft to return to normal operating condition.The AAIB said aircraft maintenance personnel generated the Post Flight Report, which was examined to check the in-flight warning and failure messages. It recorded warnings of low pressure in the green hydraulic system followed by the blue and yellow systems, the autopilot switching off and faults involving the left and right elevators. The report recorded low-level warnings for the yellow and blue hydraulic reservoirs.The report said the aircraft is equipped with Solid-State Flight Data Recorders and a Solid-State Cockpit Voice Recorder. “Post-event, both the flight recorders were removed from the aircraft and were brought to AAIB headquarters for further analysis,” the report said.The report said the investigation team inspected the aircraft, collected hydraulic components and fluid samples, and obtained fuel and oil samples for examination. AAIB collected maintenance and operational records and relevant information from Delhi and Kolkata ATC.The AAIB said that technical experts from Airbus inspected the aircraft between August 13 and 15. It added that some hydraulic components and hydraulic samples were collected for further analysis.In a statement, Air India cited the preliminary report and said the airline will continue to extend full cooperation to the investigation, including access to operational, maintenance and technical records. It added that it started voluntary testing of 100% of its pilots as a further step to reinforce its safety-first approach following the incident. “The airline maintains zero tolerance for any breach of safety, fitness or regulatory requirements and will take appropriate action wherever warranted.”The government is considering random drug tests for all pilots annually after Air India voluntarily began testing 100% of its pilots starting August 13. The rules currently provide for 10% across the overall pilot network.Airlines Pilots’ Association India (ALPA India) president Sam Thomas said the report is on expected lines. He called for expeditious return of flying status of at least the co-pilot. “...we also want the opinion of Airbus on why all the hydraulics failed, albeit for a short period of time, and what modifications are being done so that it does not recur again,” he said. “We also want a time-bound final report so that everybody is aware of what necessary actions have to be taken on the other Airbus 320 fleet.” He called for action in case of a proven second-time positive drug test of a pilot.An Airbus spokesperson said the aircraft manufacturing company continues to provide full technical assistance to the relevant investigating authorities. “We are actively supporting the airline and providing further information as it becomes available.”