A post-flight Centralised Fault Show System log from an Air India Phuket-Delhi flight that suddenly lost altitude and dropped 300 ft, leaving 24 individuals injured, revealed a collection of warnings linked to the plane’s hydraulic techniques, flight controls and autopilot.
The August 4 incident, which left 20 passengers and 4 crew members injured on flight AI2379, an Airbus A320 registered as VT-EXO, was labeled as severe and led to an investigation by the Plane Accident Investigation Bureau (AAIB).
The pilot’s preliminary post-flight drug screening was recorded as “non-negative”, that means the pattern had been flagged for additional testing. His confirmatory take a look at later returned constructive for hashish.
A number of warning indicators throughout plane plunge
The log, seen by HT, reveals 9 warning messages showing inside a minute at 9.32am IST, when the plane had crossed the Odisha coast after flying over the Bay of Bengal.
The warnings indicated low stress within the Inexperienced, Blue, and Yellow hydraulic techniques, in varied combos. In addition they confirmed low reservoir ranges within the Yellow and Blue techniques, an autopilot disconnect and an elevator flight-control fault.
Notably, the plane’s hydraulic techniques depend on pressurised fluid to transmit energy and function heavy mechanical elements.
Two emergency-exit door sensor warnings had been then recorded at 9.33am and 9.35am. No extra warnings involving the hydraulic techniques or elevator had been recorded for the next 43 minutes.
An engine anti-ice fault appeared at 10.16am, adopted by one other autopilot disconnect at 10.52am. Not like the primary disconnect, the second was not recorded alongside any hydraulic warnings. The log doesn’t present a cause for the disconnect.
The stress readings modified throughout totally different system combos inside the similar minute, somewhat than exhibiting a single system failing and remaining in that state. This might point out a brief occasion, reminiscent of a pointy vertical motion or sudden lack of altitude. Such an occasion can briefly transfer fluid contained in the hydraulic reservoirs, primarily based on a studying of the log by HT towards customary A320 fault-code references.
A sustained mechanical fault would seemingly have generated extra warnings, together with messages indicating that the difficulty had recurred.
Flightradar24 information locations the altitude change inside the similar minute because the cluster of warnings. The plane was flying at 36,160 ft when an altitude anomaly was recorded at 9.33am IST. It then descended to round 35,800 ft, representing a lack of about 360 ft, in response to Flightradar information.
Pilot slept 30-35 minutes throughout flight
The pilot informed investigators that he slept for 30 to 35 minutes in the course of the flight, went to the washroom after which returned to face behind the primary officer, in response to two individuals aware of his account to the AAIB.
They mentioned he was speaking concerning the air con system when the altitude occasion occurred and that he was thrown to the cockpit flooring. The primary officer was working the plane, whereas the commander was performing because the pilot monitoring, the 2 individuals mentioned.
A cabin crew member seated within the observer seat, which a departing pilot is required to assign when leaving the cockpit, helped the commander again up, the individuals mentioned. This was the primary detailed account from the cockpit crew about what occurred aboard flight AI2379.
The whole sequence of occasions contained in the cockpit couldn’t be independently confirmed by the pilots’ accounts to investigators.
