- Maintenance report showed Air India flight AI2379 had multiple hydraulic system warnings during cruise
- The flight lost 300 feet altitude suddenly, injuring 13 passengers and 4 crew members
- Air India initially blamed turbulence but later removed this from their official statement
A maintenance report printed out in the cockpit of Air India aircraft from Phuket to Delhi, which experienced a sudden loss of altitude of 300 feet during its cruise phase injuring several passengers, indicates that the aircraft had suffered a series of hydraulic faults. The report was published at 11:14 am on August 4, after the flight landed in Delhi.
Two hours later, at 1:14 pm, Air India issued a statement where they attributed the crisis onboard the aircraft to a ''brief in-flight turbulence-related event during cruise, resulting in a momentary change in altitude.''
The airline said there have been no serious injuries and a small number of passengers and crew members with minor injuries requiring medical assessment have been taken to a medical facility at the airport for precautionary examination.
Five hours later, at 6:55 pm, the airline updated their earlier statement, taking out the word turbulence but still downplaying the significance of what had happened.
Read | Inside The Cockpit: What Went Wrong On Air India's Phuket-Delhi Flight
"Earlier today, Air India flight AI2379 operating from Phuket to Delhi experienced a sudden loss of altitude during cruise. After the momentary event, the aircraft continued normally and landed safely in Delhi at 11:07 hrs IST. The Airbus A-320 NEO aircraft was carrying 137 passengers and eight crew members. Of these, 13 passengers and four crew members sustained injuries and were taken to hospital for medical evaluation," the updated statement read, without mentioning any hydraulic failures.
An A-320 NEO aircraft normally runs on three separate hydraulic systems, so that if one fails, the other two can still power the flight controls, landing gear, and brakes.
On this Air India flight, warnings appeared showing low pressure in all three systems at 9:32 am, along with low fluid levels in two of the reservoirs.
Hydraulics are what let pilots physically move the control surfaces of the plane - losing multiple systems together is far more serious than losing just one, since the backup systems are also being affected.
Adding to the troubles, the autopilot also switched off at around the same time, at 9:32, and a fault was flagged in the left and right elevator controls (which help the plane pitch up/down), the report indicates.
Shortly after, two emergency exit door warnings were triggered - one at 9:33 am (right front door) and another at 9:35 am (right rear door).
Then at 10:16 am, Engine 1's anti-ice system showed a fault linked to a valve pressure issue, and the autopilot disconnected again at 10:52 am.
It's worth stressing that a "warning" on this kind of report doesn't necessarily mean total system failure. Modern aircraft are built with layers of redundancy and pilots are trained for exactly these scenarios, but a cluster of hydraulic and flight-control warnings happening together is exactly the kind of event that maintenance and safety teams would want to investigate closely.
At no point does the Air India statement mention that the aircraft encountered serious technical issues.
Read: Turbulence Or Something Else? Probe Widens In Air India 300-Foot Plunge Case
The other part of this report deals with the pilot in command who, sources say, had tested positive for psychoactive substances during the post-flight screening in Delhi.
Another test was conducted some time later, and sources said on Tuesday that this was also positive. Specifically, the test reportedly confirmed that the pilot had smoked marijuana, commonly known as weed.
The pilot in command of the plane was on medication for "sleep difficulty", as per the airline's internal flight safety report accessed by NDTV.
"I disclose, for completeness, that I had separately been experiencing sleep difficulty over a preceding period, related to personal circumstances, for which I had been prescribed medication by my family doctor," the pilot said in a flight safety statement.
The sources said the pilot was not in his seat with the co-pilot in command of the plane when it plummeted 300 feet.
The pilot floated up, as did things in the cockpit, and this is when people who were not strapped in at the back of the plane suffered serious injuries.
Both pilots have been derostered pending an inquiry.
