38 hours after AI 171 crash: AI Boeing 777 got 'stall, ground proximity & don't sink warning' on take off from Delhi

NEW DELHI: Yet another Air India wide body aircraft had a close shave within 38 hours of the deadly June 12 AI 171 crash in Ahmedabad. Immediately after taking off from Delhi in the early hours of June 14, a Vienna-bound Boeing 777 got stall warning . It also got ground proximity warning system’s (GPWS) don’t sink caution, asking pilots not to lose altitude as the aircraft operating as AI 187 had witnessed altitude loss of about 900 feet during climb.

Luckily, pilots recovered the aircraft from this precarious situation and safely proceeded to the destination. The Directorate General of Civil Aviation (DGCA) is probing the incident; have already summoned AI’s head of safety for this case and both the pilots have been taken off flying duty pending the investigation.

According to flight tracking sites, the B777 (VT-ALJ) took off at 2.56 am on June 14 in bad weather. Delhi was witnessing a thunderstorm that time. “The aircraft was involved in an inflight occurrence of stick shaker and GPWS caution. Soon after takeoff, stick shaker warning and GPWS don’t sink caution appeared. Stall warning came once and GPWS caution came twice. There was an altitude loss of around 900 feet during climb. Subsequently, the crew recovered the aircraft and continued the flight to Vienna,” said officials aware of the incident.

Stick shaker refers to the control column on the flight deck shaking and making a noise to indicate something is not right and that the pilots’ attention to the situation is urgently required. In this case the pilots did that and saved the day. The flight landed safely in Vienna after 9 hours and 8 minutes. After this technical halt in Europe necessitated by longer routes taken these days due to enroute airspace closures, the aircraft then proceeded to Toronto with another set of crew members.

However, the flight report for Delhi-Vienna sector only had the “stick shaker due turbulence after takeoff mentioned and not the other occurrences in detail,” said officials. When authorities examined the B777’s flight data recorder (DFDR), possibly as part of the enhanced surveillance ordered by the DGCA after AI 171 crash, the other occurrences of GPWS don’t sink caution and stall warning appearing came to light, they say.

An AI spokesperson said: “Upon receipt of the pilot's report, the matter was disclosed to DGCA in accordance with regulations. Subsequently, upon receipt of data from the aircraft's recorders, further investigation was initiated. The pilots have been off-rostered pending the outcome of the investigation.”

Both the pilots have been off rostered (taken off flying duty) pending investigation. The regulator has taken a very stern view on the June 14 incident. It is learnt AI head of safety was summoned on this issue.

Following AI 171 crash, the DGCA had on June 17 raised “concern regarding recent maintenance-related issues” reported by Air India and directed the airline to strictly focus on safety while “strengthen(ing) internal coordination across engineering, operations, ground handling units.”

Multiple industry insiders said: “Old Air India (PSU time) did not have comfortable planes running on time but safety was never an issue. Now planes, at least the narrow body fleet, are better but passengers are apprehensive about safety after the terrible AI 171 crash. The new management and the new owner need to win back passenger and employee trust at the earliest by doing all it takes."