Air India Flight To Vienna Faces 'Stall,' 'Don't Sink' Warnings Days After Ahmedabad Crash; Pilots Grounded, Says Report

Just 38 hours after the deadly Ahmedabad crash, Air India flight AI 187 received critical 'stall' and 'don't sink' warnings, leading to a 900-foot altitude loss. Pilots are grounded as DGCA investigates mounting safety concerns.

Wreckage of Crashed Air India Plane Moved in Ahmedabad (IANS)

Only 38 hours after the deadly Air India flight AI 171 crash at Ahmedabad, which had killed more than 260 people on June 12, another Air India long-range flight, AI 187 to Vienna, suffered a serious in-flight incident. The Boeing 777 allegedly prompted severe "stick shaker" and "don't sink" alerts from its Ground Proximity Warning System (GPWS), losing some 900 feet of altitude while climbing out of Delhi.

Despite the alarming warnings, pilots managed to stabilise the flight and land safely to Vienna, a Times of India report revealed. A thorough probe into the incident has been initiated by the Directorate General of Civil Aviation (DGCA). Air India's safety chief has been called in and both pilots have been taken off flying duties until the conclusion of the probe.

Warnings During Climb Amid Stormy Weather

Flight AI 187 (VT-ALJ) took off from Delhi at 2:56 am on June 14, under stormy weather conditions in the capital. Sources involved in the case reported that "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 about 900 feet during climb."

The "stick shaker" system is intended to warn pilots with an immediate tactile and auditory warning of the approach of an aerodynamic stall, requiring the pilot to immediately take corrective action. The "don't sink" GPWS warning alerts against unwanted loss of altitude following takeoff. The timely response of the crew permitted them to stabilize the plane and proceed with the flight, which took 9 hours and 8 minutes. The plane subsequently made a scheduled technical stop in Europe before proceeding to Toronto with a new crew owing to continued airspace restrictions.

Significantly, Delhi-Vienna's post-flight report had quoted only "stick shaker due to turbulence after takeoff," without specifying the other critical warnings. A closer scrutiny of the flight data recorder (DFDR), probably under increased monitoring in the wake of the recent crash, revealed the "don't sink" GPWS warning and a stall warning that had not been documented before. 

The AI 171 Ahmedabad Tragedy

This accident with AI 187 follows within days of the disastrous Air India Flight AI 171 crash. The Boeing 787-8 Dreamliner, flying from Ahmedabad to London Gatwick, had crashed just minutes after takeoff on June 12, killing 241 of the 242 passengers and crew on board, along with several ground fatalities. It is the first fatal crash of a Boeing 787-8 Dreamliner in the world.

India's Aircraft Accident Investigation Bureau (AAIB), the top agency for investigating aviation crashes in the country, is spearheading the investigation of the Ahmedabad crash. The cockpit voice recorder (CVR) and flight data recorder (FDR), also popularly referred to as black boxes, have been retrieved from the crash site and sent to Delhi for rigorous analysis.

The government has officially stated that the data of the black boxes are already being analysed, as investigators painstakingly attempt to recreate the final moments of the plane in order to determine the exact cause of the June 12 disaster. Several possibilities, such as sudden engine failure, power malfunction, system faults, or pilot mistake, are being scrutinised with extreme intensity. Aviation professionals state that only thorough examination of the black box information will give clear answers. The back-to-back occurrences have brought Air India under greater regulatory and public scrutiny for its safety procedures during operation.