New Delhi: The Directorate General of Civil Aviation (DGCA) has grounded 2 pilots who operated the Delhi-Srinagar IndiGo flight which was caught in turbulence on Wednesday evening. The flight reportedly flew through a hailstorm. The suspension came as new details emerged regarding their interaction with air traffic controllers in Lahore and Srinagar amid the turbulence. There were 227 people on board the aircraft at the time.
Aircraft plummeted more than normal descent rate: DGCA
The DGCA in an internal probe found that Airbus A321 Neo at one point plummeted at 8,500 feet per minute, reported Hindustan Times. This was more than 4 times the normal descent rate. This happened because multiple flight control systems failed, even as pilots received a warning regarding a stall, which means a condition in which an aircraft begins to lose altitude and overspeed conditions as they fought to regain control.
There were also details about how the pilots approached the air traffic control in Pakistan, after the emergency. They contacted Pakistan ATC after Indian air traffic controllers bound by the recent air space restrictions over Pakistan, advised the pilots to not fly westwards. But they also asked the 2 pilots to control Lahore ATC directly. Contact frequencies were also made available to the pilots for the same. The neighbouring country however denied the request.
A DGCA official quoted by Hindustan Times said, “The matter is under investigation by the DGCA. As part of the investigation, the two pilots are grounded pending investigation.”
Talking abouut the seriousness of the issue, Civil Aviation Minister Ram Mohan Naidu said, “We are looking into the incident, but in the meantime from the information that I have, I would like to appreciate the efforts of the pilots and the crew who have been very composed in the way they have handled even in that weather that the flight has gone through.”
He also expressed gratitude towards the pilots and the crew that no untoward incident happened and all people onboard were safe. But he added that a thorough investigation will be conducted in the matter, to know exactly what happened.
Near-death experience: Passengers onboard IndiGo flight
Meanwhile passengers onboard the IndiGo flight, 6E-2142 which was caught in turbulence described the experience as “near death”. The plane had departed the Indira Gandhi International Airport in Delhi at 4:55 PM and landed in Srinagar at 6:25 pm. The hailstorm struck the plane near Pathankot, when the plane was cruising at 36,000 feet.
Seeing the situation that they were in, the pilots requested the northern control, under the Indian Airforce, for permission to deviate towards the left, which is the international border. The permission was immediately denied. The desperate crew then contacted Lahore ATC to enter their airspace, but their request was once again turned down.
The denial was due to a NOTAM issued by both India and Pakistan for aircraft registered in the other country.The IAF denied permission to deviate westward due to the NOTAM in place, and was a kind of an advisory given the volatile political and military situation experienced at the border recently.
The crew initially tried to return to Delhi, but when that failed, they decided to penetrate the weather, said DGCA. They were flying close to the thunderstorm cloud. The DGCA stated, “While in thunder storm cloud, warnings of angle of attack fault, alternate law protection lost, backup speed scale unreliable were triggered. Due to updraft and down draft encountered by the aircraft the autopilot tripped and aircraft speed had wide variations.”
Put simply, several of the aircraft’s computerised systems failed, which forced the pilots to fly manually through violent turbulence. They also did not have the reliable instruments or the normal protections that prevent a modern airliner from stalling or exceeding its structural limits. The crew flew the aircraft manually till they exited the hailstorm. The flight descended at a speed of 8500 feet per minute, whereas the normal descent is 1,500 to 2,000 feet per minute, said DGCA.
After exiting the hailstorm, and regaining control of the plane, the pilots declared emergency. The aircraft then declared PAN PAN to Srinagar ATC and requested radar vectors be activated. They finally managed to land safely with the auto thrust operating normally.
PANPAN call is an international urgency signal indicating serious difficulty requiring assistance, and is one level below MAYDAY distress call. No passenger was injured post the turbulence but the aircraft’s nose was damaged.
