Mistake by crew, glitch hit Rahul Gandhi’s flight in April: DGCA report

A Directorate General of Civil Aviation (DGCA) investigation report released Friday blamed an error in the Flight Control Computer and a delay by the crew in dealing with the situation for the problems encountered by a chartered flight ferrying Congress President Rahul Gandhi to Hubbali in Karnataka. The investigation was ordered after the Congress said at the time that it suspected sabotage.

On April 26, in the middle of the campaign for the Karnataka assembly elections, Gandhi took off from New Delhi for Hubbali. One and a half hours later, his chartered flight faced a technical snag and Gandhi, in his own words said later that he thought “it’s all over”. After that incident Gandhi decided to visit Kailash Mansarovar, for which he left on Friday.

The DGCA report, released on Friday, blamed the pilot for reacting late after the auto-pilot tripped, creating “panic and scare for the passengers in the cabin”.

The flight data recorder analysed by DGCA confirmed that the Ligare Aviation Falcon 2000 aircraft VT-AVH was cruising at 41,000 feet when the auto pilot tripped. The aircraft started tilting to the right and also lost height. The pilot took 24 seconds to control the situation, but the DGCA report said in its report that the “‘incident was survivable”.

“When the auto pilot tripped, the crew did not realize that the aircraft has gone into a bank with yaw damper failure,” the report said, referring to a part that prevents the aircraft from rolling and banking. It is mandatory that the yaw damper remain operational on certain types of aircraft flying above specified heights. The report says that this failure was likely caused by “intermittent behaviour” of Flight Control Computer 2.

According to the report, “the crew only realized (this had happened) when the bank angle warning came at 45 degree i.e after 13 seconds of autopilot disengagement”. The bank angle warning comes on when the aircraft’s tilt exceeds a certain angle. The report further states that “the bank angle kept on increasing with altitude loss and reached a maximum of 64.95 degrees i.e 15 seconds after the auto pilot disengagement.”

By then, the aircraft had also lost height by 735 ft . The crew reacted and “the aircraft finally recovered to straight and level flight after 24 seconds from the autopilot disengagement,” the DGCA report said, adding that the “lack of situational awareness” by the crew was a contributory factor for the incident.

According to a pilot with a leading airline who asked not to be identified, the right angle for a small plane such as the one Gandhi was on is 30 degree and the warning must have been set at 45 degree.

“The pilot should have noticed on screen the yaw damper warning; it was probably the yaw failure which leads to tripping of auto plot. The aircraft was not only tilting but was also going down. However, since they were cruising at a decent height, they managed to rectify the mistake,” added this person. The aircraft was at around 41,000 ft when the incident happened.

“From the above it is inferred that the crew actions were slightly delayed to take the corrective actions,” the DGCA report said.

“Does the report not virtually say that there was serious possibility of an imminent accident? Good fortune, good luck and God saved it. An accident in this situation means almost certain death,” Congress spokesperson Abhishek Manu Singhvi said in response to the report.

The Hyderabad ATC was monitoring plane on radar and noticed descend of aircraft and immediately called up VT-AVH . The pilot intimated that he had descended due to technical reasons and later informed ATC that the autopilot had tripped. When the aircraft banked to the right and descended the pilot did not declare any emergency to Hyderabad controller.

The pilot thereafter flew the aircraft manually and got in touch with Hubbali ATC at around 70 nautical miles and landed at 11.33am.

First Published: Aug 31, 2018 18:36 IST