Delayed reaction by pilots commanding the chartered flight which ferried Congress President Rahul Gandhi from Delhi to Hubballi in Karnataka had brought the aircraft dangerously close to a crash, aviation regulator DGCA said on Friday.
The Directorate General of Civil Aviation (DGCA) disclosed the operational lapses in its investigation report on the snag that hit the chartered flight operated on a Falcon 2000 aircraft VT-AVH on April 26.
On April 27, the regulator had set up a two-member panel to investigate into the cause of the snag reported in the aircraft. which was carrying Congress President Rahul Gandhi.
Protocol-wise, the DGCA investigates any technical snag on a VIP flight through a two-member committee.
As per the report, the flight suddenly lost altitude as the auto pilot disengaged while the aircraft heavily banked.
"Aircraft VT-AVH was in cruise flight at FL 410 (41,000 feet) near waypoint (BOGAT), the yaw damper failed indication came on Primary Flight Display (PFD) and the auto pilot disengaged. As the auto pilot tripped, both the crew got busy analysing the fault and did not realise that the aircraft has gone into a bank with the yaw damper failure," the report said.
The report, however, described the incident as "survivable".
"The crew only realised when the bank angle warning came at 45 degree. The bank angle kept on increasing with altitude loss and reached a maximum of 64.95 degrees," the report said.
The report pointed out that crew initiated corrective action to control the aircraft altitude "15 seconds after the auto pilot got disengaged".
"The PIC (pilot in command) actions were slightly delayed as he took over control manually only after the warning was activated. This delayed action caused the aircraft to reach high bank angle value and altitude loss which created panic and scare for the passengers in the cabin," the report said.
Accordingly, the report cited "yaw damper" failure which occurred due to intermittent behavior of FCC (flight control computer) 2, which caused the auto pilot to disengage and the aircraft went into excessive right bank with altitude loss, as the probable cause of the snag.
In addition, the report said that due to lack of situational awareness, "the crew actions to control the aircraft manually were slightly delayed". This was another probable cause for the incident.