COCKPIT voice recorder of the ill-fated Bell Helicopter, which crashed killing Andhra Pradesh Chief Minister on September 2, 2008, clearly speaks about poor flight planning and coordination between the pilot and co pilot of the helicopter.
Directorate General of Civil Aviation (DGCA) submitted a comprehensive 139 pages report to the civil aviation department mentioning technical snag to be the reason for the crash of the YSR’s helicopter.
In its report – DGCA categorically mentioned that the co-pilot of the chopper was constantly asking the pilot to go around that is to indicating emergency situation that is proximity to the ground. The co pilot was repeated making the calls for go around. Meanwhile the Engine Control Unit (ECU) readout showed that during the last 14 seconds the rate of descent was in excess of ten thousand feet/minute indicating that the helicopter during this period when the co-pilot was giving callouts for go around was encountering very high rate of descent. Thereafter helicopter crashed due to loss of control resulting in high rate of descent in down draught. The helicopter impacted the ground and all occupants on board died due to crash injuries.
The cockpit voice recorder transcript says that the pilot in command was well aware of the repercussions of bad weather and instructed co-pilot to keep his hand under the collective to safe guard against exceedance of torque and up and down draughts and turbulence.
The crew got so engrossed with the emergency and lost situational awareness of extreme bad weather ahead. The worst part was the pilot and co-pilot had poor cockpit resource management any given stage of flying.
GRAPHIX Flight Recorders
The helicopter is equipped with CVR but not DFDR (neither it is required to be equipped with DFDR). The CVR was recovered in damaged condition. It was decoded at NTSB facility at Washington D.C in presence of representative of committee of inquiry.
Salient Points from the CVR transcript are as under:
1.The Flying Crew was well aware of inclement weather enroute as the same was discussed, visually observed and interpreted the weather Radar picture throughout the flight.
2.The Crew was in contact with Hyderabad approach on VHF frequency till they were asked to change over to Chennai control after establishing the contact with Chennai on HF frequency.
3.The Crew was not sure about Chennai frequency and was debating among themselves about the Chennai frequency given to them by Hyderabad approach which shows poor flight planning.
4.The PIC was well aware of the repercussions of bad weather and instructed the Co-Pilot to keep his hand under the collective to safe guard against exceedance of Torque and up and down draughts and turbulence.
5.The Crew noticed transmission pressure display on IIDS and failed to correlate with other indication associated with it. They wanted to refer the emergency encountered with the help of emergency checklist but could not locate the emergency either in the emergency checklist or in the Flight Manual.
6.The CVR transcript shows that they were expecting some improvement in weather conditions after crossing Krishna River which was flowing at right angle to the flight path in hilly region.
7.The Crew got so engrossed with the emergency and lost situational awareness of extreme bad weather ahead.
8.There were repeated warnings from Co-pilot to Go Around due to close proximity of ground which he may have realized either with the help of Radio altimeter or may have sighted the obstruction momentarily, the PIC failed to react to the situation.
9.The CVR transcript shows that there was poor CRM amongst the Crew at any given stage of flying.