Both pilots of the twin-engined Bell 430 helicopter which crashed in the Nallamala Hills of Andhra Pradesh on September 2 last year killing Chief Minister Y.S. Rajasekhara Reddy never thought it fit to return to Hyderabad or divert the copter to a nearby location despite the inclement weather.
They were hopeful of some improvement after they crossed the Krishna river at 9.20 a.m., 42 minutes after take-off from Begumpet airport but the weather never cleared. Five minutes later, there were repeated ‘callouts’ from the co-pilot “Go Around,” thereby indicating some problem – a hill feature in the vicinity. But, it was too late.
Technical data gleaned from the Cockpit Voice Recorder (CVR) or the ‘black box’ during the last 14 seconds showed that the rate of descent was over 10,000 feet a minute, pointing to failure of critical systems — the main rotor and the power turbine were going too fast while the torque was dropping. Apparently, a severe downdraught was encountered by the helicopter and it impacted the hills killing the Chief Minister, his two aides and the pilots. In fact, lightning location data revealed a storm centre that appeared to be in the helicopter’s path at the time of the disaster.
The poor judgment shown by Pilot Capt. S.K. Bhatia and Co-pilot M.S. Reddy is among the significant causes pinpointed by the four-member enquiry committee constituted by the Centre with Pawan Hans CMD R.K. Tyagi as chairman. They encountered a snag in the transmission of oil pressure. They got so engrossed in the emergency checklist to resolve the snag for a vital six minutes that they “lost situational awareness of the extreme bad weather ahead.”
Capt. Bhatia and Capt. Reddy drew more flak in the Tyagi Committee’s 139-page report. “The CVR transcript showed that there was poor Crew Resource Management among them at any given stage of flying.” They noticed the snag in transmission pressure on the Integrated Instrument Display System but failed to co-relate it with other indications associated with the snag. Finally, they could not refer the emergency either in the checklist or in the Flight Manual.
In a significant conclusion, the report said: “The helicopter was not airworthy when it was released for flight on September 2, even though this was not a contributory factor to the accident.” Yet, the Certificate of Airworthiness of the helicopter was current and valid. Also, the A.P. Aviation Corporation Limited did not maintain any snag register to allow analysis of the defects. Besides, when the two engines were swapped on May 30, 2009, the reasons for their removal were not recorded in the log book indicating “the casual attitude of the maintenance personnel.”