The pilots of Andhra Pradesh Chief Minister Y S Rajasekhara Reddy's ill-fated Bell 430 helicopter had tried to contact the Air Traffic Control, Chennai, at least twice and had desperately called for guidance,as they had lost their route.
The revelations can put the ATC Chennai in the dock for negligence leading to the fatal crash.
According to sources investigating the crash last Wednesday in which YSR and four others died, the cockpit voice recorder has yielded some vital information about the last few minutes in the helicopter that was caught in turbulent weather while flying over Nallamalla forest in Kurnool district.
The CVR and the flight data recorder were recovered from the crash site atop the Pavuralagutta hillock, about 70 km away from Kurnool.
The probe team, headed by the director general of civil aviation, has sent the CVR to New Delhi for analysis.
Sources said that the pilot had been calling for help in Hindi, however there was no response from ATC Chennai.
The helicopter, which took off at around 8.35 am from Begumpet airport in Hyderabad for Chittoor, had entered the area controlled by the ATC Chennai at 9 am.
It had established contact with ATC Chennai at 9.02 am and had wanted to switch over from ATC Hyderabad to ATC Chennai, however the latter told the helicopter crew to contact them again at 9.30 am.
The recorder shows that the pilot had repeatedly attempted to contact ATC Chennai between 9.22 am and 9.30 am, but there had been no response.
Focus on the last 18 minutes
The CVR analysis will reveal the entire sequence of events -- right from the take-off to the time of the crash and details of what transpired in the cockpit, and between the pilots and the ATC.
However, sources said, the focus was on the last 18 minutes -- the period between the last contact with ATC Chennai and the crash.
They added that YSSR's wristwatch, which was found at the crash site, had stopped exactly at 9.30 am suggesting the exact time the crash might have taken place.
What has puzzled experts is that the communication between the cockpit and the ATC had snapped much before the helicopter had crashed. The DGCA team will investigate to find if there had been a technical failure that led to the break in communication.
Chopper exploded into ball of fire
Meanwhile, preliminary investigations by the crime branch of Andhra Pradesh, the criminal investigation department and forensic experts has revealed that the ill-fated helicopter had dragged on the ground for a distance of 120 m before it hit a tree and exploded into a ball of fire. Investigators have reached this conclusion on the basis of the marks found on the ground, the damaged shrubs and trees, and pieces of helicopter strewn around.
The helicopter, which had fuel sufficient to run for two hours at the time of the crash, had exploded with such intensity that the body parts of the five inhabitants were thrown afar.
The AP investigating team has also said that during the crashlanding, the flying pieces of the chopper had cut through the passengers' bodies, which had later got burnt in the explosion.
No explosives found
Experts also said they did not find any evidence of explosives in the blast and that the helicopter was destroyed as a result of the crash.
M S R K Prasad, head of the forensic department at Kurnool hospital who performed the post-mortems, said two fingers of the right hand of YSR had been found severed.
The post-mortem reports described the cause of the death as deep shock or "haemorrhage shock".
He also said that YSR and others were alive for a few minutes after the crash.
Mobile phone found dead
Investigators have also found three mobile phones believed to be of YSR, his principal secretary P Subhramanyam and chief security officer Wesley. The phones of the two pilots were found shattered. Though the recovered mobiles were dead, experts hope to get some information by accessing their memory card.
The team is also likely to question the staff of ATC Hyderabad and ATC Chennai, as well as the ground staff responsible for maintenance of the helicopter at Begumpet airport. The state government will also take the help of CBI as it involves cross-state investigations.
Teams searching the crash site have also found the much talked about emergency locator transmitter that had failed to activate itself after the crash and relay signals to those looking for the missing helicopter. The Andhra Pradesh Aviation Corporation has said that the Bell Company's engineer had certified that it had been in good condition.
A two-member expert committee constituted by the state to probe other aspects that will look into the circumstances before the take-off and after the crash.
DGCA team to arrive on Wednesday
The DGCA team will reach Kurnool on Wednesday and spend two days in the district to probe the incident. A helipad has been built for the team's arrival at an inaccessible spot in the forest atop a hillock. The team will cover a small distance in a tractor or a jeep and then walk for three km to reach the site.
Image: Pieces of debris of the crashed Bell 430 helicopter in which YSR had travelled
