It is learnt that the probe team led by Air Marshal Manavendra Singh examined all likely scenarios for the crash including possible human error or whether it was a case of disorientation by the crew when the helicopter was preparing for landing.
While the first chopper was controlled by Wing Commander Baldev Singh Bisht, the second was commanded by Wing Commander Nikhil Mehrotra.
The inquiry teams had started their work on the very next day the incident took place. The statements are being recorded and in one or two cases, some people have changed their account of the incidents, they said.
The black box, comprising the flight data recorder (FDR) and the cockpit voice recorder (CVR), of the ill-fated Mi-17V5 helicopter of the Indian Air Force was recovered from the crash site on Thursday.
The advanced light helicopter, carrying Army personnel, was on regular sorties, he said. The incident took place at 10.43 am, and search operation is underway, the official said.
Sources said Singh has briefed Prime Minister Narendra Modi about the crash and the Indian Air Force chief has been asked to reach the site.
Out of the 13 people killed in the IAF helicopter crash near Coonoor on Wednesday, the mortal remains of only Chief of Defence Staff Gen Bipin Rawat, his wife Madhulika Rawat and Brig LS Lidder could be identified, officials said on Thursday.
When the IAF veterans' bail petition came up for hearing, in an unprecedented move, senior serving and retired Air Marshals and Air Vice Marshals rallied behind the accused officers and appeared before the court to give sureties for each, something that has never happened ever before.
Here's what to expect at this year's Independence Day in different parts of the country.
The capability of operating fighter aircraft from this area would strengthen the air force's ability to tackle any misadventures by the adversary in a faster way.
Watch the stunning cockpit views of the jets.
The Agniveer passing out parade was as much about family celebration as it was a military event. Alongside the pomp, pageantry and discipline of the parade were the personal stories of families, their struggles and how far they had come.
Over 200 people and two Indian Air Force helicopters were pressed into service to control a wildfire spread over 10 sq km of the Sariska Tiger Reserve in Rajasthan's Alwar, officials said on Tuesday.
Chief of Defence Staff Gen Bipin Rawat was laid to rest with a 17-gun salute and full military honours on Friday.
The person had on Facebook posted derogatory comments about Rawat and the crash and also linked Prime Minister Narendra Modi to it, which went viral, police said.
The defence ministry in an official statement has informed that the minister will give a statement in Rajya Sabha at 11.30 am and in Lok Sabha at 12.15 pm.
Helicopter pilot Squadron Leader Sindhu Reddy will lead the IAF's 144-member all male marching contingent at Thursday's Republic Day Parade.
'Me and my boys had never ever thought in our wildest dreams that we would be taking part in a rescue mission of this kind.' IAF Veteran Air Commodore Nitin Sathe, a helicopter pilot himself, reports on how the air force rescued those trapped in the Deoghar cable cars disaster last fortnight.
The mortal remains were brought to the Madras Regimental Centre where people paid floral tribute to General Rawat and other personnel.
Official sources said the black box was retrieved in the wake of authorities expanding the search area from 300 metres to 1 km from the accident spot.
Chief of Defence Staff Gen Bipin Rawat, his wife Madhulika Rawat and 11 others were killed when an Indian Air Force helicopter carrying them crashed on Wednesday near Coonoor in Tamil Nadu in apparently foggy conditions, killing 13 people on board, the IAF and other officials said.
The QRSAM system is unique in its ability to operate on the move, searching for and tracking enemy targets; and then fire on a short halt.
To ensure the morale of the pilots does not suffer, flying activity continues without a pause. Pilots take to the sky like they would on any other day.
President Droupadi Murmu will lead the nation in celebrating the Republic Day, and Egypt's President Abdel Fattah al-Sisi will be the chief guest at the ceremonial event.
The state officials tried to rescue him on Sunday night, however, they could not get him out.
Condemning irresponsible social media posts and rejoicing over the demise of Chief of Defence Staff General Bipin Rawat in a military chopper crash, Karnataka Chief Minister Basavaraj Bommai on Friday said he has asked the police to identify and initiate legal action against them.
Official sources said Singh will brief President Kovind about the accident as well as the situation arising out of it.
At least 15,000 pilgrims, who were stranded near the Amarnath holy cave in Jammu and Kashmir due to a flash flood triggered by a cloudburst, have been shifted to the lower base camp of Panjtarni, an Indo-Tibetan Border Police (ITBP) spokesperson said on Saturday.
Prime Minister Narendra Modi will unfurl the national flag from the ramparts of the Red Fort on Sunday to celebrate the country's 75th Independence Day and two Mi-17 1V helicopters of the Indian Air Force (IAF) will shower flower petals at the venue for the first time ever.
The fighter jet conducted Eklavya formation by flying at a height of around 300 meter along with two Jagaur and two MIG-29 aircraft. The five jets resembled a V shape with Rafale leading the pack.
Y Joe Alias Kutty on Wednesday recorded video of the helicopter, apparently moments before it crashed.
The newly-inducted aircraft will carry out the 'Vertical Charlie' formation.
Group Captain Varun Singh, the lone survivor in the horrifying chopper crash near Coonoor in Tamil Nadu, was conferred with the Shaurya Chakra in August for averting a possible mid-air accident after his Tejas light combat aircraft suffered a major technical glitch last year.
Several politicians, including senior ministers, wished for the well-being and safety of Rawat and others on board.
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Rajnath arrived in Leh on Friday on a day-long visit to carry out a comprehensive review of the security scenario in the region in wake of the border row with China.
He was the lone survivor of the crash in which Chief of Defence Staff Gen Bipin Rawat, his wife Madhulika and 11 armed forces personnel were killed.
Singh's last rites will be conducted at the Mahatma Gandhi Government School ground in his Ghardana Khurd village and thousands are expected to gather to bid him farewell.
IAF Group Captain Varun Singh, the lone survivor in the helicopter crash that killed Chief of Defence Staff Gen Bipin Rawat and 12 others, is being shifted to Bengaluru from the Army hospital at Wellington in Tamil Nadu, his father said on Thursday.
The Republic Day parade, which will begin at around 1030 am, will be a unique mix of the country's military prowess and cultural diversity, depicting the country's growing indigenous capabilities, Nari Shakti and emergence of a 'New India'.