Air Marshal (retired) Trilok Ghadioke saw action in Burma during World War II and in various operations of the Indian Air Force in independent India. During the 1965 war he was the commanding officer of the Chandigarh airbase.

In February 1968 he was tasked to inquire into the mysterious crash of a Russia-made AN-12 aircraft carrying 100 men, including soldiers and crew, in the Greater Himalayas near Rohtang Pass.

The inquiry was inconclusive. The wreckage and bodies were never recovered, until last month when a team of mountaineers chanced upon the body of a soldier.

The army and air force are now conducting a search operation in the glaciated areas above Kullu-Manali at a height of over 16,000ft to recover the bodies and wreckage, including the black box, and thus unravel the last minutes of that fateful flight.

Air Marshal Ghadioke spoke to Josy Joseph about his inquiry and the possible reasons for the crash:

I was director (personnel-officers) at the air headquarters when the AN-12 crash took place. I was detailed by the air headquarters to conduct the inquiry into the mishap. A team of officers -- I and some five or six of us -- assembled in Chandigarh soon after.

The first thing we did was to simulate the entire flight mission and study various factors. I flew an AN-12 assuming it was Flight Lieutenant H K Singh's ill-fated flight. We took off from Chandigarh, with the cargo portion packed with weight equivalent to that of passengers of the crashed flight, and flew over the Greater Himalayas where the plane crashed, and went to Leh and landed there.

After our investigations, we came to the conclusion that some emergency had hit the aircraft in the last moments. Precisely what emergency we were not able to establish.

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But we put our fingers on lack of oxygen in the rear part. The aircraft has two portions -- the front portion, which is the flying deck where the pilots sit, and the rear portion, which is the cargo section where the soldiers, or parajumpers, etc, sit. The rear portion is not pressurised but it has oxygen points. The pilot's flight deck is pressurised.

For the passenger area the oxygen stored is liquefied oxygen, which turns into gaseous state when it is released into the cabin. We don't know if there was 100 per cent oxygen stock, or if it was only 90 per cent.

In our judgement this would be one possibility. Oxygen might have been running out so he wanted to descend to save the passengers. The pilot was safe, because his cabin was pressurised. But the question is why did he not report the situation. If that was done then at least from the Air Movement Control Centre at Udhampur we would have known a little more of the difficulty that he faced.

One crewmember stays with the passengers in the rear portion to provide any assistance that passengers might require. He is in touch with the pilot, constantly telling him about temperature, oxygen level, etc.

It seems that the flight was running out of oxygen because this flight had proceeded beyond the range that had been specified to it. So the oxygen consumption was probably exceeding the limit.

The question was if there was an emergency why was the Air Movement Control Centre in Udhampur not informed of it. He was descending prematurely for whatever reason.

When one is anxious to get down to ensure passengers' safety, it is possible that one is making mistakes about the location. He is much over the Greater Himalayas. But there was no question of landing there. During his descend he crashed into the mountain.

During our investigations we marked an area of probability, I don't remember exactly how much was it. But even if it was a radius of five square kilometres it would be some 100 square kilometres or so. That time it was winter (February) and at 20,000 feet there was several feet of snow.

The Indian Air Force did not have high altitude helicopters then and we also did not have other equipment necessary for conducting such a search. The question now being asked repeatedly is why we did not conduct detailed search. My point is whatever resources we had we utilised them and tried.

Don't forget that this, the non-recovery of bodies and wreckage, is not something unheard of. During World War II when the Americans were carrying out operations from Northeast area, there was a crash. It was some years later that somebody found a skeleton with a holster and a revolver in it. From the number on the revolver the Americans made out the name of the pilot.

Also in 1947 one of our Dakotas that went to Srinagar crashed somewhere in Kashmir. Nobody could locate it. Years later somebody found the wreckage beyond Pehalgam.

Unless you had resources you could not locate wreckage in those days in such remote areas.

If the Air Movement Control Centre at Udhampur had then been integrated with radars then we would have been able to know the exact location of the aircraft. In the absence of such integration, if he was flying in a cloud and was giving incorrect location then you got to take it. If he asks for descend clearance then give him clearance. Because you didn't have resources to tell him that no there is an error in his reading.

I appreciate the concern public is showing for family of those involved in the crash. But I also ask the question, what resources we had? It is difficult to convince people because they think we should have all equipment for all sorts of contingencies.

Now we have helicopters that can fly high altitude; we have integrated radar stations; we can carry out sophisticated surveillance to find out the wreckage. I am sure the dead bodies will be found.