Charkhi Dadri collision occurred in "heavy clouds": US pilot
The commander of a US air force aircraft, the only witness to the last year's mid-air collision between a Kazakh aircraft with a Saudi Arabian one over Charkhi Dadri in Haryana, said the accident took place in cumulus clouds which are capable of causing severe turbulence.
In an affidavit, filed in Germany on November 15, just three days after the collision and later submitted before the Justice R C Lahoti court of inquiry, Captain Timothy J Palace, an aircraft commander with the United States air force, said there were heavy clouds 20-30 miles in length in a line approximately parallel to the path of the collision.
The Justice Lahoti court of inquiry is probing the causes and circumstances leading to the November 12 collision between the Kazakh IL-76 and the Saudi Boeing which killed all 349 passengers and crew members on board the two aircraft.
Captain Palace's affidavit assumes significance since arguments of the various parties were based on the possibility and effect of turbulence on the Kazakh aircraft. Kazakh officials claimed the aircraft lost 1000 ft due to severe turbulence.
The US pilot in his affidavit said the clouds were approximately 5,000 ft from base to top.
Captain Palace said his aircraft, which was flying from Islamabad to New Delhi, was descending towards the Delhi terminal area around 15 minutes prior to the collision.
He stated that the air traffic controller at the Indira Gandhi international airport was 'fairly busy' and asked for updated position reports frequently. ''The communications were fairly difficult,'' he added.
It took at least three exchanges to understand one command, he stated.
''We were in the clear when a cloud to our two o'clock position lit up. The light was orange in colour and its intensity continued to increase. We were somewhere between flight level 12,000 ft and 14,000 ft (estimate). The cloud, from what I saw as it lit up, was about 20-40 miles from us, about 20-30 miles in length in a line about even with or slightly below our altitude,'' he said.
''As the cloud lit up, I remarked that it must be a rocket launch. The intensity continued to increase and involve the entire cloud. Then plume of fire came out of the cloud on the right, followed shortly after by one on the left, '' Captain Palace said.
''The direction of movement was hard to determine and we were trying to identify what we were witnessing. I remarked, 'That's not a missile, is it?' I think this was just prior to or about the same time the second plume appeared,'' he said.
"Captain Marks was flying in the right seat and started to bank the aircraft to the left. After a short while (about ten seconds), it became evident the plumes were descending to the ground," the US pilot said.
He said, ''Finally, the glow of the cloud diminished, and the two plumes reached the ground, continuing to burn as two distinct fires. That's when we realised that it might have been a mid-air collision."
''Captain Incerpi was working the radius from the left seat and he informed the controller of what we had just witnessed. The controller made several attempts to contact the two aircraft with no replies,'' Captain Palace said in his affidavit.
Similar affidavits were also filed by other crew members of the US aircraft.
The Kazakh government and Kazakh airlines had submitted before Justice Lahoti that the IL-76 aircraft was made to descend to the flight level 14,000 ft not because of any fault in the aircraft or the negligence of the cockpit crew but due to severe turbulence faced by it in the cumulus clouds.
The Airports Authority of India, the Directorate General of Civil Aviation, the Air Traffic Controllers Guild, Boeing and also the Saudi Airways refuted this view.
These parties submitted that there was no possibility of any turbulence as there was no bad weather on that day and that the crew of the Kazakh aircraft had not been alert to see the Saudi Boeing coming up. They had also accused the Kazakh pilots of not adhering to the ATC directives to maintain the flight level 15,000 feet, besides severe faults in the aircraft.
The AAI and the DGCA both had stated that the Kazakh pilots failed to understand the repeated instructions of the ATC and the Delhi approach regarding the approaching Saudi aircraft on collision path because of their poor knowledge of English.
Kazakh officials pointed out that the Aircraft Accidents Investigation Board report regarding the collision clearly mentioned that ''both aircraft faced increased turbulence levels just before the collision.'' Besides, the IL-76 readings also revealed the bouncing of the aircraft during the turbulence, they said.
They said the ATC had also given information regarding the presence of the Saudi aircraft 'very late', just 38 seconds prior to the collision.
Because of the bad weather and the failure of the ATC to inform them on time about the presence of the Saudi Jumbo, the Kazakh aircraft could not regain its altitude on time, counsel for the two parties submitted.
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