Thursday, September 29, 2022

Bangalore Survives A Mid-Air Collision, But How Did Boeing 747 Crash Into Il-76 Near New Delhi 25 Years Back?

On January 7, a near-miss incident involving two IndiGo flights was reported at the Bengaluru airport in southern India. The Directorate General of Civil Aviation (DGCA) has now ordered an investigation into the incident.

India has witnessed several mid-air collisions over the past three decades, the deadliest being the 1996 Charkhi Dadri crash.

Disaster Averted In Bengaluru

DGCA chief Arun Kumar said that on January 7, IndiGo flights 6E 455 and 6E 246, which were departing for Kolkata and Bhubaneshwar, respectively, were given permission to take off at the same time.

Bengaluru airport has two runways — the north runway is for takeoffs and the south one for landings. They run parallel to each other. India does not allow simultaneous runway operations for departures at airports.

“On the morning of the incident, the north runway was being used for departures and the south runway was being used for arrivals. Later, the shift in-charge decided to close the south runway but failed to inform the air traffic controller in-charge of the south runway,” a senior DGCA official told the media.

An unnamed source told The Hindu that due to this, at the time of the shift to single runway operations, the Kolkata flight was given permission to take off from the runway that was already declared closed. On the other hand, the flight bound for Bhubaneshwar was also cleared for departure from the other runway.

After taking off, both the airplanes moved in the right direction as per their destination. They came within seconds of colliding with each other. However, a major disaster was averted as an alert radar controller noticed that the paths of the two aircraft were converging and urgently intervened to steer the two aircraft away from each other.

File:Airbus A320-232, IndiGo Airlines JP7701002.jpg - Wikimedia Commons
File Image: Indigo Airlines, India

This incident raises pertinent questions about the lack of coordination among air traffic controllers of the Airports Authority of India (AAI). Additionally, it also highlights the lapses that occurred in reporting the incident to the safety regulator DGCA.

“It was during our surveillance that we came to know about the incident. AAI didn’t report the incident,” the DGCA source revealed.

The DGCA has declared that it will be probing the incident and will dole out stringent punishment to those found guilty.

Past Disasters 

Despite reports of multiple near-miss incidents over the years, it has been revealed that in terms of actual air crashes, the decade from 2011 to 2020 has been the safest period in independent India. The only crash that led to fatalities in this period happened in the August of 2020 in Kozhikode.

Even the decade preceding this — from 2001 to 2010 — was relatively safer with only one fatal accident. This one happened in May 2010 when an Air India Express flight crashed after landing at Mangalore, claiming the lives of 158 of the 166 people on board.

However, the period from 1991 to 2000, was worse. There were seven fatal crashes that led to the loss of 552 lives overall. Most notably, this included the deadliest mid-air collision in the world — the Charkhi Dadri accident which resulted in 349 casualties.

The Charkhi Dadri Crash

The incident happened in November 1996. All passengers and crew on board were killed when a Saudi Arabian jumbo jet, shortly after taking off, collided with a Kazak Airlines plane that was approaching the New Delhi airport.

Saudi Arabian Boeing 747-SP landing & take-off @ GVA - 28/7/2012 - YouTube
File Image: Saudi Arabian Boeing 747

The high death toll made this crash the third-deadliest air crash and the worst mid-air collision in the history of aviation.

Rescue teams, guided in their search by the flames that had erupted due to the accident, initially reported that there were no survivors from the Saudi Arabian Airlines Boeing 747 and the Kazak Airlines Ilyushin 76. The two had collided at 6.40 pm.

At the time, officials at the scene had told the media that villagers in the region had reported ”three or four” survivors in the wreckage immediately after the impact. According to their account, all but one had died before the rescue teams arrived. Though it was stated that the sole survivor was taken to a local hospital, a survey showed later there were no survivors.

The people killed aboard the Saudi plane were mostly Indians; there were 17 foreigners also on board.

Kazak officials had told the media that the Ilyushin, which was arriving from the southern Kazak city of Chimkent, had been chartered by a company in neighboring Kyrgyzstan. Thus, most passengers on board this aircraft were Kyrgyz.

What Caused The Crash

The events before the crash are quite clearly documented. The pilot of the Kazak flight identified himself as KZA-1407, flying at 23,000 feet (FL-230) and descending to 18,000 feet (FL-180).

The control tower instructed the pilot to inform them upon reaching 15,000 feet. Then the Saudi Airlines Boeing-747 (flight SV-763) joined in, making the conversation a trialogue.

This flight had taken off from Delhi with close to 300 passengers for Dhahran and Jeddah. The Saudi pilot informed the tower that he was approaching 10,000 feet (FL-100).

2014 Ukrainian Air Force Il-76 shootdown - Wikipedia
File Image: IL-76

The two aircraft were on the same path, one had taken off and the other was planning to land. This was routine business. The tower told the Saudi plane to climb to FL-140 and instructed the Kazakh pilot to remain at FL-150.

Instructions were quite clear and everything seemed well till 6.40 pm that day when the blips of both the aircraft disappeared from the radar.

There could have been three plausible reasons for the crash, which is believed to have happened at 6.41 pm over the skies of the northern Indian state of Haryana.

It could be that the Kazakh pilot, who heard and acknowledged the instructions, did not obey them in a hurry to reach the ground, or that he didn’t completely understand the instructions due to language barriers and differences in the use of measurements — the Kazakhs at that time used the metric system, while the instructions were in given in feet units.

The other reason could’ve been that the Saudi pilot flouted the instructions, or, did not hear them. Lastly, it could have been that both of them flouted the instructions.

When the judicial investigation report, prepared by Justice R.C. Lahoti, came out, it identified the unauthorized descent of the Kazak to FL-140 as the root and approximate cause of the crash. The reason why this happened was reported to be the language and measurement conversion barriers.

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