Charkhi Dadri midair collision: Horror in the sky

India Today

a day ago

(NOTE: This article was originally published in the India Today issue dated November 30, 1996)Commander Gennady Cherapanov seemed relaxed and in control as he guided the IL-76 into the descent to Delhi over the dusty cotton and mustard fields of western Haryana. In 15 minutes, the chartered flight would be on the tarmac at Delhi's Indira Gandhi International Airport. And in an hour, the 29 Kyrgyzstani shoppers on board could be on Janpath.advertisement"Good evening," the pilot greeted air-traffic control (ATC) as flight KZA 1907-owned by Kazakhstan Airlines but chartered by a group of Kyrgyz-made contact with Delhi, informing the tower that he was coming down from 23,000 ft to 18,000 ft. The controller, V.K. Dutta, who was recently promoted as senior aerodrome officer, knew from his schedules that the aircraft was due to land in Delhi.Dutta cleared the descent to 15,000 ft. Cherapanov confirmed that and cruised along at that height-or so Dutta thought. In the villages surrounding Charkhi Dadri in the heart of Haryana, everything was quiet on the evening of November 12. The last firecrackers of Diwali had been exhausted. Routine was back. It was Tuesday. Many were preparing to adjust their watches to 6:45 p.m., when the scrupulously punctual Saudi Airways flight SVA 763 flew overhead thrice a week. It was on time that evening too.advertisement
On board the Saudi Airways jumbo jet, carrying fitters, mechanics, odd jobbers chasing money and dreams, captain A.L. Shbaly was beginning his ascent. At 10,000 ft he spoke into his radio, letting the ATC Delhi know his height. "Cleared for 14,000," Dutta replied. The 747 continued to climb. At 14,000 ft Shbaly asked the ATC for clearance to go higher. Dutta asked him to stand by for clearance for further ascent. But did he?That is unclear. What is clear is that Cherapanov was told that there was a Boeing coming his way. "Maintain 150, identified traffic 12 o'clock." Dutta warned Cherapanov. What that meant was that the Jumbo was coming straight at the Kazakh plane. Flight SVA 763 was just about 25 km away from the Kazakh aircraft. Dutta also asked him to report if he sighted the Boeing. Even if he did see it, Cherapanov didn't get back to Dutta.As Dutta watched his radar, he saw the two blips converge. He wasn't overly concerned because that could mean one aircraft was just flying over the other. He had seen blips merge and separate on his outdated primary radar in the past. Not this time. To Dutta's horror, the blips converged and disappeared.advertisementHitting on a road in rural Haryana, retired subedar Mahendra Singh saw something far more awesome. "I saw this fireball, like a giant burst of gas on fire," says an awed Singh. Others living around the town of Charkhi Dadri, 80 km northwest of Delhi, saw those flames too. They say they lit up a sky rapidly fading to dusk. They heard a sound fiercer than thunder. It was nothing like they had ever witnessed.In the air, a US aircraft ferrying supplies to the embassy in Delhi spotted two streaks of flame descending rapidly downwards. But even they did not catch the moment. Those who witnessed that fraction of a second, lost somewhere between 6:41 p.m. and 6:42 p.m. on November 12, did not live beyond it.Tonnes of flaming steel hit the ground seconds after the 747 hit the underside of the IL-76. There was evidence in the wreckage to show that the collision wasn't head-on: the windshield of the descending Kazakh aircraft was almost intact.The windshield may have survived, but none of the passengers in either plane could escape annihilation. When two aircraft hurtling at 500 km per hour slam into each other, the passengers and crew don't have much of a chance-the impact is 700 times that of a powerful car crash. In a fraction of a second, the thunderous collision decompressed the cabin and starved passengers of oxygen. Their liver and spleen were smashed to pulp and their hearts burst on slamming against the rib-cage at 500 km per hour. Death followed almost instantaneously-leaving little time to feel pain or realise they were dying.advertisementMore than 500 tonnes of wreckage lay scattered over a 7-km stretch of farmland; 351 bodies-and parts of them littered the fields. The fuselage of the Boeing 747 burned into the night. The mid-air collision revealed gaping holes in India's air-safety systems, gaps that may have caused the third-worst tragedy in aviation history. Indian skies were perilously close to another head-on collision between aircraft just four hours before.INDIATODAY has learnt that in the same area above Delhi a similar collision was averted when the pilots of an AN-32 and an Avro, both Indian Air Force planes, realised after listening to radio communication that they had both been given clearances to approach at almost the same level at the same time. "We avoided the mishap by a hair's breadth," says a crew member of the AN-32.advertisementBut nothing on the transcripts of the last conversations the pilots of the two ill-fated planes had with ATC revealed any problem. "The transcript clearly shows that both the pilots know that they were approaching each other," says Civil Aviation Secretary Yogesh Chandra. "It is not air traffic control's fault."So was Commander Cherapanov really flying at 15,000 ft, the height he confirmed to ATC? With the equipment ATC has at present, there is no way of checking an aircraft's altitude. Says Director General of Civil Aviation H.S. Khola: "We have simply to take the pilot's word for it." Moreover, the altimeter, which gives height readings, could have been faulty in either plane.Officials also say that there may have been a language problem between the crew on the IL-76 and the ATC. The Kazakh crew, they said, were not very conversant in English and could have misunderstood some of the instructions. A Kazakh official scoffs at the suggestion: "How come they understand English everywhere else they go?" The transcript of the communication between the ATC and the Kazakh pilot bear that out.UT while the Government seems bent on giving the airport authorities a clean chit, and pin the blame on the Kazakh pilot (data is being collected on the poor safety record of Kazakh airliners to bolster the case), it is clear that an accident of such magnitude could occur only after a series of lapses.advertisementThe first of these lapses took place when Captain Shbaly was asked to stand by for further instructions if he wanted to continue his ascent. It would be the last time the two would talk. He did not follow the rules; he did not repeat the ATC's instructions in acknowledgement. And the ATC said nothing further. According to aviation norms Dutta should have repeated the instructions and asked Shbaly to acknowledge them. It isn't clear if the 747 continued to gain altitude without clearance. The obsolete primary radars at IGIA's ATC, which show only lateral distance without showing vertical separation, didn't allow the ATC to check.It appears then that some simple obedience of the rule book by both the pilot and the Delhi tower might have avoided the tragedy. It also seems clear that one of the planes did not keep to the level given.The complete picture will emerge only once the flight-data recorders of the two aircraft are decoded. But the black boxes will not tell how outdated equipment could be jeopardising air travel. Air traffic in India isn't going to lessen. The pressure of more flights is already telling on Indian airports. Delhi airport's aging air-traffic infrastructure is supposed to optimally handle 12 flights an hour. But the actual figure is more than 20, posing serious risks (see box). V.K. Chandna, director, air safety, Directorate General of Civil Aviation (DGCA), says the Haryana disaster was "a freak accident, but not totally impossible because of ever-increasing air traffic." It's vital then, to ensure that the margins for error are curtailed.So how do we make the skies a safer place? Bring in new technology; revamp ATCs; install new sensors, both in planes and in airports; and improve pilot training. Control towers must be the first beneficiaries so that they receive sophisticated equipment (standard in many countries) that allows controllers to find out the height of an aircraft. Right now, all that guides controllers are blips on a screen. If two blips overlap, they have no way of knowing how far apart the planes actually are.State-of-the-art equipment from the American electronics company Raytheon is being tested and is scheduled to come on stream in Delhi and Mumbai airports by early 1997, officials claim. "Our anxiety to upgrade it does not imply that the existing ATC system is outdated or inadequate," says Ranjan Chatterjee, chairman of the Airports Authority of India.The ATCs all over the country can't keep pace with technological change in modern aircraft. From June 1, 1996, the DGCA made it compulsory for all commercial aircraft to have a mode C transponder. That means that if there's an obstacle in the flight path, the instrument will alert the pilot. It gives a reading of altitude, which is then transmitted to the ATC.But the transponders are still useless in India because they need special radars that can receive their signals. And no Indian tower can do that. Guwahati, Delhi, Mumbai and Trivandrum were supposed to have these compatible radars by June 1, but they're nowhere in sight. The Saudi 747 had a Mode C transponder but obviously it was useless.So right now, towers in India have no way of knowing a plane's altitude-except taking a pilot's word for it. And how dangerous that can be has become evident. Either of the two pilots-or both-could have got their altitudes wrong over Haryana.T also seems clear that technology change must be used to stop accidents, not used as a knee-jerk reaction after one. It was only after a crash in Ahmedabad on October 19, 1988, that Indian airports got instrument-landing systems. The same thing happened in Imphal. In Aurangabad the airstrip was widened only after a crash.The Government insists safety is a key concern. Two months ago, a committee headed by an air marshal was set up to review current safety standards. "We are observing international standards of air safety," says Civil Aviation Minister C.M. Ibrahim. That is perhaps stretching the truth. But if ATC systems are upgraded, the skies would certainly be safer. For one, the new system would reduce verbal communication between pilots and the tower. Officials admit that a language problem between ATCs and foreign pilots is a problem area; the communication gaps imperil air safety.But there's a major impediment to upgrading ATC systems: money. "Upgrading needs hell of a lot of money," says Khola. "And that is a problem." However, he insists after Delhi and Mumbai, traffic control systems in other airports will be modernised.In the future, civil aviation officials hope to introduce a satellite-based communication and navigational surveillance air-traffic-management system. A ministry project envisages the dismantling of ground-based ATC systems by 2010. But with the failure to quickly replace today's old systems, this seems wishful thinking. And this technological time lag, warns one aviation expert in Delhi, is at the cost of air safety.When that happens, tragedies like the Saudi-Kazakh crash will be difficult to prevent. Whatever the reasons for the crash, it seems clear that a technologically superior tower in Delhi could have warned Commander Cherapanov and Captain Shbaly of impending doom. Safety can no longer be neglected. As one commercial airline pilot, who flies that narrow Hissar-Delhi corridor frequently, says, "If safety is too expensive, try an accident."Subscribe to India Today MagazineMust Watch