CORRIDORS OF DEATH
MID-AIR collisions are rare in the super jet age. They are even more improbable in perfect flying conditions when traffic volume is not high by international standards. Yet on November 12, the improbable happened. A Saudia Boeing-747 bound for Daharan via Jeddah took off at 6.33 pm from Delhi. The flight was cleared by Air Traffic Control (ATC) officer V.K. Dutta, a veteran whose practiced eyes have guided aircraft innumerable times. A minute later he got a call from a Kazakh Air cargo IL-76, coming from Chimkent, seeking descent from 23,000 feet to 18,000 feet—the plane was scheduled to land in Delhi at 6.45 pm. Dutta told him to stay put at 15,000 feet and confirm, which the Kazakh did. But seven minutes later, at 6.40 pm, Dutta’s eyes widened in horror as he saw the dreaded ‘beep’ on his monitor—two lines, notifying the movement of aircraft flying separately, had merged into one tiny blob.
That could mean only one thing. And when, at that same moment, a radio message from a roving US air force plane told him the pilot had just witnessed "a ball of fire", the vague sense of panic gave way to visions of disaster. Dutta gave it a last shot by trying to get in touch with the pilots. The radio was dead. Keeping cool, he called his immediate boss who, in turn, spoke to Ranjan Chatterjee, chairman, Airport Authority of India (AAI). The mayday message was transmitted further up the hierarchy in no time: Chatterjee informed Civil Aviation Secretary Yogesh Chandra, who was immediately on the hotline with Civil Aviation Minister C.M. Ibrahim. The Haryana chief secretary was informed next and a press conference summoned within two hours, after some preliminary details were ascertained.
Hours later, when hordes of reporters and officials descended upon Charkhi Dadri village in Haryana’s Rohtak district, the Saudia aircraft’s debris presented a horrible sight. Of the 312 aboard, there was little left, except scattered limbs, twisted metal and burning flesh. About 10 km of dirt road away, at Maliya village in Bhiwani district, lay the mangled ruins of the Kazakh IL-76. The 39-odd Kazakhs on board couldn’t be identified.
In the plethora of theories and allegations, depending upon who the theorist was, only one thing emerged clearly. The tails of both the planes had been mashed to a pulp. Those near the tailend in both the aircraft were burnt to a cinder, making them unidentifiable. The front portions had been damaged, but not mangled. The eventual outcome, of course, was still instant death.
What caused the crash? The Civil Aviation Ministry was quick to defend the ATC, which monitors and guides all air traffic movement in the country. H.S. Khola, director general of civil aviation (DGCA), asserted that the fault lay with one of the pilots (see inter -view). In a prompt backup action, the ministry released the conversation recorded between the ATC and the two pilots which revealed they were aware of each other’s existence.
Sceptics like former flyer R.P. Jain question the bonafides of the recorded conversation. "We just have the Government version of what happened. No independent body has been privy to the tapes to know whether it has been tampered with or not," he says.
The most popular theory going around is that the pilots had erred and either misunderstood or ignored the ATC’s direction. According to one AAI source, preliminary findings suggest the Kazakh pilot, who was talking to the controller through the navigator, might have miscalculated or misunderstood the flight level. "There have been instances when pilots have mentioned incorrect flight levels," the source says. It’s also not infrequently that pilots make their descent and climb quicker than required to save time. The facts, in this case, can be revealed only by the black boxes.
In the context, the role of the ground equipment becomes crucial. Says Chatterjee, who is responsible for maintaining all airports: "The primary radar systems at Delhi can track down flight movement up to 60 nautical miles. The airport surveillance radars (ASRs), which are an improvement, can monitor up to 200 km. Both of the source says. It’s also not infrequently that pilots make their descent and climb quicker than required to save time. The facts, in this case, can be revealed only by the black boxes.
In the context, the role of the ground equipment becomes crucial. Says Chatterjee, who is responsible for maintaining all airports: "The primary radar systems at Delhi can track down flight movement up to 60 nautical miles. The airport surveillance radars (ASRs), which are an improvement, can monitor up to 200 km. Both of them are of 1972-73 vintage, but provide excellent service." And therein lies the catch. The current radars do not reflect the altitude at which the planes are flying. Thus, while they can determine horizontal space between two aircraft approaching each other, it becomes a problem to determine the vertical distance between them. For this they have to depend on the pilot’s word. And quite obviously, in this case, at least one of the pilots had communicated the wrong height.
This point needs elaboration.
In a newspaper column, former air vice-marshal Narendra Gupta wrote that the ATC is required to give horizontal and vertical differences between aircraft. "Vertical separation was attempted by asking the Boeing-747 to climb to a height of 14,000 feet and the IL-76 to stay at 15,000 feet." What, questions Gupta, did the ATC do to inform the aircraft of their horizontal difference?
The Government says it has invested in a Rs 423-crore monopulse secondary surveillance radar (MSSR). The sophisticated project—US federal aviation authorities are its consultants—was supposed to have been operational by 1995. Ministry officials offer a weak defence for the delay, saying it takes time to calibrate and put adequate software into the machine. After the crash, the issue has gained importance. While Ibrahim says the system should be on stream by March 1997, other officials are at pains to deny a report which alleged the equipment disappeared from the high-security airport premises.
One oft-repeated complaint is that airports lack proper radar surveillance facilities. The equipment at Calcutta’s Dum Dum airport is obsolete and vital instruments are out of order for three to four days a month. There was a close shave as recent as September 19. The ATC lost trace of a US chartered plane—everyone heaved a sigh of relief when it landed. Of the two instrument landing systems, only one functions.
But those who man ATC towers have their own litany of woes. Apart from the fact that they get one-tenth of what pilots earn, they have used the crash to highlight the technical difficulties of their job. Their most nagging worry: crowded air corridors. Says Brijendra Shekhar, general secretary, Air Traffic Controllers’ Guild: "There is only one bi-directional route to and from Delhi. Aircraft arriving or departing have to follow the same narrow corridor. ATCs in Delhi have been making requests for a long time for separate routes. We are told that Vayu Bhavan is not giving more space to commercial aviation." In Delhi, 70 per cent of the skies are controlled by the Air Force and only the remainder is left for the civvies—of course, there is an Air Force liaison movement which keeps in touch with its civilian counterpart but that’s about all.
Does it mean the ATCs are overworked? The ATC is divided into four zones—Delhi, Mumbai, Madras and Calcutta. A total number of 700 personnel have to work round-the-clock, putting in an average 42 hours a week on the job. Compared to this, in the United States or Europe, a man does the same job for just 25 to 30 hours a week. Juxtapose the traffic movement figures, and it makes for interesting reading. At London’s Heathrow airport, 1,100 aircraft either land or take off every day. The total aircraft movement in Delhi and Mumbai do not exceed 300 to 320 flights a day. Some pilots cite the fact that there have been instances when mid-air collisions were averted in the past. Says V.K. Bhalla, regional president, Indian Commercial Pilots Association: "I brought it to the DGCA’s notice last year." He highlights three cases. (See Officially recorded misses)
To be sure, reforms are needed, particularly in the DGCA. A four-member panel headed by Air Marshal J.L. Seth was set up in September to review existing systems. The panel’s report, expected by March 1997, can’t go uninfluenced by that tiny point that appeared on Dutta’s radar screen. The question is, after the din over the crash subsides, will the aviation establishment take the point?