A Boeing 757 tyre exploded on August 27, killing two mechanics at Atlanta International Airport. It seems like a freak accident today, but back in the 1970s Mumbai and Delhi reported similar fatal tyre explosions
Spend enough time on the road and you’ll hear a tyre burst. Bicycle blowouts sound like a piercing whistle; car tyres almost like a bomb going off. If a bus bursts a tyre while passing you, you’ll definitely feel some whiplash. Aeroplane tyres?
Plane tyres are like dynamite sticks. A recent Quartz report cites research from 1996 that found: “The energy released by a tyre burst can be equated to dynamite.” If it’s a big enough plane, like the US Air Force’s B-52 bomber (only half as heavy as the Airbus A380) one tyre’s explosion is equivalent to two sticks of dynamite.
In the safety of a lab, the results can be spectacular: “Wood framing around a window air conditioner, approximately 240 feet away, was knocked off and a clock fell off the wall,” the researchers found. But in real life, plane tyre explosions can be very ugly.
On August 27, the tyre of a Delta Air Lines Boeing 757 burst during routine maintenance at Atlanta International Airport, killing 58-year-old mechanic Mirko Marweg and his 37-year-old colleague Luis Aldarondo. Another man was critically injured.
Of course, such tyre blowouts in hangars are extremely rare. Which is why the Atlanta news travelled around the world. But back in the 1970s, India reported two such tyre accidents in a matter of four months.
A lesson from Mumbai
On November 14, 1970, Trimbak Anant Gogte, Air India’s senior aircraft technician at Mumbai’s Santa Cruz airport, was replacing one of the front (nose) tyres of a Boeing 707 named ‘Dhaulagiri’ that had arrived from Kolkata. The 35-year-old made the mistake of filling air into the tyre from the wrong high-pressure tank. So high was the pressure that the steel drum of the nose wheel fractured.
The resulting explosion threw pieces of the drum to a distance of “180 to 270 metres,” The Times of India reported on November 15. Gogte was killed instantly, “parts of his person blown off”. The right leg of his colleague NV Tipnis, who was nearby, was also blown off.
What went wrong?
An inquiry was ordered to find out the causes of the ghastly accident, and suggest remedies. On March 27, 1971, Dr Sarojini Mahishi, who was deputy minister for tourism and civil aviation at the time, told Rajya Sabha that in the Mumbai accident technicians had tried to inflate the tyre from a tank containing air pressurised to 3,000 pounds per square inch (psi), instead of using the inflator tank pressurised to only 150psi.
To understand ‘3,000 psi’, take a 1-rupee coin from 2010 (its diameter is 1 inch) and draw a square around it. Now, imagine putting the entire weight of a Tata Nexon on this tiny area. That’s approximately 3,000psi. Car tyres ordinarily contain air at a mere 35psi.
But why did the hangar have a 3,000psi tank? The minister explained that both types of tanks were brought to a plane in a service cart, one for filling tyres and the other (3,000psi) for charging plane “shock absorbers, etc”.
To avoid such accidents, aircraft technicians across India were told on December 30, 1970 never to use the 3,000psi tank for filling tyres. They were to use the 150psi tank that was fitted with a regulator, and monitor the inflation pressure constantly.
Bigger tragedy in Delhi
Less than three months after the government advisory to technicians, another fatal tyre burst occurred at Delhi’s Palam airport.
On March 25, 1971, three men were inflating a spare tyre for an Indian Airlines Boeing 737 at Palam’s hangar number 4. One of them was Indian Airlines’ chief engineer H E Braganza, who had missed witnessing the Mumbai mishap by a month when he was transferred to Delhi in October 1970.
Ordinarily, Braganza would not have done this job, but due to an ongoing lockout in the company most of the technical staff wasn’t available. The airline was flying only Delhi-Mumbai and Delhi-Chennai.
The 53-year-old Braganza, who had returned from a visit to Boeing’s Seattle office just a week earlier, made the same mistake as Gogte in Mumbai. He connected the tyre to the 3,000psi tank. Chowkidar Buddhi Singh operated the tank’s valve while technical officer JC Gupta watched.
The tyre exploded. It flew to a distance of 30m, hitting Braganza and Gupta on the way. “Mr Braganza, whose legs had been blown off after the flying tyre hit his stomach, was declared dead on the spot,” The Times of India reported on March 26, 1971.
Gupta was declared dead on arrival at Willingdon Hospital (now Ram Manohar Lohia Hospital). Singh succumbed to his injuries a day after the news was published, on March 27.
Another inquiry follows
Had Braganza failed to distinguish between the two types of air tanks? The minister said it was unlikely because he had done “floor duties” for 14 years, from 1953 to 1967. Besides, Gupta had inflated Boeing 737 tyres many times.
Also, that morning the airline’s aeronautical officer in charge ‘Vartak’ and director of air safety ‘Prasad’ had alerted Braganza and Gupta to the danger of using the high pressure tank, the minister told Rajya Sabha.
“I learned that the officers on the morning round gave a caution to these people also, that they were using directly from the high-pressure cylinder and that they should not do that. But that may be due to the overconfidence of the technical officer and the chief engineer…” she said.
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