Was the first jetliner a failure?
Mr Charles, a pizza store owner in Italy, likes the thrill. When he was 15, he jumped into the sea from a cliff because he wanted to feel how it felt diving into the sea from a cliff. But he didn’t know swimming- Yes, Mr Charles was rash, and this liking for thrill trumped his faculties. Well, Mr Charles survived the jump into the sea as his would-be wife was swimming near the cliff. Now, no one is sure whether he jumped because he was sure that the girl would save him, or his thrill-seeking nature made him jump. But who cares- Mr & Mrs Charles have now shared many thrills.
Aeroplanes had always fascinated Mr Charles. He and his wife have been on aeroplanes powered by propellers. And the propellers had noisy piston engines turning them. Though that was the only kind of aircraft available for passengers at that time, Mr Charles had heard about a British Company coming up with an aircraft powered by jet engines. His thrill side was waiting for a chance to fly on one of these jet-powered aeroplanes.
In 1952, Mr Charle’s wait ended, De Havilland, a British company, handed over its first jet-Comet- to the British Overseas Airways Corporation (BOAC). But for some personal and business reasons, Mr Charles could not board the Comet before January 1954.
He had seen the aircraft pictures in the newspaper, and he couldn’t stop thinking about it. For him, it was the most beautiful machine that man ever made. Finally, on his journey day, at the airport, Mr Charles sees the aircraft on the tarmac, and it was better than what he had imagined. The design was ahead of its time: the aircraft body (fuselage) was bullet-shaped, engines were concealed, and it looked like a perfect flying machine. Alistair Hodgson, curator of the de Havilland Aircraft Museum. “It was clean, it was aerodynamic, and it looked like it would slip through the air perfectly — and of course, that’s what it did.”
The aeroplane took off from the airport in Italy. The cabin wasn’t noisy. It was vibration-free, and the aircraft zipped through the air at speeds up to 460mph, about 100mph more than any passenger aircraft. The jet engine was meant to fly at high speeds and altitude, although the engines were fuel guzzlers.
The experience of sitting inside the Comet was the finest one- First class had tabled with passengers seated around it. As Hodgson remarked- That’s what happens when you allow engineers to design aircraft rather than accountants. Flying in the 1940s-50s wasn’t for the middle class. The airliners knew that their target was the rich crowd who could afford to pay for the frills. “Air travel was just in its final days of being a thing for the rich only.”
The Comet took off from the airport in Italy, but 20 minutes into the flight, the aeroplane ripped apart. No passenger survived. Though it wasn’t the first accident of a comet, the accident’s serious nature led to the grounding of all BOAC and Air France Comets’. The British ministry of civil aviation started the accident investigation. The British Navy had the task to retrieve the debris from the depths of the Mediterranean Sea.
The Navy had retrieved a big section of Yoke Peter’s tail and skin from the fuselage. The wreckage was taken to the Royal Aircraft Establishment at Farnborough, England. The investigators, scientists and engineers concluded that Comet as a plane -design- was safe to fly. As the investigators put it: “there appeared to be no justification for placing special restrictions on the comet aircraft.” The grounded comets once again soared the sky.
Let’s give our imaginary Mr Charles and Mrs Charles another life. Would they still want to board the Comet? Will, Mr Charles is thrill-seeking and daring. He trusts the investigators to have solved the problem. He got on board another Comet in April 1954. Was he right in trusting the investigators or like before the plane disintegrates mid-flight? Well, Mr and Mrs Charles meet the same fate. The Comet came apart midair and again over the Mediterranean. One of the pilots who flew the Comet said after the second crash: “I still do not forgive those who restarted the services after the first crash.”
So, what was happening? Was some mysterious force tearing apart the aircraft or a flaw existed in the Comet’s design that the engineers had overlooked?
The Comet was way ahead of other aircraft. The cabin had to be pressurized because the passengers had to breathe at 35,000ft which was Comet’s cruising altitude. The air inside the aircraft was at a higher pressure than the air outside. But when the aircraft flew at a lower altitude, the inside pressure was decreased. It’s like you are repeatedly inflating and deflating the same balloon. Hodgson said: “If you do that, it’s like taking a toy balloon and blowing it up and deflating it constantly-eventually it’s going to tear.”
This is precisely what the aircraft wreckage recovered from the first crash pointed at-metal fatigue. Due to the repeated expansion and contraction of the fuselage, the aluminium body became weaker and weaker. Eventually, the metal couldn’t bear the repeated stress that it had to go through with each pressurization cycle. Finally, the metal ripped apart on the two ill-fated flights.
To prove this, the investigators immersed the Comet’s fuselage in a large water tank. The fuselage was submerged and filled with water. Further, water was pumped into the cabin until the pressure inside the fuselage was 1P, the same during the flight.
The Comet that was in the water tank had gone through 1230 pressurized flights before testing and 1830 tank flights [i.e., 3060 pressure cycles. After 3060 pressure cycles, a sudden drop in cabin pressure was recorded. The water was drained, and the engineers saw a wide split in the fuselage. One engineer remarked, “it was unthinkable that an aircraft can crack like this. As if an earthquake had split the aircraft wide open along the fault line. The fracture began in the corner of a window atop the aircraft- the split ran eight feet through a window frame. Indeed, the Comet had a design flaw.
The aircraft had two flaws:
1. Building method: To make the aircraft lightweight, the engineers used thin skin on the fuselage. This meant a weaker aircraft outer body.
2. The square-shaped window had sharp corners that put extra stress on the metal around it, especially at higher altitudes- 2 to 3 times more than other places on the aircraft.
Was the Comet a failure? No. It would be anything but a failure. The Comet changed the way humans flew. Pressurized cabin, flying at 500 mph, concealed engine- the design was amazing. The bullet-shaped fuselage that Comet had still held good. Turbojet engines, the Comet embodied innovation at its best. No one denies that its design had flaws and people lost their lives for it. But the Comet was the first of its kind, and the engineers couldn’t precisely comprehend the effect of repeated pressurization on the aircraft. If anything, the second disaster was preventable for the engineers gambled, and people lost lives in the process.
Having said that, the Comet made the future aircrafts much safer-Boeing 707’s. The lessons learnt from the Comet that the future aeroplanes didn’t disintegrate midair. As Richard Gale puts it: The Comet is a reminder of innovation and ingenuity, as well as risk and sacrifice. Its introduction was the start of a revolution in air transport that we can sometimes take for granted, and its mistakes the start of a safety-first culture in aviation that we could not function without.
