CRASHED PLANES SAVE LIVES
Travelling by air remains the safest way to go. Why? Because every disaster showed us how to stop it happening again.
Just a few decades ago, plane crashes were common, and killed thousands of people. But after each crash, the causes were carefully analysed to improve safety. The next step is a new system that prevents planes from disappearing.
1956 HEAVEN IS A LAWLESS PLACE
41-year-old plane captain Jack Gandy is heading directly into the last storm of his life. With 64 passengers and six crew members aboard, his Trans World Airlines plane took off from the airport in Los Angeles at 9.01 AM, and apart from a delay of about 30 minutes before take-off, Saturday 30 June 1956 seems to be just another day at the office in the Lockheed Super Constellation cockpit.
On its way to Kansas City, Missouri, the plane will fly over the Grand Canyon, and the experienced pilot has taken the trip more than 170 times before. But this morning, dark thunder clouds begin to develop above the sunny Californian landscape immediately following take-off. So over the radio, Grady routinely requests the control tower's permission to climb higher than the instructed cruising altitude of 5,800 metres, allowing him to avoid the intense turbulence caused by the thunderstorm.
Gandy gets his permission, and as he makes his craft climb, he leaves the city of Los Angeles behind, heading into unmonitored airspace. In 1956, planes are only guided and monitored by control towers in the busy airspace above airports. Otherwise, just about all the sky over the US is no man’s land, where pilots are completely left to themselves. No radar keeps an eye on them, and no control tower monitors their whereabouts.
After 1.5 hours of quiet flight, the Trans World Airlines plane is over the Grand Canyon in Arizona, cruising at an altitude of 6,400 m. A few kilometres away, United Airlines Flight 718 with 58 people aboard is on its way towards Chicago, Illinois. The Douglas DC-7, which took off from the airport in Los Angeles only three minutes after Grady’s flight, is flown by Captain Robert Shirley, who is cruising at an altitude of 6,400 metres, as instructed.
In the cockpits of both aircraft, the pilots are focused on navigating through the dense clouds. The visibility is very poor, and Gandy and Shirley stand no chance of spotting each other’s planes, which are heading towards each other at a speed of more than 500 km/h.
At 10:31, radio operators in Salt Lake City, Utah, pick up a vague message from the United plane.
“Salt Lake, United 718 … Ohhh, we're crashing,” says co-pilot Robert Harm. In the background, the radio operators can hear a
“Salt Lake, United 718 ... Ohhh, we're crashing,” is the last radio message from the co-pilot of the DC-7 over the Grand Canyon. LOST FLIGHTS ARCHIVE
high-pitched voice. “Pull up! Pull up,” Captain Shirley orders.
But it's too late. At an angle of 25 degrees, his plane has collided with the Trans World Airlines craft, and the two flights fall almost vertically to the ground like wing-shot birds. Smoking pieces of wreckage are spread across a huge area of the Grand Canyon, and when the rescue team reaches the disaster site, the scenario is a gloomy one. All 128 passengers and crew members of the two planes have been killed, and not one single body is found in one piece.
INVESTIGATOR INVENTS BLACK BOX
The mid-air collision is not by any means the first one in aviation history. In 1950-1955, 65 planes collided over American soil. But the Grand Canyon collision is the by far most deadly, and in the weeks and months that follow, the American people is outraged. Every day, there are newspaper reports about the primitive flight control service, which has not at all moved with the times, about the rapidly rising number of airliners, and the state of complete anarchy in the skies.
“Did Outdated System Kill 128?”, the Detroit Free Press newspaper rhetorically asks in the wake of the disaster.
The public and politicians demand a thorough modernization of air traffic control, and the request is heard. As a direct consequence of the collision, the US government headed by President Eisenhower in 1958 establishes the first modern aviation authority, the Federal Aviation Agency, now the Federal Aviation Administration, FAA.
The organization, which will in the future become a model for the aviation of other nations, is given the task of regulating all aspects of civil and military aviation in the US. The FAA is assigned responsibility for establishing an air traffic control service, which guides, layers, and tracks down all planes throughout American air-space. In other words, the service is to handle all flights, right from the moment the planes are ready for take-off until they have landed again.
In the case of the accident above the Grand Canyon, there is no doubt about the cause of the disaster, but that is a rare example. Crashes are common in the era, and once tragedy has struck, crash investigators often only have a wreckage heap to search, when they are to find out what went wrong.
But already in the 1950s, Australian scientist David Warren thought of something that would revolutionise aviation over time, improving air safety considerably. Warren participated in the investigations of a number of inexplicable crashes involving the world’s first jet airliner, the British De Havilland Comet, which was entered into regular service in May 1952.
After a thorough investigation, investigators established that the disasters were caused by metal fatigue, and the primary culprit was the plane’s rectangular windows. When the cabin was pressurised, the pressure on the corners of the windows was so intense that the metal cracked. The discovery meant goodbye to rectangular plane windows and hello to rounded ones.
“Damn, the son of a bitch is heading right towards us,” says Captajn Grubbs, as the KLM Jumbo emerges from the fog.
David Warren was convinced that the investigative work would have been very much easier, if he and his colleagues had had access to sound recordings of the pilots’ conversation, before things went wrong. If so, it would have been possible to accurately reconstruct what happened before the accidents, said Warren, who in 1954 wrote a report about his voice recorder. Three years later, he developed a prototype of the device, which is now known as the black box and is standard equipment in all major commercial aircraft.
Today, there is not just one, but two black boxes on the planes. Whereas the first one, the cockpit voice recorder, records all conversation and sounds in the cockpit, the second one, the flight data recorder, stores information about cruising altitude, course, speed, etc.
To crash investigators, the black boxes are invaluable tools, which mean that they have been able to solve lots of different aviation crash mysteries. The knowledge with which the boxes have provided experts has meant that aircraft makers have continuously been able to correct errors for the benefit of safety. But when it comes to the most frequent cause of crashes – the human factor – technical improvements are no help. About 3 in 4 crashes are caused by errors made by pilots or air traffic controllers – and that percentage is likely to climb.
As for the cost in human lives, the worst day in aviation history tells the story about how bad things can go. 1977 IMPATIENCE BECOMES FATAL In the afternoon of Sunday 27 March, two Boeing 747s are waiting for permission to take off from the Los Rodeos Airport on the Spanish island of Tenerife. In the cockpit of the one Jumbo from Dutch KLM, Captain Jacob van Zanten is happy, when the control tower finally allows him to take off at 4:30 PM. Due to a bomb in the airport of the neighbouring island of Gran Canaria, all planes have been re-directed to the airport of Tenerife, which is densely crowded. Now, Amsterdam is finally waiting ahead, and in dense fog, van Zanten makes his plane taxi to the end of the runway, where it is to make a 180 degree turn and take off in the opposite direction.
Somewhere behind him on the same runway, another Jumbo from American Pan Am is taxiing. Captain Victor Grubbs has been told by air traffic controllers to get off the runway and wait until the KLM flight has taken off. But in the fog, he cannot find his stop, so he does not move his plane out of the way.
At the end of the runway, Captain van Zanten is ready for
take-off. He is impatient, and consequently, he does not wait for permission from the air traffic controllers to take off, rather he chooses to accelerate his aircraft at full throttle. “We are taking off,” he says over the radio. “Okay. Standby for takeoff. We will be back,” the control tower answers.
“We are still taxiing down the runway,” the captain of the Pam Am flight warns, but Captain van Zanten does not get his message. His huge steel bird is already roaring down the runway at a speed of 260 km/h, and only too late, he spots the Pan Am Jumbo ahead of him.
“Oh shit,” van Zanten says, realizing that a collision is inevitable. He tries to climb sharply, as the Pan Am pilots struggle to get off the runway.
“Damn, the son of a bitch is heading right towards us,” Captain Grubbs says, as the KLM flight appears from the dense fog.
“Get off, get off,” his co-pilot, Robert Bragg, shouts, desperately hoping their own plane will clear the runway in time.
But the fates of the planes are sealed. As the KLM Jumbo takes off, its undercarriage and engines cut through the Pan Am plane’s roof, and the Dutch plane only flies 200 m, before it falls to the ground, exploding in a sea of fire. All 248 passengers and crew members are killed.
The Pan Am plane catches fire, and only 61 of the 396 people aboard it survive. With a total of 583 casualties, the disaster is the worst in aviation history.
“OKAY” IS NO LONGER ON THE LIST
After the tragedy, an army of Spanish, American, and Dutch experts struggled to shed light on the full cause of the disaster. The conclusion is that it was primarily due to the fact that the impatient Captain van Zanten had taken off without permission. The poor vision of less than 300 metres contributed, but the triggering factor was several fatal communication misunderstandings between the Dutch captain and the control tower. Van Zanten considered the air traffic controller’s “okay” as confirmation that the plane could take off. But really, the air traffic controller only acknowledged that he had received the message.
The Tenerife disaster made it clear that air traffic needed a standard language. As a direct consequence of the accident, aviation authorities throughout the world introduced a series of standard expressions that are now used in all communication between air traffic controllers and pilots. The world “okay” is not on the list.
In order to reduce the risk of communication errors and misunderstandings even more, both parties must speak an oddly stilted formal language. When the air traffic controller says something over the radio, the pilot is to repeat the message to confirm that he has understood the words.
The recordings from the black boxes allowed investigators to establish the course of events leading up to the collision in Tenerife in details – right up until the cry of horror that was the last to be heard in the cockpit of the KLM plane.
Air traffic exploded in the 1950s. In the photo, passengers in Los Angeles board a plane of the type that collided with another one in 1956.
583 people die, when two Boeing 747s collide at the airport in Tenerife. The worst accident in aviation history was due to a human error.