A COMMERCIAL airliner bound for Los Angeles rose from the runway at Chicago’s O’Hare Airport. About 500 feet off the ground it lost one engine on its left wing, rolled to the left, plunged into the ground, killing all 272 persons on board.
On investigation it was found that the engine fell off due to a faulty maintenance procedure that was used to save time when it was removed and replaced after an overhaul.
Such air disasters as this renew the fears some have as to how safe air travel really is. To alleviate some of those fears, we took a look behind the scenes of an average international airline to see just how much attention airline companies give to the safe transport of you, the passenger, to your destination.
Most air travelers are aware that each time a plane lands, specialist teams descend upon it for what is called a transit check. Within two hours a Jumbo can be completely serviced. However, if the stopover is more than four hours, it is towed to the jet base where more extensive maintenance is performed.
While some aircraft may look a little old, every three or four months in the life of the plane, or after 1,400 flying hours, each jet is “hospitalized” to undergo a major maintenance check. Then every five years, or about every 20,000 flying hours, there is a complete refit of the airframe and its engines. What results is virtually a new aircraft internally.
The expert attention given to service a jet engine that operates with a 50,000-pound (23,000-kg) thrust is even more delicate than that given a fine watch by a watchmaker. The engines are meticulously cleaned before being exhaustively examined with microscopes, X-ray equipment, fluorescent penetration equipment and magnetic particle inspectors to detect flaws and cracks too minute for the human eye ever to see.
The extreme accuracy sought and obtained is reflected in the engineering shop where machines work to a tolerance of one millionth of an inch. The thickness of this page that you are reading is more than 3,000 times that measurement, a hefty three thousandths of an inch thick!
The gyros that guide the aircraft are tested so accurately that their rate of drift is less than 0.1 of a degree per hour. This means that after a ten-hour flight (Sydney to Honolulu) without any checks or outside help from any other guidance system during the flight, the aircraft would be, at most, only 7 miles (11 km) off target, after flying a distance of 5,000 miles (8,000 km). Yet there is not just one guidance system operating but two others as a backup in case one should fail.
The high performance demanded of the sensitive navigation systems could be impaired by the slightest dust contamination while being serviced. As a guarantee against such contamination, the workshop at the jet base has been quite appropriately dubbed the “clean room.” Its standard of cleanliness would be the envy of every housewife or hospital surgery.
The staff are scrubbed clean before entering, and are fitted with special clothing that covers even their hair and feet. The chance of impurities entering when the entry door is opened is minimized by having the staff step into the room at the downstream end of a gentle flow of air moving at about 1.2 miles (2 km) per hour.
Electronic equipment filters every pocket of air and permits no more than three and one half contaminating airborne particles, down to 0.5 of a micron in size, in each liter of air (a hair from your head is a chubby 100 microns thick). A supersensitive machine monitors the amount of airborne contamination in the “clean room.” Ideal conditions give a zero readout on the digital display.
When the workshop first acquired the machine, technicians were a little doubtful that it was working properly because it showed a constant zero or near zero readout. In a simple test, they took it outside the “clean room” environment into an adjacent corridor. The counter jumped to hundreds of thousands within seconds, illustrating just how clean their room really was.
Spawned from space-age technology, computers have been drafted into airline safety and service. A computer memory lists all identification cards that jet-base staff are required to produce to gain entry to the base. Entrance is denied to anyone trying to use a card reported as missing.
Rosters for airline crews are also computer controlled to make sure that the pilots are experienced. The pilots especially are subjected to its scrutinizing eye. They must have recent experience in flying the required route, have had a night landing every 90 days, an instrument landing every 45 days, and they must meet many other requirements before they will be allowed to fly the aircraft.
Your safety has also been enhanced by automatic flight planning, also done by computers. The aircraft will be flown over the shortest possible route—yet around bad weather—so as to burn minimum fuel. On just one sector of flight alone, from Sydney to Singapore, up to three tons of fuel can be saved by automatic computer flight planning.
There is more behind the captain’s confident voice than most passengers realize. Because the flight crew of pilots and flight engineers have faultless performances demanded of them, their skill, condition of health and proficiency are constantly examined throughout their flying career.
The training of aircrews has taken a giant step forward with the introduction (and constant updating) of flight simulators. These are identical to the actual aircraft cockpit with all its avionic and electronic control systems. Every moment, and movement in some cases, of a jet plane in flight can be reproduced in such simulators, though they never get off the ground. The pilot hears the engine noise, the cabin noises, feels the bumps in the runway as he taxis along, sees the runway disappearing beneath him as he takes off with trees and airport buildings flashing past, and flies through more varied weather patterns in the simulator flight than he is normally likely to meet. He is also trained to identify airports and their surroundings by night presentation through the simulator, and to make night landings. On board is an instructor who, with a computer, can create any one of 350 emergency situations—from systems failures to extreme weather conditions—even subjecting the flight crew to multiple emergencies. Thus the flight crew receive training over and above the call of normalcy before progressing to the real thing.
The cabin crew of stewards and hostesses are likewise trained to handle all that they are likely to meet in a day’s work and are rigidly schooled and examined in emergency situations. In a mock-up of a Boeing 747 Jumbo, which never leaves the ground, cabin crews are intensively instructed in matters that range from mixing a cocktail to midwifery, how to evacuate over 400 passengers in less than 90 seconds using only half of the aircraft’s ten emergency exits, and how to ditch at sea.
Time and the Unforeseen
The Bible reminds us, at Ecclesiastes 9:11, that, despite all the skill and preparation, “time and unforeseen occurrence befall them all.” Hence, matters outside the programmed technical field affect the safety of air travel. Fatigue, heart attacks and mere errors of judgment have all taken their toll.
Runway lights attract insects and spiders, which in turn attract birds. Incidents involving aircraft striking birds have cost millions of dollars in damage along with loss of human life.
Since increased security was ordered in 1973, more than 2,500 million passengers and 4,000 million pieces of carry-on luggage have passed through U.S. airport security systems. More than 19,000 firearms were detected in that time, resulting in over 7,000 arrests. In only one case, in 1979, did a hijacker smuggle a firearm onto an aircraft. In all other attempts, the hijacker only claimed to have a weapon.
Man’s ambition to fly a heavier-than-air machine with success and safety has achieved a remarkable measure of success. Knowing a little more of what goes on behind the scenes to ensure our safety certainly causes us to breathe more easily. Our flight is the safest that 20th-century technology can generate.