Case of Missing Jetliner Shows Technology's Limits
Monday, June 1, 2009; 4:46 PM
Air travelers are trained to think that planes are stuffed with the latest high-tech aviation gear. But the case of missing Air France Flight 447 is demonstrating technology's limits.
From details known so far, Air France jet carrying 228 people from Rio de Janeiro to Paris had its last contact with Brazil air traffic control Sunday about 4:15 a.m. (10:15 p.m. EDT). The plane entered a zone of storms and high turbulence about 4 a.m., leading to speculation that the jet, an Airbus A330-200, might have been hit by lightning.
Early today, French aviation authorities were officially listing the plane as missing. At the same time, Brazilian and French military planes were combing both sides of the Atlantic Ocean for remains of the plane.
Analysts were scrambling to figure out exactly what kind of satellite-enabled communication systems the plane was equipped with. Using the latest gear, airplanes can automatically transmit information such as the plane's position, altitude, heading and speed. But not all airplanes flying across oceans are equipped with such technology.
Some experts say that given the vastness of the ocean, the crash site might never be pinpointed.
"If an airplane went down in the mid-Atlantic, it could be very difficult to find any physical wreckage," said John Hansman, a professor of aeronautics and astronautics at the Massachusetts Institute of Technology. "The mid-oceans are one of the remotest parts of the world. It's like going to the North Pole. It's in an area of where there is very limited ability to communicate."
That could prove a major headache for safety investigators who place a high priority on finding the plane's black box data and voice recorders. Typically, the black boxes have tracking beacons that activate when the boxes get wet. The radio signal works for about 30 days. Search teams will have to be within 4,000 to 5,000 feet of the black box location to pick up the signals.
Investigators from around the world will want to know precisely what went wrong on the flight. The A330-200 is a common jet in the industry. It specializes in international flying, especially transatlantic routes. Analysts say A330 planes have had an unquestioned safety record. Northwest, which recently merged with Delta Air Lines, has 11 A330-200 planes and 21 of the larger A330-300 models. US Airways has nine A330-300s, according to Airbus.
Hans Weber, an aviation technology consultant, said airplane satellite systems have their limits. "Once the plane hits the water it breaks up," he said. "Just like your car, you may have all this information but if you had a catastrophic accident, the GPS system will not survive.
Aviation authorities use ground-based radar to track planes. But radar can only look out about 100 miles or so, once the plane leaves land. Once out of sight, in the mid-ocean, pilots typically report their positions using high-frequency radio at certain reporting points along the route. Planes have been flying this way over oceans since the 1940s.
High-frequency radio use for air travel over the oceans is described as unreliable compared with overland radio, which allows a pilot to quickly pick up the radio and talk to a controller.
"When you're over the ocean, you are really much more on your own," Hansman said.
The satellite technology is costly. Although it isn't yet clear what kind of satellite-enabled technology the plane was equipped with, there are clues. About 4:15 a.m. (10:15 p.m. EDT), Air France received an automatic message indicating an electrical circuit malfunction -- evidence that the plane was communicating via satellite.
Hansman said there is hope that the Air France pilots were able to "transmit in the blind" -- an attempt to reach pilots in nearby planes using their regular radios. "Aircraft in mid-ocean monitor the very high frequency channel and often talk to each other," he said. "It's possible that the Air France aircraft may have transmitted what was going on."