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When a Super Cub ran out of fuel and had to land on uninhabited Kayak lsland in Alaska in May 2011, the pilot and passenger tried both low- and high-tech alerts. In addition to the “SOS,” they activated a SPOT beacon, and were rescued by the Coast Guard. (USCG/LT. Jon Bartel)

How to Find a Missing Airplane

Airplanes can vanish without a trace. Why is effective tracking technology being ignored?

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The morning of December 9, 2009, began cool and clear. In Dorrigo, an Australian town about 300 miles north of Sydney, the pilot of a Bell 206L-1 Long­Ranger helicopter took off on his second flight of the day. The 29-year-old (officials did not release his name) was under contract with the New South Wales National Parks and Wildlife Service to aid crews fighting bushfires. Also aboard was Aaron Harber, a 41-year-old park ranger being ferried to Cathedral Rock National Park, where he would help battle a blaze.

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At 11:20 a.m., a few minutes after takeoff, the pilot flew into a thick fog. He immediately lost all visual reference points. For a split second he glimpsed a ridgeline and a cluster of trees, then nothing. He knew he was perilously close to the ground—perhaps just 20 feet above it—but had no idea what direction he was traveling in. “This is not good,” he told Harber. “I’m going to try to land.” When the pilot yanked the cyclic to flare the chopper and slow its speed, there was a loud bang, and the LongRanger went into a flat spin. The main rotor snapped and sliced through the cockpit canopy just as the aircraft slammed into the ground. In the impact, Harber’s seatbelt shoulder harness was severed.

Harber died in the accident, but the pilot survived. With severe injuries to his head, chest, and back, he used his cell phone to call for help, but couldn’t tell rescuers where he was. It didn’t matter. Search teams were already en route, having been summoned by a tiny device called a Spider S2. Not much larger than a bagel, the $1,800 Spider, affixed to the Bell’s cockpit dash, had powered up automatically on takeoff and transmitted its whereabouts throughout the flight, in two-minute intervals, to a constellation of Iridium satellites, leaving a digital trail—“breadcrumbs”—that showed its latitude, longitude, altitude, airspeed, and bearing. Its flight data was stored on computer servers operated by New Zealand-based Spidertracks, the company that invented the Spider.

When the device was destroyed in the Dorrigo crash, it stopped leaving breadcrumbs. The silence told the software on the Spidertracks servers to begin dispatching a series of e-mails and text messages to a list of emergency contacts compiled earlier. On the list was Mark Rogers, whose firm, Commercial Helicopters, owned the Bell 206. Rogers notified authorities, using the breadcrumb data to direct searchers to the exact location of the impact. Rescuers found the pilot in critical condition. He was airlifted to a hospital, and he eventually recovered.

The helicopter was also carrying an emergency locator transmitter, or ELT, which contains a G-switch (“G” for gravity). When it senses a hard impact, the G-switch transmits a distress signal. But ELTs rely on a sparse network of satellites that get crummy reception, and it took more than 90 minutes for the ELT to be heard and its position conveyed to monitoring stations on the ground. By that time, “the whole recovery operation was well under way,” Spidertracks co-founder and helicopter pilot Bruce Bartley says. The Spider’s early alert had likely saved the pilot’s life.

Adventurer-aviator Steve Fossett wasn’t so lucky when his Bellanca Super Decathlon plowed into a mountain near Mammoth Lakes, California, in September 2007 (see “Anatomy of a Search,” Feb./Mar. 2008). He carried an older-generation ELT, and if it sent distress signals, no one received them. More than a year later, searchers found his remains a half-mile from the crash site. The seat belts in the Bellanca had been unbuckled. Fossett appears to have survived the impact and staggered away from his airplane before he died. If he’d had a breadcrumb tracker, the distress calls, set in motion at almost the moment of the crash, might have alerted authorities in time to save him.

Under legislation passed by Congress 35 years ago and enforced by the Federal Aviation Administration, virtually every aircraft in the United States must have an ELT. But when an airplane with an ELT crashes, its location is transmitted only if the device calls for assistance. And there are any number of ways the device can be stopped from sending those alerts.

There are two types of ELT: the older models, which were introduced in 1973, transmit over 121.5 megahertz, an analog frequency, while newer beacons, which debuted in 1999, use 406 megahertz and broadcast digitally. The 406 ELTs are an improvement over the 121.5s because the digital signal can carry GPS coordinates, along with beacon registration data, such as the airplane’s owner and contact information.

Most organizations that are involved in aviation safety believe that 121.5 ELTs should be replaced with 406s. Searchers can get a fix on a 406 unit’s position in as little as five minutes (though gaps in global satellite reception can extend that to 15 minutes, and if the unit doesn’t have an optional GPS accessory, the delay can be as long as three hours or more).

The older ELTs are so unreliable that as of February 1, 2009, Cospas-Sarsat, the multi-national entity charged with monitoring ELT transmissions, stopped listening to 121.5 megahertz. If an airplane outfitted with a 121.5 unit gets in trouble, its cries will now almost always go unheard. The FAA had hoped pilots would swap their 121.5 units for 406s. But no federal law requires them to, and installation of a new unit costs of up to $2,000. Says agency spokeswoman Alison Duquette: “The FAA’s position is that 406 ELTs are superior, but their cost [to the pilots] would not justify mandating them.” To date, only about 25,000 general aviation aircraft have upgraded units. Translation: Of the 224,172 active general aviation aircraft in the United States, about 90 percent operate with an emergency beacon that transmits its distress signal over a frequency that is not listened to. If one of these aircraft should crash, hearing its ELT is a matter of pure luck. A passing pilot might pick up the signal—but only if he or she happens to be tuned to the frequency.

EMERGENCY BEACONS ARE USED in many environments: aviation, marine, and terrestrial. Cospas-Sarsat relays distress alerts to the Air Force Rescue Coordination Center at Tyndall Air Force Base in Florida, which coordinates searches in the United States among various federal, state, and local agencies. In theory, ELTs should enable authorities to rapidly locate downed aircraft. In practice, they fail miserably. In the last five years, the AFRCC has been directly involved in 416 crashes in the United States that required some manner of search and rescue (often hundreds more occur, but are usually handled at the state and local levels). Each of these airplanes carried (or by law should have carried) an ELT. Yet in these accidents, just 124 ELTs activated. A five-year NASA study that analyzed the performance of 121.5 ELTs (comparable data from the 406 transmitters isn’t yet available) in 3,270 crashes shows that in 75 percent of accidents, the beacons are disabled on impact or destroyed in a fire, and never activate.

The units are installed inside the cabin near the tail, where they’re most likely to survive a crash. Their exterior antennas—mounted to the top of the fuselage, usually behind the wing, or forward of the tail rotor on helicopters—can easily snap. In 2005, 49-year-old New Zealand billionaire liquor baron Michael Erceg crashed his Eurocopter EC120B in a remote forest south of Auckland; he and a passenger were killed. The ELT antenna broke, so the distress pings went unheard. The ensuing hunt for Erceg would become one of the largest and most expensive search-and-rescue operations ever conducted in New Zealand.

Four years after Erceg died, Spidertracks enlisted the support of his widow, Lynne, in a marketing effort to help subsidize the price of Spiders for New Zealand pilots. The pitch to aviators: Breadcrumb trackers like the Spider don’t use an external antenna. Instead, they affix to the dash and transmit through the windscreen.

Even if the crash leaves an ELT and its antenna intact, the unit can’t transmit if the aircraft is upside down, under water, or concealed in dense foliage. And if the pilot, trying to lessen the crash’s impact, lands too gently, the G-switch can fail to arm.

When ELTs do work properly, rescue is virtually guaranteed. “There are no open [accident] cases in the U.S. that I’m aware of where an ELT activated but for whatever reason we haven’t found the wreck site,” says Shawn Maddock, a Cospas-Sarsat operations support officer.

About Michael Behar

Based in Boulder, Colorado, Michael Behar (michaelbehar.com) writes about aerospace, adventure travel, science, and the environment.

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