#MalaysiaAirlines, #MH370,
#PrayForMH370
Emergency Beacons Not Fool-Proof When Jets Go Missing
As the hunt for the missing Malaysia
Airlines jet continues, experts say it's not surprising that no
emergency signals have been picked up — especially if the plane is
underwater.
When a commercial plane crashes, an emergency locator transmitter
(ELT) is designed to switch on automatically to send a signal to help
searchers find the crash site. But they don't always work, and it is not
clear that the missing jet did crash.
"ELTs in general are
extremely reliable, but it's not surprising — there's always a chance
the system didn't work for some reason," said aviation safety expert
Todd Curtis, the founder of AirSafe.com. That reason could include a major crash.
In
fact, a 2009 report from the Airplane Owners and Pilots Association
said even newer ELTs successfully activate only about 82 percent of the
time. The original generation of ELTs, which came out in 1973, had an
activation rate of 25 percent, but that has improved over the decades.
Boeing
declined to comment on the type of ELT with which the missing Malaysia
Airlines Boeing 777-2H6 was outfitted. Curtis — who worked as an airline
safety engineer at Boeing for more than eight years — pointed out that
the airline could have updated the craft's ELT anyway.
ELT signals are meant to continue
broadcasting for 30 days, Curtis said, and they may be picked up by a
variety of technology including satellites and aircraft searching
overhead.
But that's only if the plane and ELT are on land. If the plane is underwater, that poses a new set of problems.
"If the airplane had
crashed on land and survived the impact, then there’s a probability that
the actual ELT would still be working," former National Transportation
Safety Board investigator Greg Feith said on TODAY on Saturday. "But when it goes into the water, it’s a whole different story."
In
that case, the plane's so-called black box has an Underwater Locator
Beacon that "pings" out sound when submerged. But that would require
searchers to be close enough to pick up the sound.
"You won’t get that signal above water, over the top of the water, using an airplane trying to find a signal,” Feith told TODAY.
David
Gallo, the director of special projects at Woods Hole Oceanographic
Institution, said he has “very little faith in pingers." Gallo served as
the co-leader of the search for Air France 447, which plunged into the mid-Atlantic in 2009.
The main problem with relying on pingers, he said, is that “the ocean can play a lot of tricks with sound."
NBC News' Alan Boyle and Matthew DeLuca contributed to this report.
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