Reality check: Could MH370 have hidden from radar next to another plane?

BOSTON — It’s the Malaysia Airlines missing jet theory that has taken the internet by storm.

Ohio aviation hobbyist and IT professional Keith Ledgerwood dug deep into the data and emerged with the idea that — after making the sharp left everyone seems to now agree on — flight MH370 appears to have piggybacked on another aircraft, Singapore Airlines Flight 68, which also departed Kuala Lumpur around the same time.

In doing so, the theory goes, it could have evaded radar detection. Unlike MH370, which was heading for Beijing, SIA68’s destination was Madrid. Its flight path passed over parts of India, Pakistan, and Afghanistan, after which the Malaysian Boeing 777 could have peeled off and landed in the desert or in Central Asia.

The hypothesis, replete with charts and technical details, is compelling. But is it feasible?

Yes it is, according to Massachusetts Institute of Technology professor of aeronautics and astronautics R. John Hansman Jr.

But it’s not very likely.

An airplane as big as a Boeing 777 can effectively hide from radar systems, Hansman says, if it gets close enough to another plane of similar size. Hansman is also the director of MIT’s International Center for Air Transportation.

Speaking to GlobalPost Tuesday, he said he was familiar with Ledgerwood’s idea, and termed it “technically possible but operationally very difficult.”

Hansman said with planes of that size, “you don’t have to get that close — within a half-mile or a quarter-mile” to appear on radar screens as, effectively, part of the same plane, even on military radar.

“It would be a slightly larger radar blip, but not enough to get anybody’s attention,” Hansman said. Since radar operators would be expecting to see a contact at that speed and on that flight path — they would be assuming it was only SIA68 — they would not see anything worrying.

However, maneuvering two massive aircraft that close together in flight at high altitude is extremely hard, he said.

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First, while the flights departed from the same airport, “it’s hard to catch up with the other airplane.” Big airliners don’t have much of a range of possible speeds, especially when flying at cruising altitudes, so it’s not like the Malaysia Airlines pilot could have done the airplane equivalent of stepping on the gas pedal — it would have already been quite near the floor.

If it was possible to catch up with speed, the Malaysian pilots would have had a challenge locating the Singapore Airlines plane — having turned off their transponder and anti-collision signaling systems, that equipment would have been useless to provide other planes’ whereabouts.

Transponder silence also would have prevented the Singapore Airlines plane from noticing it had a shadower, Hansman said, as airplanes’ on-board primary radar is designed to detect weather, not other aircraft.

Even assuming MH370 could catch up to, find, close in with, and shadow SIA68 in the middle of the night over the ocean, “at some point you’re going to have to separate” and fly elsewhere, Hansman said. “Then you have to land it somewhere.”

As suggested by another aviation expert speaking to GlobalPost, being certain of escaping radar detection all the way to landing at a remote airstrip would mean discovering and evading secret military radar capabilities, or at least being absolutely sure that the nations in question would not want to expose their technological expertise by sharing information those systems might have detected.

Hansman discounts the possibility of a thief having run off with the plane because “it’s easier to just go out on the ramp and steal an airplane” than to gain enough expertise to accomplish what Ledgerwood’s hypothesis suggests, and then to go and actually execute it.

He is more persuaded by an idea he and others have been discussing for several days: The possibility of some sort of onboard emergency, an electrical malfunction or a fire, like that described in a Wired post earlier Tuesday.

“The original turnback” — the one Ledgerwood thinks was to chase SIA68 — “was in a direction toward an appropriate emergency-diversion field,” Hansman said.

But even that change raises questions for him: In an emergency, pilots wouldn’t likely have taken the time to use the flight computer, but would instead have changed the plane’s heading manually. And if there was time to use the computer, he said, there would have probably been time to make a radio call announcing the problem.

But Hansman said the basic assumption of Ledgerwood’s idea is true: Only very high-tech radars can tell the difference between two planes traveling close together at altitude, and many countries in South Asia may not have that equipment. In fact, “we hope not,” Hansman said.

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