Comments about technological history, system fractures, and human resilience from James R. Chiles, the author of Inviting Disaster: Lessons from the Edge of Technology (HarperBusiness 2001; paperback 2002) and The God Machine: From Boomerangs to Black Hawks, the Story of the Helicopter (Random House, 2007, paperback 2008)

Sunday, March 30, 2014

The Search Will Go On, Pings or No Pings

Despite many breathless news reports about how time is running out on the battery life of digital voice and data recorder underwater locator beacons, TV-watchers should feel confident that the MH370 recovery effort won't stop after thirty days, or forty days either. There's too much at stake: we can't make fixes until we know the root cause, whether it's humans, mechanical, or electrical (I still lean to the latter). People will keep looking for answers, however long it takes.
Progress will begin once any wreckage is found, particularly if that includes structural components like wing spars. Structural parts and engines can help explain how the plane met the water: flat in a stall, nose down in a powerless dive,  or gliding as if under control.
One historical reminder that it's possible to solve profound aeronautical mysteries even without a "black box" DFDR is in this photo (credit, AFP):
 It's the plane in the background: A P3 Orion operated by the Japanese Maritime Self-Defense Force, the airframe of which is based on the Lockheed L-188 Electra, an airliner of the late 1950s (photo, Wiki Commons):

Early in its life as an airliner, the Electra presented a serious problem, two mysterious, mid-air airline disasters: one over Texas, and one over Indiana. As wings broke away and the airplanes fell to earth, the engines produced an eerie howl that bystanders described as unearthly. 

Work was hamstrung by the lack of flight data recorders on such aircraft. Result: the initial theories couldn't account for the full combination of the few facts that were known. 

But in time, study turned up the major causes behind it: propeller rotation that could resonate with the wing-bending frequency, and seemingly minor damage to engine mounts before the flights in question. The engine-mount damage had allowed the big propeller just enough wiggle room for the problem to catch hold.

After some pretty daring flight testing, Lockheed confirmed a set of solutions to what became known as whirl-mode flutter.

Here's a film of Electra tests at Langley:

Here's a snippet from a feature on flutter from Air&Space, "The Hammer," by Peter Garrison:

"As early as 1938, a study on powerplant vibrations had raised the possibility of propeller whirl inducing structural flutter. But the relative weights of engines and propellers, the stiffness of propeller shafts, and the engine power outputs that were typical in the late 1930s made it a practical impossibility. As Lockheed mathematician Robert Donham, who participated in the accident investigation, says today, 'Probably nobody involved with the design of the Electra even knew the paper existed. Nobody thought about whirl-mode vibrations causing flutter.'

"Lockheed's flutter analysts reprogrammed their computer to include whirl mode, and the mechanism of the accidents began to emerge. By an unlucky coincidence, the whirl-mode frequency of the Electra's big four-blade propellers happened to match the flapping frequency of the wing. The propellers, like the child driving a swing higher by small movements of her body, had eventually caused the wing to flap so violently that in 30 seconds it broke at the root without the propeller whirl ever overloading the nacelle structures.

"Microscopic examination of fractures in the wreckage of the two airplanes revealed engine mount damage that had preceded the inflight breakups. The cause of the earlier damage was uncertain--in one case a hard landing was suspected--but Lockheed redesigned the engine mounts and no Electra ever suffered from whirl-mode flutter again."

As did the catastrophic in-flight breakup of two Comet airliners in early 1954 over the Mediterranean, the troublesome beginnings of the Lockheed Electra L-188 proved the need for flight recorders. While both investigations eventually succeeded without such data, had good information been available right away from flight recorders, the later crashes might have been avoided. In short, time is of the essence.

Friday, March 21, 2014

Hunt for MH370: Time to put the X-37B to work

This would be a great time for the USAF to equip, launch, and employ the fast-reaction X-37B military spaceplane, an unmanned mini-shuttle that has already been up in orbit for extended-duration missions.

Yes, it's super-secret but it could pay its way.

It's likely that it can carry radar that would be well suited for detecting floating metal objects in the Indian Ocean if launched on a polar orbit.

My original post on this very cool craft is here.

Wednesday, March 19, 2014

MH370: Can we stop telling ghost stories now?

Whether or not the latest report about possible floating objects from MH370 in the southern Indian Ocean is accurate -- we'll know that in a short time -- I have to say the constant stream of conspiracy and murder theories parading across cable TV for the last week are simply maddening to families and (some) viewers. It's been completely lacking in rigor, founded on strings of thin speculation, and morphing to fit whatever tidbits sources and clueless authorities have passed along, even when those tidbits were retracted hours later.

Among the most ridiculous notions, in my mind:
  • That the schemers would thread a ridge-hugging route through the mountains at night so they could land and hold the airplane hostage, with the supposed reasons for this changing by the hour;
  • That they could keep an entire planeload of electronics-toting passengers silent as the plane flew over populated territories, including any pax with handheld satellite phones;
  • That the early, wild flight maneuvers soon after MH370 left its standard course were an attempt to evade radar; or
  • That the plane landed in a well-populated area but was hidden in a massive cover-up.
Certainly the course changes, timeline, and lack of communication make it hard for any theory to stand up so far, barring an electrical fire that knocked out a wide range of electronics and incapacitated the crew and passengers.

If the flight data recorder is ever found and recovered, we'll find out a lot. (It's possible that the voice recorder (CVR) may have been overwritten, though, if the aircraft continued for seven hours after whatever weird event took it from its course.)

Skeptics are free to criticize the "system failure" notion, but should acknowledge that the 777 for all its virtues has not been perfect, the failure of a navigational core unit on a Malaysia Air flight in 2005 (the ADIRU) being one example. In that case, an apparently impossible combination of events came very close to crashing the plane. Yes, Boeing has ordered thorough precautions against a repeat, but what other gremlins lie in wait?

With thorough flight automation, unfortunately, also comes the possibility of rare but terrifying failures.

Saturday, March 15, 2014

Malaysia Airlines 370: Intentional Destruction? Not so fast

I don't think intentional destruction by someone on board is the best fit for the the irregular public disclosures about MH370's flight path. While it makes sense for investigators to pursue that possibility, to me, it's a weak hypothesis.

Fly-by-wire jets are extremely complex devices with novel modes of failure (see the subject "sneak circuit analysis"), and a common cause such as an electrical fire in the avionics racks could help explain more than a few of the circumstances: the erratic flight path, a crew disabled by hypoxia, abrupt altitude changes, transponders going off line ... in any case, more posts to follow.

Monday, March 10, 2014

Malaysia Airlines Flight 370: A rare case

After almost three days, authorities tell us, there's not a trace of the Boeing 777-200ER flying as MH370 from Kuala Lumpur to Beijing.

One moment it's at Flight Level 350; the next it's off the radar. According to Reuters, Boeing reps say no ACARS messages were received after contact was lost. So all we have are bits of indirect evidence that might, or might not, link to whatever happened: a mumbled radio transmission, the fact that at least two passengers boarded with false passports.

As I described in this post about missing airliners, it is extremely rare (but not completely unprecedented) for a commercial airliner to disappear without a trace then go undetected for years. When I looked through the records, I only found one such case in modern times: a Pakistan International Airlines Fokker-27 turboprop with the call letters AP-BBF, which flew off into the mountains on August 25, 1989, with 54 souls. No piece of the AP-BBF, nor any human remains, have been found over a quarter century.

Here's a picture (

The commentators are correct in calling Flight 370 unprecedented in that the 777 has a very good safety record, and had locator electronics that are supposed to aid rescuers in finding whatever remains.

The original flight path was not over deep waters, which are colored dark blue in this map (map, NBC):

Normally the acoustic pingers embedded in Flight Data Recorders and Voice Data Recorders on such aircraft would make them relatively easy to find within a few days, in such shallow waters. This suggests either that a something destroyed the recorders over the ocean -- quite unlikely, given how tough they are -- or else the airplane is quite a distance from the last reported position. Search efforts are now expanding considerably to the west, in case the airplane headed that direction while off the radar screens (map, WashPost:)