Friday, September 07, 2007

Sacrifices to the Sky God

Matt found and sent along this item that tells how the Nepalese national airline deals with aircraft maintenance problems:

"Officials at Nepal's state-run airline have sacrificed two goats to appease Akash Bhairab, the Hindu sky god, following technical problems with one of its Boeing 757 aircraft, the carrier said Tuesday. "

We of course, found this an intriguing custom and it turned out that Libby Bodio, who has spent considerable time in Nepal, had some first hand experience of it:

" The first time I went to Kathmandu (October 1972) we arrived just as Desain(I'm pretty sure that is what the main fall harvest festival was called) was starting. At that point there were only two flights a week into Kathmandu from Delhi. When we landed and pulled up to the airport buildings (the planes still used ladders to exit), there were several people in airport uniforms with a goat ready to be offered up to the airline gods...considering the state of the plane, it needed all the help it could get, and we figured that a goat sacrifice wouldn't hurt its chances of staying aloft any. They slit its throat, and dragged it over to the front of the plane (a small jet -- 727 maybe?) just under the pilot's seat, and smeared blood on it while reciting some prayers, and the stuck marigold flower petals on it.

On the taxi ride into town we saw lots more goats being led along for the family feast as well as chickens being killed under the opened hoods of the few cars (mostly small Datsuns and Toyotas then), the blood being directed towards the valve covers. Everyone was very happy -- it had been a good harvest and relatives dressed in their finest were traveling to all corners of the country to give thanks and share in the bounty. And the smells coming from the houses were mouth-watering. All government offices were closed for several days, and there were no flights anywhere because they figured (correctly) that all the pilots participating in the festivities would be drunk.

So everyone had a splendid time, and so did we, enjoying extra time in Kathmandu -- everything was new to us, and the sights, sounds, and smells really sucked us in. I'm glad to hear that goats are still being offered up to the airline gods-- God only knows what might have happened without the help of the goats."

Well, this sounds like an interesting custom in a culture very different from ours, but my experience working in aerospace showed me that we really aren't all that different. In fact, in this country the Federal Aviation Administration requires animal sacrifices to certify jet engines!

Great hazards in operating aircraft lie in bird strikes and bird ingestion. Birds sucked into engines can cause them to stall and planes to crash. Actually one of the early operational B-1B bombers crashed because of geese that were sucked into the engines.

So during the testing to certify new engines there are requirements to simulate bird ingestion. You can see the FAA regulation that tells of the size and number of birds that must be used here. Test engines are run out in the open on the ground in test stands. To simulate ingestion at altitude, chicken, goose, and game hen carcasses are fired by a gas cannon into the engine intake at the speed that the airplane would be going. Here is a YouTube clip of a bird ingestion test on a Rolls-Royce engine.

The tests have to show that the engine can take that and keep running or if it causes internal engine rupture that the dislodged parts stay within the engine nacelle (housing) and don't emerge to cause "fratricidal" damage in other engines or to the fuselage. Most modern nacelles have a light layer of kevlar armor in them to try to contain the worst of these.

Bird strikes are such a serious issue that many airports take serious measures to keep birds away from their runways. Here's a good rundown of some of these from the Wikipedia article:

"To reduce birdstrikes on take off and landing, airports invest in bird management and control. This includes changes to terrain around the airport to reduce its attractiveness as a habitat for birds. Things attractive to birds like landfill sites, water areas, and trees.

Other approaches try to scare away the birds using frightening devices, for example sounds, lights, pyrotechnics, radio-controlled airplanes, decoy animals/corpses, lasers, dogs etc. Firearms are also occasionally employed.

A tremendously successful approach in recent years has been the utilization of border collie dogs to scare away birds and wildlife. Another alternative is bird capture and relocation.

Falcons are sometimes used to cut down the bird population, as for example on John F. Kennedy International Airport. At Manchester Airport in England the usual type of falcon used for this is a peregrine falcon/lanner hybrid, as its habitual flight range is about the right size to cover the airport and not also much irrelevant land around."

You knew we'd have to get to falconry eventually, didn't you? Above is a picture of Steve's friend Tom Donald in Saskatchewan, a falconer, saluki man, pioneer in partnering hounds and hawks, and pigeon flyer. Tom makes a living clearing Canadian airfields with his birds. This pic shows him him with an airport control bird.

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