No Ordinary C Check

NASA calls the plane, which it acquired in 1985, "highly modified"--and it's not talking about the CFM56-2s that lifted the plane to -72 status. The aircraft hasnearly 150 specially installed instrumentsthat measure everything from ice sheet thickness to radar backscatter. It also hasa colorful history--both literally and figuratively.

It rolled off the assembly line in 1969 and spent a decade in service with Alitalia, carrying the name of Italian composer Giacomo Puccini.Its last commercial-service years were spent bathed in Braniff colors. (Blue, to be precise.)

Even its maintenance history is lively.

In February 2000, the crew was en route to Kiruna, Sweden as part of an Arctic ozone study. The crew's flight plan routed it 200 miles around what was believed to be the outer perimeter of a drifting ash cloud created by the eruption of Iceland's Mt. Hekla. But the ash cloud itself wasn't aware of the forecast, and the DC-8 flew right through it, capturing reams of data--and setting up $3 million in engine overhaul costs--in the process. Fromthe report on the incident:

Even though this was a diffuse ash cloud, the exposure was long enough and engine temperatureswere high enough that engine hot section blades and vanes were coated and cooling air passages werepartially or completely blocked. The uncooled blades still performed aerodynamically but necessitatedexpensive overhauls. The insidious nature of this encounter and the resulting damage was such thatengine trending did not reveal a problem, yet hot section parts may have begun to fail (through bladeerosion) if flown another 100 hr.