The FAA will contract with Pratt & Whitney to modify an F117 turbofan engine—the military version of the PW2000—for a volcanic ash study involving NASA and the U.S. Air Force (USAF).

P&W’s F117 powers USAF’s C-17 four-engine military transport aircraft, one of which will be used for the study, which is scheduled to start in March. The study will involve injecting ash into the modified engine on the ground.

“A key element of this test is to provide a means for engine ingestion of volcanic ash, which requires engine modifications allowing for advanced sensor installation to provide critical experimental data during the testing,” says the FAA.

Known impacts of inflight volcanic ash ingestion include erosion of fan and compressor blades, blocking of air cooling paths, engine oil contamination and damage to combustors and high-pressure turbine blades.

The contamination can cause compressor stalls, overheating and flame-outs, says the FAA. “Installed ground engine testing on USAF C-17A airplane provides a unique opportunity to utilize advanced instrumentation and sensor capability along with simulating a range of environmental conditions, such as volcanic ash, while capturing system-level response on both the engine and aircraft level,” the agency adds.