In 1984, NASA's Dryden Flight Research Center, now NASA Armstrong, and the Federal Aviation Administration teamed up in a unique flight experiment called the Controlled Impact Demonstration to test a promising fuel additive for retarding or suppressing fire in a real-world aircraft crash-landing scenario. When blended with standard Jet-A fuel, the FM-9 additive, a high molecular weight long-chain polymer, had demonstrated the capability to inhibit ignition and flame propagation of the released fuel in simulated impact tests. An obsolete Boeing 720 four-engine airliner was obtained from the Federal Aviation Administration for the project, which would conclude with an intentional crash-landing of the remotely piloted aircraft into several steel structures set up on the bed of Rogers Dry Lake at Edwards Air Force Base to breach the fuel tanks in the wings. This anti-misting kerosene with the FM-9 additive could not be introduced directly into a gas turbine engine due to several potential problems, such as clogging of filters. The modified fuel had to be restored to nearly Jet-A standard before being introduced into the engine for burning. This restoration was accomplished on the Boeing 720 using a device called a degrader that was installed on each of the aircraft's four Pratt & Whitney JT3C-7 engines.