Controlled Impact Demonstration

The Controlled Impact Demonstration (or colloquially the Crash In the Desert) was a joint project between NASA and the Federal Aviation Administration (FAA) that intentionally crashed a remotely controlled Boeing 720 aircraft to acquire data and test new technologies to aid passenger and crew survival. The crash required more than four years of preparation by NASA Ames Research Center, Langley Research Center, Dryden Flight Research Center, the FAA, and General Electric. After numerous test runs, the plane was crashed on December 1, 1984. The test went generally according to plan, and produced a large fireball that required more than an hour to extinguish.

The FAA concluded that about one-quarter of the passengers would have survived, that the antimisting kerosene test fuel did not sufficiently reduce the risk of fire, and that several changes to equipment in the passenger compartment of aircraft were needed. NASA concluded that a head-up display and microwave landing system would have helped the pilot more safely fly the aircraft.

Background and experiment setup

NASA and the Federal Aviation Administration (FAA) conducted a joint program for the acquisition, demonstration, and validation of technology for the improvement of transport aircraft occupant crash survivability using a large, four-engine, remotely piloted transport airplane in a controlled impact demonstration (CID). The CID program was conducted at the Dryden Flight Research Facility of NASA Ames Research Center (Ames-Dryden), at Edwards, California, using a remotely controlled Boeing 720 transport, and was completed in late 1984. The objectives of the CID program were to demonstrate a reduction of postcrash fire through the use of antimisting fuel, acquire transport crash structural data, and to demonstrate the effectiveness of existing improved seat-restraint and cabin structural systems.

The Boeing 720 (tail number N833NA) was purchased new by the FAA in 1960 as a training aircraft. After more than 20,000 hours and 54,000 takeoff and landing cycles, it had come to the end of its useful life. The aircraft was turned over to NASA-Ames/Dryden Flight Research Center for the CID program in 1981.

The additive, ICI's FM-9, a high molecular-weight long chain polymer, when blended with Jet-A fuel, forms antimisting kerosene (AMK). AMK had demonstrated the capability to inhibit ignition and flame propagation of the released fuel in simulated impact tests. AMK cannot be introduced directly into a gas turbine engine due to several possible problems such as clogging of filters. The AMK must be restored to almost Jet-A before being introduced into the engine for burning. This restoration is called degradation and was accomplished on the Boeing 720 using a device called a degrader. Each of the four Pratt & Whitney JT3C-7 engines had a degrader built and installed by General Electric (GE) to break down and return the AMK to near Jet-A quality.

In addition to the AMK research, NASA Langley Research Center was involved in a structural load measurement experiment, which included using instrumented crash dummies in the seats of the passenger compartment and cockpit. Before the final flight in 1984, more than four years of effort was expended in attempting to establish final impact conditions which would be considered to be survivable by the FAA.

Over a series of 14 flights, General Electric installed and tested four degraders (one on each engine); the FAA refined AMK, blending, testing, and fueling a full size aircraft. During the flights the aircraft made approximately 69 approaches, to about 150 ft above the prepared crash site, under remote control. These flights were used to introduce AMK one step at a time into some of the fuel tanks and engines while monitoring the performance of the engines. During those same flights, NASA's Dryden Flight Research Center also developed the remote piloting techniques necessary for the Boeing 720 to fly as a drone aircraft. An initial attempt at the full-scale test was scrubbed in late 1983 due to problems with the uplink connection to the 720; if the uplink failed the ground-based pilot would no longer have control of the aircraft.