I don't want to take sides in this discussion, I just wanted to share
some information about the Controlled Impact Demonstration (CID)--or as
it was known at Dryden, Crash In the Desert.
The story of what happened depends on who you talk to. I remember that
the FAA was not very happy with the crash. Dryden folks seemed to think
it was very successful. Having been there and somewhat involved in the
early stages of the flight test program, my personal assessment is that
the pilot screwed the pooch on this one.
The following is from the Dryden web pages:
Controlled Impact Demonstration (CID) Aircraft
In 1984 NASA Dryden Flight Research Center and the Federal Aviation
Administration (FAA) teamed-up in a unique flight experiment called the
Controlled Impact Demonstration (CID), to test the impact of a Boeing
720 aircraft using standard fuel with an additive designed to suppress
fire. The additive FM-9, a high molecular-weight long chain polymer,
when blended with Jet-A fuel had demonstrated the capability to inhibit
ignition and flame propagation of the released fuel in simulated impact
tests.
Antimisting kerosene (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 B-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 (G.E) to break down
and return the AMK to near Jet-A quality.
In addition to the AMK research the NASA Langley Research Center was
involved in a structural loads measurement experiment which included
having instrumented dummies filling the seats in the passenger
compartment. Before the final flight on December 1, 1984, more then four
years of effort passed trying to set-up final impact conditions
considered survivable by the FAA. During those years while 14 flights
with crews were flown the following major efforts were underway: NASA
Dryden developed the remote piloting techniques necessary for the B-720
to fly as a drone aircraft; General Electric installed and tested four
degraders (one on each engine); and the FAA refined AMK (blending,
testing, and fueling a full size aircraft). The 14 flights had 9
takeoffs, 13 landings and around 69 approaches, to about 150 feet above
the prepared crash site, under remote control. These flight 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. On the final flight
(No. 15) with no crew, all fuel tanks were filled with a total of 76,000
pounds of AMK and all engines ran from start-up to impact (the flight
time was 9 minutes) on the modified Jet-A.
The CID impact was spectacular with a large fireball enveloping and
burning the B-720 aircraft. From the standpoint of AMK the test was a
major set-back, but for NASA Langley, the data collected on
crashworthiness was deemed successful and just as important.
Some very interesting video is available at:
http://www1.dfrc.nasa.gov/Gallery/Movie/CID/640x/EM-0004-03.mov
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