Controlled Impact Demonstration
Encyclopedia
The Controlled Impact Demonstration (or colloquially the Crash In the Desert) was a joint project between NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 and the Federal Aviation Administration
Federal Aviation Administration
The Federal Aviation Administration is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of civil aviation in the U.S...

 (FAA) aimed at acquiring data, as well as demonstrating and testing new technologies, with the intent of improving occupant crash survivability, by crashing a Boeing 720
Boeing 720
The Boeing 720 is a four-engine narrow-body short- to medium-range passenger jet airliner. Developed by Boeing in the late 1950s from the Boeing 707, the 720 has a shorter fuselage and less range...

 aircraft. The tests involved the efforts of NASA Ames Research Center
NASA Ames Research Center
The Ames Research Center , is one of the United States of America's National Aeronautics and Space Administration 10 major field centers.The centre is located in Moffett Field in California's Silicon Valley, near the high-tech companies, entrepreneurial ventures, universities, and other...

, Langley Research Center
Langley Research Center
Langley Research Center is the oldest of NASA's field centers, located in Hampton, Virginia, United States. It directly borders Poquoson, Virginia and Langley Air Force Base...

, Dryden Flight Research Center
Dryden Flight Research Center
The Dryden Flight Research Center , located inside Edwards Air Force Base, is an aeronautical research center operated by NASA. On March 26, 1976 it was named in honor of the late Hugh L. Dryden, a prominent aeronautical engineer who at the time of his death in 1965 was NASA's deputy administrator...

, the FAA, and General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...

, and required more than 4 years of work before the test occurred. The aircraft was remotely controlled
Unmanned aerial vehicle
An unmanned aerial vehicle , also known as a unmanned aircraft system , remotely piloted aircraft or unmanned aircraft, is a machine which functions either by the remote control of a navigator or pilot or autonomously, that is, as a self-directing entity...

 for the tests, and numerous test runs were undertaken prior to performing the actual impact. The impact test flight occurred on December 1, 1984, proceeding generally according to plan, and resulting in a spectacular fireball which required more than an hour to extinguish.

The test resulted in a finding that the antimisting kerosene test fuel was insufficiently beneficial, and that several changes to equipment in the passenger compartment of aircraft were needed. The FAA concluded that about ¼ of the passengers would have survived, while NASA concluded that a head-up display
Head-Up Display
A head-up display or heads-up display is any transparent display that presents data without requiring users to look away from their usual viewpoints...

 along with microwave landing system
Microwave landing system
A microwave landing system is an all-weather, precision landing system originally intended to replace or supplement instrument landing systems...

 would have assisted in piloting the craft.

Background and experiment setup

NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 and the Federal Aviation Administration
Federal Aviation Administration
The Federal Aviation Administration is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of civil aviation in the U.S...

 (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
Edwards, California
Edwards is an unincorporated community in Kern County, California.It is located east-southeast of Mojave, at an elevation of 2356 feet ....

, using a remotely controlled
Unmanned aerial vehicle
An unmanned aerial vehicle , also known as a unmanned aircraft system , remotely piloted aircraft or unmanned aircraft, is a machine which functions either by the remote control of a navigator or pilot or autonomously, that is, as a self-directing entity...

 Boeing
Boeing
The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...

 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 additive FM-9, a high molecular-weight long chain polymer
Polymer
A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...

, 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.

In addition to the AMK research, NASA Langley Research Center
Langley Research Center
Langley Research Center is the oldest of NASA's field centers, located in Hampton, Virginia, United States. It directly borders Poquoson, Virginia and Langley Air Force Base...

 was involved in a structural load measurement experiment, which included using instrumented crash dummies filling the seats in the passenger compartment. Before the final flight on December 1, 1984, more than four years of effort was expended in attempting to set up final impact conditions which would be considered to be survivable by the FAA.

AMK cannot be introduced directly into a gas turbine
Gas turbine
A gas turbine, also called a combustion turbine, is a type of internal combustion engine. It has an upstream rotating compressor coupled to a downstream turbine, and a combustion chamber in-between....

 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 720 using a device called a "degrader". Each of the four Pratt & Whitney JT3C
Pratt & Whitney JT3C
|-Specifications :-See also:-References:NotesBibliography* Francillon, René J. McDonnell Douglas Aircraft since 1920. London: Putnam, 1979. ISBN 0-370-00050-1.-External links:* * *...

-7 engines had a "degrader" built and installed by General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...

 (GE) to break down and return the AMK to near Jet-A quality.

Over a series of 14 flights, General Electric installed and tested four degraders (one on each engine); and the FAA refined AMK (blending, testing, and fueling a full size aircraft). During the flights the aircraft made approximately 69 approaches, to about 150 feet (45.7 m) 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
Dryden Flight Research Center
The Dryden Flight Research Center , located inside Edwards Air Force Base, is an aeronautical research center operated by NASA. On March 26, 1976 it was named in honor of the late Hugh L. Dryden, a prominent aeronautical engineer who at the time of his death in 1965 was NASA's deputy administrator...

 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, because if the uplink failed the ground based pilot would no longer have control of the aircraft.

Test execution

On the morning of December 1, 1984, the test aircraft took off from Edwards Air Force Base, California, made a left-hand departure and climbed to an altitude of 2300 feet (701 m). The aircraft was remotely flown by NASA research pilot Fitzhugh Fulton from the NASA Dryden Remotely Controlled Vehicle Facility. All fuel tanks were filled with a total of 76000 pounds (34,473 kg) of AMK and all engines ran from start-up to impact (the flight time was 9 minutes) on the modified Jet-A. It then began a descent-to-landing along the roughly 3.8-degree glideslope to a specially prepared runway on the east side of Rogers Dry Lake
Rogers Dry Lake
Rogers Dry Lake is an endorheic desert salt pan in the Mojave Desert of Kern County, California. The lake derives its name from the Anglicization from the Spanish name, Rodriguez Dry Lake. It is the central part of Edwards Air Force Base as its hard surface provides a natural extension to the...

, with the landing gear
Landing Gear
Landing Gear is Devin the Dude's fifth studio album. It was released on October 7, 2008. It was his first studio album since signing with the label Razor & Tie. It features a high-profile guest appearance from Snoop Dogg. As of October 30, 2008, the album has sold 18,906 copies.-Track...

 remaining retracted.

Passing the decision height of 150 feet (45.7 m) above ground level (AGL), the aircraft turned slightly to the right of the desired path. The aircraft entered into a situation known as a Dutch Roll
Dutch roll
Dutch roll is a type of aircraft motion, consisting of an out-of-phase combination of "tail-wagging" and rocking from side to side. This yaw-roll coupling is one of the basic flight dynamic modes...

. Slightly above that decision point at which the pilot was to execute a "go-around
Go-around
A go-around is an aborted landing of an aircraft that is on final approach.- Origin of the term :The term arises from the traditional use of traffic patterns at airfields. A landing aircraft will first join the circuit pattern and prepare for landing in an orderly fashion...

", there appeared to be enough altitude to maneuver back to the center-line of the runway. The aircraft was below the glideslope and below the desired airspeed. Data acquisition systems had been activated, and the aircraft was committed to impact. It contacted the ground, left wing low, at full throttle, with the aircraft nose pointing to the left of the center-line.

It was planned that the aircraft would land wings-level, with the throttles set to idle, and exactly on the center-line during the CID, thus allowing the fuselage
Fuselage
The fuselage is an aircraft's main body section that holds crew and passengers or cargo. In single-engine aircraft it will usually contain an engine, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage which in turn is used as a floating hull...

 to remain intact as the wings were sliced open by eight posts cemented into the runway (called "Rhinos" due to the shape of the "horns" welded onto the posts). The Boeing 720
Boeing 720
The Boeing 720 is a four-engine narrow-body short- to medium-range passenger jet airliner. Developed by Boeing in the late 1950s from the Boeing 707, the 720 has a shorter fuselage and less range...

 landed askew. One of the Rhinos sliced through the number 3 engine, behind the burner can, leaving the engine on the wing pylon (which does not typically happen in an impact of this type). The same rhino then sliced through the fuselage, causing a cabin fire when burning fuel was able to enter the fuselage. The cutting of the number 3 engine and the full throttle situation was significant as this was outside the test envelope. The number 3 engine continued to operate, degrading the fuel and igniting it after impact, providing a significant heat source. The fire and smoke took over an hour to extinguish. The CID impact was spectacular with a large fireball created by the number 3 engine on the right side, enveloping and burning the 720 aircraft. From the standpoint of AMK the test was a major set-back. For NASA Langley, the data collected on crash-worthiness was deemed successful and just as important.

Findings

The actual impact demonstrated that the antimisting additive tested was not sufficient to prevent a post-crash fire in all circumstances, though the reduced intensity of the initial fire was attributed to the effect of AMK.

FAA investigators estimated that 23–25% of the aircraft's full complement of 113 people could have survived the crash. Time from slide-out to complete smoke obscuration for the forward cabin was five seconds; for the aft cabin, it was 20 seconds. Total time to evacuate was 15 and 33 seconds respectively, accounting for the time necessary to reach and open the doors and operate the slide. Investigators labeled their estimate of the ability to escape through dense smoke as "highly speculative".

As a result of analysis of the crash, the FAA instituted new flammability standards for seat cushions which required the use of fire-blocking layers, resulting in seats which performed better than those in the test. They also implemented a standard requiring floor proximity lighting to be mechanically fastened, due to the apparent detachment of two types of adhesive-fastened emergency lights during the impact. Federal aviation regulations for flight data recorder
Flight data recorder
A flight data recorder is an electronic device employed to record any instructions sent to any electronic systems on an aircraft. It is a device used to record specific aircraft performance parameters...

 sampling rates for pitch, roll and acceleration were found to be insufficient.

NASA concluded that the impact piloting task was of an unusually high workload, which might have been reduced through the use of a heads-up display, the automation of more tasks, and a higher-resolution monitor. They also recommended the use of a microwave landing system
Microwave landing system
A microwave landing system is an all-weather, precision landing system originally intended to replace or supplement instrument landing systems...

 to improve tracking accuracy over the standard ground radar provided by an instrument landing system
Instrument Landing System
An instrument landing system is a ground-based instrument approach system that provides precision guidance to an aircraft approaching and landing on a runway, using a combination of radio signals and, in many cases, high-intensity lighting arrays to enable a safe landing during instrument...

 (in practice, the Global Positioning System
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

-based Wide Area Augmentation System
Wide Area Augmentation System
The Wide Area Augmentation System is an air navigation aid developed by the Federal Aviation Administration to augment the Global Positioning System , with the goal of improving its accuracy, integrity, and availability...

came to fulfill this role).
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