History of s/n 79-10783
Thus far, only a handful of early model Lockheed Martin F-117A Nighthawk airframes have been preserved for public display. One of these, a YF-117A full-scale development prototype, was added to the Air Force Flight Test Museum collection in 2008 following extensive demilitarization and restoration efforts by personnel from the 410th Flight Test Squadron at Air Force Plant 42 in Palmdale. This milestone event was the culmination of nearly two decades of planning by Museum staff and Air Force officials who had to wait for the Nighthawk fleet to enter its retirement phase, and until the airframe destined for display was no longer needed for testing.
Ship 783, the fourth YF-117A, was originally delivered to the test site inside a C-5A cargo plane on December 5, 1981, but due to nose wheel steering problems and additional time necessary to prepare the aircraft’s surface to meet operational stealth requirements, it did not fly until seven months later. After Lockheed pilot Tom Morgenfeld flew an initial checkout sortie on July 7, 1982, the airplane was permanently assigned to the Senior Trend Joint Test Force, known to team members as the Baja Scorpions. Ship 783 was nicknamed “Scorpion 4” and had been designated the primary airframe for low observables (LO) testing.
Early testing included infrared (IR) signature measurements taken during flight from a specially modified NKC-135A, as well as by F-4D fighters equipped with Supersonic Airborne Infrared Measurement System (SAIMS) and Beam Approach Seeker Evaluation System (BASES) pods. Radar cross-section (RCS) measurements began in September 1982, and for the next several months, Scorpion 4 was exposed to a wide variety of U.S. and Soviet-type threat systems for RCS and IR signature testing.
In February 1983, maintenance technicians installed an extension trapeze in the weapons bay. Scorpion 4 soon alternated between LO tests and weapons-delivery trials involving 20-pound practice bombs and 2,000-pound full-scale weapons. The airplane also served as a testbed for a variety of avionics systems.
From April 24 to July 23, 1984, Article 783 was flown against F-14, F-15, F-16, and EF-111A aircraft to collect air-to-air threat analysis data from several types of radar. Afterward, the airplane was used for further LO tests and integration of navigation and weapon delivery systems. Capt. William Aten piloted Scorpion 4’s 100th sortie on May 8, 1984.
In October 1984, Navy pilots Lt. Cmdr. Kenny Linn and Lt. Cmdr. Ken Grubbs conducted a performance review to evaluate the F-117A for aircraft carrier suitability. Three of eight flights were made in Ship 783, with the remainder made in Article 782. The naval aviators found landing speeds were too high and sink rate limits too low for carrier operations.
In April 1986, Ship 783 served as a testbed for a night-vision goggle system. In September of that year, the airplane was flown 31 times in a single month – once flying four sorties in a single day – and by February 1987 the airframe had logged 600 flight hours. Lt. Col. Craig Dunn flew the 500th sortie in 783 on June 19, 1987. In March 1989, Scorpion 4 was officially transferred from the contractor to the Air Force after 830 hours of flying. By March 1990, the airframe had logged 900 flight hours.
When the existence of the F-117A was declassified in November 1988, the Pentagon released only a single dark, grainy image to news media. By chance, it happened to be a picture of Scorpion 4.
In 1992, after the Baja Scorpions relocated to Air Force Plant 42 to become the 410th FLTS, Scorpion 4 continued to serve as the squadron’s primary LO testbed. Maj. David Imig piloted the airplane’s 1,000th flight on July 12, 1994. Following upgrades in March 1997, this airplane was used for paint-endurance testing. In 1998, Ship 783 became the first Nighthawk modified in the Single Configuration Fleet program. A four-month test series evaluated an optimized radar-absorbent coating to improve maintainability and minimize RCS. In 1999, Scorpion 4 was used primarily for pilot proficiency and training, and also served to test a new environmentally compliant low-volatile-organic-compound paint.
To support operational test and evaluation tactics development, as well as a Navy-Air Force Warfighter Talks conference held at Edwards in April 2004, the airplane was painted overall in a two-tone grey camouflage scheme. Scorpion 4 was retired in March 2007 with 2,464.6 total flight hours.
To ready 783 for public display, members of the 410th FLTS removed all radar-absorbent coatings and structures as well as classified equipment, and then fabricated replacements using unclassified materials. The seven-month effort was conducted entirely by volunteers, and only when such activity did not conflict with squadron test operations.
In 2008, Scorpion 4 was placed on outdoor public display at the Blackbird Airpark in Palmdale, an annex of the Air Force Flight Test Museum. Within four years, the condition of the aircraft was beginning to deteriorate due to the hash conditions of the Antelope Valley: intense sunlight, extremely hot temperatures in summer and extreme cold in winter, plus almost constant winds that scoured the airplane with abrasive desert sand. Museum management decided, therefore, to bring the aircraft to Edwards for restoration.
On the night of June 7, 2012, museum staff and volunteers towed the YF-117A some 35 miles under cover of night in order to avoid interfering with local and base traffic. The journey took more than eight hours. Since then, Scorpion 4 has been stored inside a hangar facility where museum volunteers undertook the task of restoring this historic aircraft so that it might one day be displayed in the Air Force Flight Test Museum’s new building, to be located outside the Edwards AFB West Gate and accessible to the general public.
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