The Air Force announced last week they will be retiring the first airplane in their inventory to offer radar-evading stealth technology, the Lockheed F-117 Nighthawk.  Often referred to as the "Stealth Fighter" (fighter is really a misnomer, as the aircraft was primarily used as an attack plane to drop bombs, not engage in air-to-air combat with other aircraft), it was the first operational combat aircraft to use special shapes and materials to disperse radar signals that hit the aircraft. The aircraft, being subsonic, relied on this advanced technology, instead of the previous method of high speed, low level flight, to evade enemy radar. The technology worked, as only one F-117 was lost as a result of direct enemy fire in over 25 years of operation. Much of the radar-evading technology pioneered by the F-117 can be seen in the shape of todays modern Air Force fighters, the Lockheed F-22 and F-35.

I remember early in my career as an aerospace engineer, in the early 80's, I did work with Stencel Aero Engineering out of Asheville, NC, who designed and manufactured the ejection seat for the U.S. Marines AV-8B Harrier. Some of the engineers there told me about a request Stencel received in the late 70's from Lockheed inquiring about the performance capabilities of their ejection seat. Lockheed sent Stencel a basic drawing of a three-dimensional cube and asked if their ejection seat would fit inside that cube. When informed that it would, Lockheed ordered several seats. The Stencel engineers said they would be happy to help install it in the unnamed Lockheed aircraft, but Lockheed said no thanks, we'll do that ourselves, thank you very much. So Stencel sent along detailed installation instructions with the seats to Lockheed. They never knew what type of aircraft their seats were being installed in, and sort of forgot about them until a couple years later when they received one of their seats back, and it had obviously been ejected. Along with the seat was a note from Lockheed indicating that the seat may have malfunctioned, because even though the pilot survived the ejection, he had been injured.  When the Stencel engineers inspected the ejected seat, they determined that it had not been installed correctly in the cockpit. A part of the seat that helps stabilize it as it exits the cockpit had not been connected properly. They sent their report to Lockheed, and didn't hear anything more. It wasn't until the stealth fighter program was declassified in the late 1980s that Stencel found out their seats had been used in some of the early prototype stealth fighters, several of which crashed during the test program. The program was so secret that Lockheed couldn't tell many of their suppliers what their equipment was being used for.  Once the F-117 went into production, the aircraft used the USAF standard ejection seat, the ACESII.

Finally, I recall a trip to the Naval Weapons Center, in China Lake, CA in the summer of 1986. I was helping with testing of a Navy ejection seat at the high speed rocket test track at China Lake at the time. Engineers there were talking about the recent crash of a secret plane in the Sierra mountain range just to the west of China Lake one night in early July. They said that the Air Force quickly arrived on the scene and closed off the area in the mountains where the plane went down. Local fire fighters were called in to help extinguish the small fire that had erupted at the crash site. Some of the firefighters described how there was no discernible aircraft shape at the crash site, but they did notice small pieces of material that appeared to be some type of composite material, not the usual aluminum alloys most military aircraft were constructed of. They also said that they were all searched by the Air Force security guys as they left the crash site to insure they weren't trying to sneak out any pieces of the wreckage. It was only several years later when the F-117 program was declassified that people learned that this was a crash of one of the early operational stealth fighters. In 1986, F-117 flights were still being made only at night time so prying eyes could not get good pictures of the shape of the aircraft. The F-117 was based out of a secret base in Nevada, but often times their missions would take them to the huge, remote military test ranges to the west in California, some near China Lake. It was determined later that this crash, in which the pilot did not survive, was the result of the pilot fatigue and becoming disoriented on a dark night and literally flying into the mountains.