Flight Test

25 March 1991 saw the completion of a move for F-117 flight test operations from Area 51 to Palmdale. Activity from the new base continued at a brisk pace with Aircraft ’831, flown by Lt Col Chris Seat, completing Det. S’s first flight from Palmdale the day before. However, the first Senior Trend test sortie from Palmdale was a weapons evaluations flight, flown in Aircraft ’784 by Jim Thomas on 23 April 1992.

On the 23 October 1991, a low observability communi­cations study was authorised to identify methods of maintaining communications with an F-117 once it had ‘stealthed-up’ and retracted all its antennas. The study was completed in February 1992, and on 31 August that same year, Jim Thomas flew Aircraft ’783 on its first low observability antenna evaluation sortie. The test program lasted for two months, during which rime the ‘stealthy antenna’, located on the aircraft’s underside, was thoroughly evaluated. Following submission of a final report on 13 November 1992, the go-ahead for full scale development of the system was received on 12 May 1993; work commenced four months later, on 16 September, to upgrade the fleet.

Above left On 8 July 1992, Tonopah was deactivated and the 37th moved its F-l 17s to Holloman AFB, New Mexico. (USAF)

Above With the move from Tonopah to Holloman, came a redesignation and the 37th FW became the 49th FW. Aircraft ‘816 of the 7th FS is seen overflying the F-117 barns at Holloman. (USAF)

Below Members of the 9th FS, together with their 18 F-l 17s, form-up behind their boss at that time, Lt Col Greg Feest. (Col Greg Feest)

On 10 October 1994, The Ring Laser Gyro Navigation Improvement Program (RNIP), commenced. Initially designed to evaluate the proposed replacement of SPN – GEANS by the Honeywell H-423 Ring Laser Gyro, the program was subsequently broadened (based on earlier successes achieved by the low observability communica­tion antenna program), to include the addition of a Global Positioning System (GPS). A ‘dry bay’ was creat­ed, by forming a recess in the fuselage fuel tank, on the upper surface of Aircraft ‘784. Into this was located a stealthy antenna, capable of receiving the relevant satellite generated data. The first RNIP flight occurred on 12 December 1994, and the enhanced accuracy was immedi­ately apparent. This improvement package was incorporated into the entire F-l 17 fleet. Other benefits offered by the antenna were also exploited, giving rise, in December 1997, to the IRRCA, or Integrated real-time information into the cockpit/Real-time information out of the cockpit, for Combat Aircraft flight test project. Now there’s an acronym to test your friends with! By 30 June 1998, the first phase of the program, "real-time informa­tion into the cockpit’ had been successfully demonstrated. Phase two, ‘real-time information out of the cockpit’ began in 1999.

At the heart of IRRCA is the integration of a real-time symmetric multiprocesser, facilitating 1.2 billion instruc­tions per second. As the F-117A receives threat updates from satellite broadcasts, a moving map displays new threats and the processor automatically evaluates the situ­ation. Should analysis of the threat determine that the aircraft is in jeopardy, the processor re-plans the route and display’s the option on a new colour liquid crystal diode multi-function display. Decision criteria used in the

Above Another mission begins as this extraordinary geometric study prepares to taxi from its barn. (USAF)

Right An AT-38B of the 7th FS on business at Palmdale. Note the three F-117s on the tail-band. (Paul Crickmore)

Below right F-l 17 test pilot Jim ‘JB’ Brown of the 410th Flight Test Squadron, based at Palmdale, readies 784 for another IRRCA test flight. (Paul Crickmore)

proposed re-route includes threat exposure, flying time and landing fuel. The pilot can then accept or reject the proposed option. In addition to mission information, text and images also update the pilot on key events and weather. Evaluations carried out by the 410 Test Squadron at Palmdale indicate that the F-117A is capable of reacting to mission updates or target changes and pop­up threats while still remaining in a stealth configuration.

In early July 1998, Jim ‘JB’ Brown, lead IRRCA test pilot, flew a simulated combat mission in the dedicated testbed, aircraft ’784. During the course of the sortie, a geostationary satellite transmitted a series of encrypted messages to the aircraft via its low-observable communi­cations antenna. These messages included threat updates, mission updates, text information and alternative target imagery. Mission changes provided information for the real-time symmetric multi-processor to re-plan the mission to an alternative target. This was followed by a text message and photos of the alternative target, which enabled ‘JB’ to verify the processor’s planning results and study target details prior to acquisition and attack.

Other Evaluations

Over the years other parties have evaluated the F-117A’s capabilities. The first of these being the United States Navy. Two Navy pilots flew the aircraft on eight occa­sions, during each flight they were chased by an instructor pilot in a T-38. Details of their flight log show that this was a serious evaluation:
Pilot	Date	А/С SERIAL	Time	Duration
Linn	23.10.84	’783	08:38	1.3 hours
Grubbs	23.10.84	’782	13:36	1.4 hours
Linn	24.10.84	’782	13:18	1.6 hours
Linn	25.10.84	’783	08:20	1.6 hours
Grubbs	25.10.84	’783	13:05	1.3 hours
Linn	25.10.84	’782	13:18	1.3 hours
Grubbs	29.10.84	’782	12:33	1.5 hours
Grubbs	31.10.84	’782	13:15	1.4 hours
			Total	11.4 hours

In conclusion of the trials, Lt Cmdr Kenny Linn recalls: “We conducted a thorough performance review, and eval­uated the F-117A for suitability in the carrier environment. Unremarkably, it was not suitable at that time for CV use, although it had quite nice handling characteristics in the pattern, landing speeds were too high, and the sink rate limitations were too low. The F – 117A had not been built as a CV aircraft, and was not going to turn into one overnight!”

Following the collapse of European Communism, few countries were better placed to successfully complete the transition into a free market economy and democracy than Yugoslavia. However, nationalism, spurred on by the Milosevic regime have conspired to drag the region into ‘a new dark age’. The planning and implementation by

Serbia of ‘Operation Horeshoe’ – the systematic ‘ethnic cleansing – deportation and genocide – of the Kosovar Albanians, haas once again taken ships and aircraft of NATO to war. At approximately 20:38 (local) on Saturday, 27 March 1999, F-117A, ‘806, of the 8th FS, flown by Major Dale Zclco, crashed forty miles from Belgrade whilst participating in Operation Allied Force. Although speculation surrounding the loss of this aircraft is rife, nothing has been officially released at the time of writing, other than the fact that Zelco was safely extract­ed from the area bv a combat rescue team.

below Stealth technology is not something reserved solely for military aircraft: witness the Skunk Work’s Sea Shadow.

(Lockheed Martin) ,

Above Years of stealth technology were designed into the low visibility of the Lockheed F-22 Raptor. Without black world, no F-22, or at least, many more years of R&D. (Lockheed Martin)