Lockheed Martin plans to upgrade the US Air Force's fleet of F-117A strike aircraft to a common low observable (LO) configuration which it says will dramatically reduce maintenance costs and improve operability.

The Single Configuration Fleet improvement programme will begin in October 1999 when the first of up to 53 F-117As due for the upgrade arrives for periodic maintenance at Lockheed Martin's Skunk Works in California. "The plan is that the whole fleet will go through, but it also depends on funding available," says F-117 programme manager Ross Reynolds.

Key elements of the improvement effort include standardisation to one leading edge configuration (from five), and spray coating of the entire fleet with the same radar absorbent material (RAM), using a common quick cure process.

Of the current fleet, 33 have been sheet coated and the balance spray coated. The sealing and gaps around the canopy and forward looking infrared screen will also be improved. Together with the introduction of other improvements, such as "zip strips" (removable strip seals for panel access), Lockheed Martin says the programme will reduce the "number of RAM products on the aircraft by 30%", improve environmental control and cut maintenance costs by 65%.

The upgrade will be performed by the Skunk Works, which took over logistic support of the F-117A on 1 October under an innovative $1.8 billion deal with the USAF. Under the programme, dubbed the Total System Performance Responsibility (TSPR), the Skunk Works is providing engineering technical support, spare parts administration, technical data and field support at the 49th Fighter Wing base at Holloman AFB, New Mexico. Lockheed Martin says that substantial cost savings are expected to result from the TSPR initiative, which will run for five years with a possible three-year extension beyond that.

The beginning of the upgrade work is also expected to coincide with the completion of a seven- year Ring Laser Gyro Navigation Improvement Programme (RNIP+) for the F-117A fleet, which is "about two-thirds of the way through", says Reynolds.

The effort covers the replacement of the original Honeywell SPN-GEANS inertial navigation system with the Honeywell H-423/E laser inertial navigation system and the integration of a Rockwell Collins global positioning system with LO antennas. The RNIP+ includes a weapon system computer upgrade.

Source: Flight International