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F-22 RAPTOR STRUGGLES TO MEET TARGETS

It should have been a merry Christmas for all those involved in the F-22 programme, but instead the festive season and the start of the new year turned out to be a hard slog. Because some critical test criteria explicitly required by Congress had not yet been satisfied, the US Department of Defense put back the planned 21 December meeting of the Defense Acquisition Board, first to 3 January and then to still further down the road.

Now the new government under President George W. Bush, incumbent since 20 January, will have to turn his attention to LRIP approval for the stealth fighter, already delayed by a year. The change of government will not exactly make matters any easier, as it means that manufacturer Lockheed Martin and the US Air Force will now have to brief a new set of decision-makers on the programme details.

Although it seems likely that total military expenditure will increase under Bush and his defense minister Donald Rumsfeld, the Raptor is unlikely to be given a blank cheque by the new administration. There are too many critical voices for this. In particular, the General Accounting Office (GAO) issued another warning last year that the costs could significantly exceed the strict limits imposed by Congress.

The GAO, acting on behalf of Congress, pointed out that both the Air Force estimate of the cost of building 339 aircraft ($40.8 billion) and the Pentagon's forecast ($48.6 billion) exceed the $39.8 billion limit. The discrepancy of almost 20% arises from different calculation methods, but above all from different estimates as to whether planned cost reductions of no less than $21 billion can be implemented or not.

Sample data has shown, according to the GAO, that a significant part of the savings programme is not actually under the control of the Air Force or the manufacturers. For example, orders running over a number of years require approval from Congress. One legitimate way out would of course be to reduce the number of aircraft to be purchased, but the USAF is already complaining that it will need additional F-22's in order to equip the squadrons for all its expeditionary air forces.

In order to remain within the limits, the programme management team in Wright Patterson AFB, Ohio is resorting to all the tricks in the book. The latest idea is initially to ramp up the production rate more slowly in order to put money released into optimising production processes, which will make later aircraft cheaper to manufacture.

Moreover, there are cost limits not just for production, but also for development and testing ($20.4 billion at 2000 prices). Here, costs are currently estimated to be around $200 million over budget. There are therefore apparently plans to initially forego qualification of certain equipment (helmet-mounted sight and AIM-9X Sidewinder). But even so the F-22 would still be able to satisfy its operational requirements according to the programme office.

As well as the concerns about the costs, the test programme was causing headaches last year as well. Problems with fine cracks in the cockpit canopies, for example, led to the Raptor being grounded for almost four weeks in the spring. Then prototypes 4003 to 4006 were up to a year late in achieving flying condition. This meant that satisfying the dozen test items set by Congress became a race against time. Three of them the F-22 team only managed to clear in December and January 2001, while another two were still outstanding at the time of going to press (see box).

All this suggests that the Raptor programme will continue to be an uphill struggle for Lockheed Martin and the Air Force. However, cancellation of the air-dominance fighter, as was menacingly hanging in the air in the middle of 1999, is very unlikely. Again, a delay in the decision to release $2.1 billion for the first ten production aircraft is currently not yet critical. As a precaution, the budget for 2001 allows $350 million to cover delay-free continuation of the programme to the end of March.

Raptor tests item by item

In response to pressure from the US Congress, the Pentagon (Undersecretary of Defense for Acquisition, Technology and Logistics) imposed 15 criteria which had to be satisfied before the first 10 serial production Raptors could be ordered. These concerned both the flight test programme and also ground testing and development milestones for the highly complex software. Specifically, the milestones are as follows:

• Prototype 4003 took off on 6 March 2000 with Chuck Killberg on its maiden flight. On 15 March it was transferred to Edwards AFB, where, however, it was required first of all to undergo various ground tests since, from Rapture 4003 onwards, the structure has been reinforced and hence has different vibration characteristics. This had become necessary if the F-22 was to be cleared for 9g manoeuvres.
• The first AIM-9 Sidewinder was launched from the side weapons bay of the F-22 (Raptor 4002) on 25 July, in horizontal flight at Mach 0.7 and at 6,100m (20,000ft) altitude. Chuck Killberg was in the cockpit. The next firing of a Sidewinder in December was performed at a high angle of attack.
  
• The tests of flight characteristics at high angles of attack with weapon bay doors open were completed by 22 August. Jon Beesley carried out the first trials in Raptor 2002. According to Beesley, the results were "outstandingly good".
• The design review of the avionics software version 3.1, for which Boeing is responsible, was completed by 30 September.
• On 24 October an AIM-120C AMRAAM was successfully launched for the first time by the Combined Test Force over China Lake, California. The test missile was released by Lieutenant Colonel David Nelson at Mach 0.9 at an altitude of 4,725 m from Raptor 4002. The launch sequence lasted scarcely more than one second. The Raptor is scheduled to launch a total of 60 AMRAAMs during tests.
• The first stage of endurance testing of the Pratt & Whitney F119 engine commenced at the beginning of May and was completed on 31 October 2000. 2,168 total accumulated cycles were accomplished, equivalent to half the time between two major overhauls or around five years in service.
• The complete review of the production configuration for the F-22 airframe was completed by Lockheed Martin and Boeing, as its subcontractor, on 8 November 2000.
• Prototype 4008 received its wings and empennage on 11 November as per specification.
• Prototype 4004, the first to be fitted with a full avionics suite flew for the first time on 15 November in Marietta. The test pilot was Bret Luedke. Prototype 4004 had already rolled out of the hangar in June, but problems occurred during ground testing when the cooling system for the avionics failed to function as expected. Software modifications were required to fix this. The aircraft had initially been fitted with software version 1.2.
• The static tests which were necessary to airframe 3999 to extend the permitted flight envelope of the prototypes were completed on 21 December. 19 primary criteria and numerous local loading values up to 150% of the expected load during flight had to be demonstrated. There were problems in November when the testing stand was damaged.
• Fatigue testing of test airframe 4000 commenced on 21 December in Marietta. By November 2001, 8,000 flying hours should have been simulated, and 24,000 hours by 2003.
• After snow storms and cold weather had necessitated a delay, prototype 4005 took off for its first flight in Marietta on 5 January 2001, piloted by Boeing test pilot Randy Neville. This aircraft is the first one to have Block 3 software, which permits optimal processing of the sensor data and weapons deployment as well as electronic warfare functionality. The programs had previously been tested in a specially equipped Boeing 757.
• Radar cross-section testing of a latest-build aircraft remained to be completed at the time of going to press. This will be carried out by Raptor 4004 in Edwards AFB.
• The maiden flight of prototype 4006 was expected to take place in January.

From page 64 of FLUG REVUE 3/2001