GRAHAM WARWICK / WASHINGTON DC
After a series of hitches and delays, the US Department of Defense will imminently decide if the F/A-22 stealth fighter has developed sufficiently to begin operational tests
After years of frustrating delays, the Lockheed Martin/Boeing F/A-22 Raptor programme appears to be gaining momentum. Aircraft are being delivered to operational testers, the first low-rate initial production F/A-22 will arrive at the US Air Force's training squadron this month, and a year from now the first combat unit is to begin receiving Raptors. But several objectives still must be accomplished before the F/A-22 can enter operational testing in November, and the programme's record of staying on track is not great.
Later this month or early next, the DoD's Defence Acquisition Board (DAB) will decide whether the F/A-22 is ready to enter operational testing. The US Air Force is "cautiously optimistic" the Raptor will be ready, says Brig Gen Mark Welsh, director global power programmes. Even if the F/A-22 does pass the DAB, formal initial operational test and evaluation (IOT&E) will not begin until February or March, as it is taking longer than expected to modify enough aircraft to production standard to support realistic four-ship testing.
A year ago it did not seem likely the F/A-22 would make it this far. A US Air Force cost review estimated development was $690 million over budget because of flight-test delays caused by fin buffet and avionics instability. In December, the USAF increased the budget by $876 million, stretched development by 20 months and delayed the start of IOT&E to October this year. Rather than ask for more money, the air force took $763 million from the production budget to help pay for the development overrun, reducing planned procurement to 276 aircraft.
In an action with the hallmark of a final push to get the F/A-22 on track, the programme leadership at Lockheed Martin and the US Air Force was replaced. Senior Pentagon officials publicly stated that any further delays and overruns could lead to cancellation of the USAF's highest-priority programme. However real the threat, it seems to be having the desired effect. The programme has made steady progress since the beginning of the year, but it has not been easy.
Course correction
In July, the air force was forced to make yet another course correction. Instead of beginning in October, operational testing is to be delayed and split into two phases. The first, called operational test and evaluation (OT&E) Phase 1 is to begin in November using just two aircraft. Formal IOT&E, which requires five production-standard F/A-22s, will now start in February. Welsh believes the new schedule will still support a decision on full-rate production in November 2004, and the USAF is sticking to its initial operational capability (IOC) date of December 2005. "The full-rate production decision is more of a constraint than IOC," he says.
As an aircraft, the stealthy F/A-22 is meeting or exceeding its key performance parameters (KPPs), Welsh says. Radar cross-section has been verified on three airframes and is better than requirement. Supercruise performance - supersonic cruise speed without afterburner - is Mach 1.68, 12% above target. Acceleration, payload and combat radius exceed requirements, while the thrust-vectoring Raptor is meeting its manoeuvrability goal. Detection range of the Northrop Grumman APG-77 active-array radar beats expectations by 5%.
Three KPPs define supportability metrics the Raptor is required to meet at the 100,000 flight-hour mark. As the 17 aircraft flown so far have between them logged just over 4,000h, the USAF's estimate that the F/A-22 is also meeting its airlift support, sortie generation rate and mean time between maintenance goals is based on analysis.
The Raptor was missing its airlift support goal, expressed in Lockheed C-141 equivalents, based on assumptions about the amount of low-observability (LO) maintenance required during a 30-day combat deployment. "We are meeting the metric now," says Welsh. "We did not have data on LO maintenance, so we assumed the worst case when developing the model. Now we know what LO maintenance can be deferred."
Fin buffet fix
The one airframe issue that contributed most to the delays, fin buffet, has been resolved, says Welsh. The solution, which involves changing the rear spar from composite to titanium, has eliminated buffet above 10,000ft (3,000m). Apart from testing to clear the fin fix below 10,000ft, expected this month, flight-envelope clearance for IOT&E is complete, he says.
The F/A-22 also works well as a weapon system - when it works. Avionics stability has emerged as the programme's biggest issue, and the need to repeatedly restart software has frustrated flight testing of the highly integrated avionics. At its worst, avionics shutdowns averaged one every 1.3h and software was unavailable for 14min out of every 2.5h sortie.
There are several classes of instability: Type 1 is a reboot of the complete system, which takes 4-9min; Type 2 is a subsystem reset, which can take 3-30s; Type 3 and 4 are manual and automatic resets of non-essential subsystems, "which you don't do in the heat of battle", says Welsh; Type 5 is a hardware failure. The frequency of restarts is measured as mean time between instability events (MTBIE).
Welsh says 93% of the code is stable, but the 7% still being worked on integrates the sensor data and enables the F/A-22 to do its mission. "The problem was the integration of functionality, so we stepped back to the baseline functionality - that is 93% - and added capability a piece at a time. Progress has been relatively dramatic," he says.
Start-up performance, which should be 100%, was 65% in February; by August it was 75%. In February, MTBIE was 1.9h for Type I instabilities and 1.3h for Type 1 and 2; by August these had improved to 25h and 9.8h, respectively. "We focused on Type 1 first, to find and fix the problems. Now we shift to Type 2," Welsh says. "And we are not just fixing problems; we are adding capability."
Software unavailability is down to 2min per mission. "With more recent versions it is a different world. The frustrations are gone and pilots can get on with doing their jobs, but 2min is not good enough," says Welsh. Approval to enter operational testing will require continued progress with avionics stability. "The DAB will take another look in September/October, and we need to get the trends as high a possible. I'm cautiously optimistic."
The DAB will use a new metric to assess progress - mean time between avionics anomaly (MTBAA) - which includes Type 1 and 2 instabilities, some Type 3 and Type 5. "Whether it's hardware or software, the pilot doesn't care," says Welsh, adding that MTBAA is a tougher standard than MTBIE.
Full-rate production
The new metric is intended to give the DAB an indication of whether IOT&E can be completed in 31 weeks to support a full-rate production decision in November next year. The DAB has not set a number, but an MTBAA of 5-7h is required for moderate to low risk of not completing operational testing in time, he says.
Even if the F/A-22 is approved to enter operational testing, the US Air Force faces a continuing battle to justify the high cost of the aircraft. Cost has been the key issue through all the bewildering twists and turns the programme has taken since the USAF began the drive to replace its Boeing F-15 air-superiority fighter in the 1980s.
In 1985, when Lockheed and Northrop won contracts to demonstrate the YF-22 and YF-23 Advanced Tactical Fighter (ATF) prototypes, respectively, the USAF planned to buy 750 aircraft at a rate of 72 a year, with production beginning in 1992.
Cost spiral
By 1991, when Lockheed's F-22, powered by Pratt & Whitney's F119 engine, won the ATF contest, procurement had been reduced to 648 aircraft and production delayed to 1996 and slowed to 48 a year. It was just the start of a downward slide in numbers that has driven an upward spiral in costs.
The DoD's 1994 Bottom-Up Review reduced procurement to 442 aircraft. Three years later, the Pentagon's Quadrennial Defence Review cut the numbers again, to 339 aircraft, and reduced the production rate to 36 a year. Cutting the programme from 750 aircraft at 72 a year to 339 at 36 a year drove the Raptor's fly-away cost up by more than 50%, the USAF estimates.
But the cuts were not over. In 1999, a delay in approval for low-rate initial production (LRIP) resulted in six aircraft being redesignated production-representative test vehicles (PRTVs) and earmarked for force development evaluation. Production was finally approved in 2001, and the first LRIP F/A-22 will be delivered to the Raptor training squadron at Tyndall AFB, Florida, this month.
In late 2000, it became clear production was going to exceed the cost cap imposed by Congress. As a result, the DoD reduced procurement again, to 297 aircraft, but approved a "buy-to-budget" strategy that allowed the air force to acquire up to 333 F/A-22s if producibility improvement initiatives bore fruit. Then, late last year, the development overruns emerged, and production funds were poached to put the programme back on track.
Now the DoD estimates the air force can afford 270 Raptors. The USAF predicts it can buy 276 - a number it is not happy with - and remains hopeful that production cost reductions and its buy-to-budget strategy will push the eventual total higher. Welsh says the air force has already secured one additional F/A-22 as a result of production cost savings, raising the planned total to 277, but it could lose aircraft if Congress acts on its threat to cut the number procured in fiscal year 2004.
There is one important caveat to these numbers. Both the DoD and USAF estimates assume a production budget of $42.2 billion, which is $5.4 billion above the Congressional cost cap. The Pentagon plans to seek relief from the production cap in the FY2005 budget. If the cap stays, the USAF could end up with as few as 224 F/A-22s, estimates the General Accounting Office - a long-time critic of the programme. This would be far short of the 380-plus Raptors the USAF says it needs.
Whatever the final number, production is gathering pace. The aircraft handed over to Tyndall AFB later this month will be the 18th Raptor, and the sixth this year, with five more to come in 2003. Deliveries are seven months and six aircraft behind schedule, says Welsh, but Lockheed Martin expects to be back on plan by mid-2004. "The leading indications are all in the right direction," he says. "The new leadership at Lockheed Martin has made big changes. They had parts problems, but are down to managing 200 unique parts. This is well within normal requirements, and none are on the critical path."
Tooling in place
Tooling to support full-rate production of 32 aircraft a year is in place and validated, Welsh says. Three LRIP lots totalling 44 F/A-22s have been ordered, and a Congressional vote on whether the US Air Force will get the 22 aircraft it wants in FY2004's Lot 4 is imminent. Plans call for 24 F/A-22s in FY2005 and 28 in FY2006, with the full 32-a-year rate being reached in FY2007. Getting production back on schedule, and the aircraft configuration stable, is crucial to USAF plans to seek approval for cost-saving multi-year procurement beginning with full-rate production.
Deliveries to the first USAF combat squadron, at Langley AFB, Virginia, are to begin late next year, and the F/A-22 is scheduled to be declared operational in December 2005 - 15 years after the programme formally began. Lockheed Martin is under contract to define a spiral development path for the aircraft, focusing on additional air-to-ground capability. At IOC, the F/A-22 will carry JDAM GPS-guided munitions as well as AIM-9 short-range and AIM-120 medium-range air-to-air missiles. AIM-9X and the Small Diameter Bomb are planned for a later spiral.
But that is later. For now, software development continues while the five Raptors required for IOT&E - the last three development F/A-22s and first two PRTVs - are retrofitted with the $2 million fin-buffet fix and 30 other modifications. It remains a close race to get the Raptor ready.
Source: Flight International
