The McDonnell Douglas C-17 is facing its toughest test so far.


It is make-or-break time for the McDonnell Douglas (MDC) C-17. The future of the military transport, and that of the US Air Force's global heavy-lift capability, hinges on the outcome of two pivotal events in July and August.

The first event is seen by most, including MDC, as the acid test. It involves a full-scale, 30-day, USAF evaluation, beginning on 7 July, during which 12 C-17s will be operated at full stretch under wartime and peace conditions. The second, and, some would argue, more politically significant event, will be the August submission of an MDC proposal to cut the C-17's unit price down to at least $212 million.

The results of these events, together with the findings of several other airlift studies, will be boiled down during a gruelling programme review by the Pentagon's Defense Acquisition Board (DAB) in November. The "Milestone IIIB" DAB decision, as the review is known, will determine how many more, if any, C-17s will be bought. The DAB will also decide whether to supplement the C-17 with other non-developmental airlift aircraft (NDAA), such as a revamped Lockheed Martin C-5D or a military variant of the Boeing 747-400F.

Led by the US under secretary for defence and acquisition, Paul Kiminski, the DAB is therefore faced with two basic alternatives: to buy 80 more C-17s to complete the USAF's planned fleet of 120, or to determine a mix of C-17s and newly built C-5Ds, or 747-400Fs.

Boeing, for one, has presented compelling arguments for a mixed purchase of C-17s and 747s, stating that the vast bulk of material delivered for the 1991 Operation Desert Storm, for example, was palletised and did not require a specialised military transport. The company has privately expressed the feeling, however, that the NDAA exercise could easily be interpreted as a "stalking horse" to force MDC into urgent action. Boeing has been reassured by the Pentagon that the NDAA is "for real" and points to $103 million voted for NDAA studies by Congress as evidence.


Startling turnaround

With or without the spectre of a stalking horse, the turnaround of MDC's performance has been startling. The beginning of the transformation dates from the unusual Omnibus settlement reached between MDC and the US Department of Defense in January 1994. The agreement smoothed the increasingly troubled relationship which existed between MDC and the USAF and essentially provided a breathing space for both sides to re-group. It covered the limited purchase of the first 40 aircraft, but deferred to November 1995 a final decision on the balance of the $20 billion fleet.

"We're pretty much on probation and everything rides on our performance between late 1993 [when the Omnibus settlement took shape] and the DAB review," says MDC C-17 programme manager Don Kozlowski. "We have to demonstrate we can manage the programme and provide a quality product at an affordable price. In the end, we're just hopeful that we'll get a fair shot at 120."

Kozlowski confidently adds that, "...although the C-17's had lots of problems in its history, it's not difficult to show these improvements can be made. The beauty of this programme is that the design is good and solid. The structural integrity is as good as any we've built and, although we have had a wing failure, it was a design fault and we fixed it. Now, development testing is complete and the certified product is working as advertised."

Kozlowski has two immediate priorities: to keep building up the improvements within the Long Beach-based programme, and to give maximum support to ensure that the 30-day exercise is as smooth as possible.

"Now we have to demonstrate that the product is under control and concurrently tackle the affordability issue," he says. He aims to get the unit price down from $300 million at the beginning of 1995 to $212 million (in fiscal year 1995 dollars), or less, for the remaining buy-out of the programme (from aircraft 33 to 120). He says that costs are being reduced rapidly, and he expects the price to fall further.

To combat the cost, MDC has marshalled its suppliers to quote prices for the entire production span of the transport assuming a positive DAB outcome. "Normally, we'd go after this one year at a time, but, this way, we're getting proposals for the entire $20 billion procurement package between now and 2004," Kozlowski argues.

MDC's suppliers, which contribute 80% of the programme cost, have reacted "....quite well, and so far most have hit the target", says Kozlowski, who aims to offer the USAF the revised cost package on 1 August. MDC is also working hard to cut out costs within its own organisation, as well as promoting more efficient manufacturing.

Under the terms of the Omnibus agreement, MDC has committed around $100 million to improving its manufacturing processes. This is being achieved at several levels throughout the C-17 assembly process and ranges from cost reduction at the supplier and inter-company work level, through re-designing for easier manufacture to moving parts manufacturing to more cost-effective locations within MDC.

Early improvements have already reaped significant savings. MDC says that, over the working year, from aircraft 11 delivered in April 1994, to P-19 delivered in April 1995, assembly hours were reduced by 28%. Rework and repair hours, a significant contributor to the earlier cost and time over-runs which plagued the C-17, were cut by 48% over the same period.

The result, as MDC points out, has been a reduction in the average cost of the aircraft by 11%, or $29 million. In consort with the manufacturing changes are improvements in quality and schedule control. "We are delivering aircraft early. The last eight aircraft, up to the 20th, have all been delivered ahead of schedule," says MDC.

MDC aims to make further reductions through more changes in the construction of each aircraft. "I would really like to see target costs get lower, and we've been doing some analysis to see how we can do that. I've been asking, 'can I change processes, the amount of automation and even the design?' The answer is 'yes' to all of those," says Kozlowski.


Halving assembly time

A major effort is being made to use Omnibus funds to change manufacturing and assembly with the aim of halving the man-hours needed to fabricate each C-17. "We've got something like 150 projects at the shop-floor level and about another 100 in the conceptual stages," Kozlowski says. Examples of these include the use of a new machined landing-gear-pod bulkhead to replace the present built-up assembly. This is expected to save 2,100 assembly hours per aircraft and 8,400 installation hours. It will also eliminate 16,000 fasteners and 1,500 parts.

The company is also using high-speed machining for a new unitary ramp-bulkhead to replace the current built-up assembly. The move eliminates more than 700 parts and 11,000 fasteners, cutting more than 1,100 assembly hours. "We are also studying a new, low-cost nacelle design that will reduce aircraft weight by 1,350kg and would save $500 million over the remaining production run. It would also shave $250 million in support costs after the aircraft is delivered," says MDC.

"The projects cover everything from bracket design to major sub-assembly," says Kozlowski, who cites self-sealing fasteners, a one-piece lower-wing skin, revised horizontal trailing edge, and a wingtip redesign as examples of projects under way.

While these changes keep MDC busy, the most immediate concern is with preparations for the 30-day reliability, maintainability and availability evaluation (RM&AE). During the test, 12 Charleston AFB, South Carolina-based C-17s will be flown for more than 2,100h and seven airfields will be used. The first 23 days of the exercise will simulate peace-time conditions with standard airlift operations from Charleston AFB and Dover AFB, Delaware, to RAF Mildenhall in the UK. Additionally, joint US Army and Air Force training missions will be flown at Pope AFB, North Carolina.

The 23-day first phase will also see air refuelling, airdrop and small austere landing training missions at Charleston and its nearby auxiliary airfield.

The last seven days of the RM&AE will see the aircraft and its support system pushed to the limit during a swift ramp-up to wartime conditions simulating a multi-regional scenario. The week will also include two surge days to simulate the beginning of a conflict when large amounts of equipment need transporting to forward operating bases. During the surge period, the fleet is scheduled to average nearly 16 flying hours per aircraft per day.

For this phase of the evaluation, equipment will be flown from Charleston AFB, Fort Bragg, California, and Pope AFB to RAF Mildenhall, Barstow-Daggett, California, and Bicycle Lake Airfield at the nearby National Training Center in Fort Irwin.

All flights will be operated by crews from the 437th and 315th Airlift Wings, the only units to have received the C-17 to date. As in three previous readiness reviews, the RM&AE has been designed to emphasise both the tactical and strategic capabilities of the C-17. Long-range sorties will be coupled with short-field landings and 30min turnarounds, during which the engines are not turned off.

"It's not just one aircraft, it's 12. It's not just a few flights, it's 2,100h. It's a lot more than simply turning the equipment on and seeing how long it lasts," says Kozlowski.

"The RM&AE can be seen as a snapshot of the entire life of the aircraft," says Lt Col Dale Shrader, director of planning for the July exercise. "It'll fly every type of mission from special assignments and strategic airlift to joint airdrop-training missions and tactical resupply. In effect, we'll be crunching 30 years into 30 days."

A total of 25 specific missions has been formulated for the event. "We want to do a fair evaluation, so we will create an environment in which the aircraft is the focus. We want to give the aircraft the opportunity to perform....or not perform, whatever the outcome," says Shrader. The USAF is therefore working hard before the exercise begins, to eradicate any outside reasons which may contribute to a mission failure. "We're trying to isolate cause and effect strictly to the aircraft," he adds.


Mature fleet condition

The fact that the fleet is so young will also be taken into account during the tests. "By the time the test begins in July, we'll have around 13,000h on the fleet, yet we'll be aiming at a mature fleet condition, which is normally measured at 100,000h," says Kozlowski.

Raising performance to achieve levels normally found on something ten times as mature has not been easy, says Kozlowski. "We've worked the hell out of it with both ourselves and our suppliers. We alerted them to just how serious this was. You can have the world's best design, but one failure can kill you. We could not afford to have an Achilles heel in the system," he says.

Some of the problems which cropped up in the three earlier readiness reviews have therefore received special attention in the build-up to the RM&AE. Most of the aircraft-related issues were concerned with failures, or glitches with on-board computers, software, wheels, hydraulic leaks and replenishment of nitrogen.

"We've fixed up most of the obvious failure items," says Kozlowski. Many were related to the aircraft's four major embedded computer systems which support 57 digital line-replaceable units (LRUs). The major systems include the mission computer, warning and caution, integrated radio management and flight control. Data from related LRUs are connected via 1553B and ARINC 429 databuses which together provide a centralised fault-reporting system.

"We had lots of software to improve [more than 970,000 lines of code], including the built-in test for each LRU. Most of these were in the form of programmable, read-only, memory, almost firmware, so we have been recycling LRUs," says Kozlowski. The improved LRUs have reduced the number of nuisance messages and reduced failure modes, he adds


Significant improvement.

Another significant area of improvement has been in tyre servicing. "This is a STOL [short take-off and landing] aircraft with routine full-stop landings within 1,500ft [450m] and turning around in 90ft. The tyres have been wearing out and we need a quick time change. We're literally getting into the same things the racing-car guys are. You want a quick turn-around in the pits".

Kozlowski's target is 15min. "At the moment, it's 35 to 40 min. We have a 2h 15min turnaround time on the ground and we want them to be able to do the tyre change well within that." MDC is adapting a portable wheel-changing dolly, to shorten the change time, and is trying out the design on the aircraft's unconventional main gear, each of which consists of two legs in tandem with three wheels on each leg.

"We can also service the landing-gear struts with OBIGGS [on-board inert-gas generators], and re-charge our own nitrogen bottles on the aircraft," says Kozlowski. Two hydraulically operated stabiliser struts, which support the C-17 when loading vehicles weighing more than 29,500kg, can also be used to jack the aircraft for a tyre change. "These types of things will be very valuable during the test," Kozlowski says.

In the end, the C-17's performance will be measured by several major metrics. The main parameter will be utilisation. "The flying time per aircraft has taken on a dramatic significance," says Kozlowski. "We'll be shooting for 15-6h per day per aircraft. It will be like running a full-scale airline under combat conditions."

Despatch reliability is another important metric. Air Mobility Command's requirement is for departure within 14 and 15min of the scheduled time, and MDC hopes that the RM&AE will see despatch-reliability rates of around 85%. Another measurement will be the fully mission-capable (FMC) rate. "Almost all the aircraft are partially mission capable, but on this exercise we'll also be judged on the FMC rate," Kozlowski says. In this area, MDC is looking for results around 75%.

Another critical parameter is mean time between maintenance. "That's when you can't fly until you've fixed it," explains Kozlowski. "We're essentially beating that figure by roughly three times." MDC attributes this to the easy access for LRU replacement, and quick-access-panel architecture for valves and hydraulics. "Fundamentally, it doesn't break very often and, when it does, it's easy to fix," says the company.

After the bitter beginnings of the C-17 programme, the $1 billion cost-overruns and technical problems, the RM&AE is seen as a true "proof-of-the-pudding" test of the claimed improvements. "Up to this point there's been a lot of speculation as to whether the C-17 meets the specification. Now we have the opportunity to put objective figures to that," says Shrader.

"We believe MDC has finally turned the corner and is, firstly, on time and, secondly, making them with sufficient quality that we're able to put them into service immediately," he adds. "As far as final planned numbers are concerned, the USAF's official position is 120. Me? I'd like to see 3,000."

Source: Flight International