C-17 Aircraft Is 8.2% Overweight, but Douglas Says Cost Is Still on Target

The estimated weight of the Air Force C-17 cargo aircraft under development at McDonnell Douglas has increased by 8.2% over original plans, resulting in the aircraft not meeting one of its contractual performance requirements set by the Pentagon.

But the weight growth, which has been an ongoing concern in the C-17 development, has not forced the program into a financial overrun on its fixed-price contract, according to Douglas C-17 general manager Robert L. Clepper.

The firm’s Douglas Aircraft unit in Long Beach is under contract to develop and later produce the C-17 in a program valued at an estimated $35.4 billion, including future inflation. Douglas will build 210 of the four-engine aircraft by the year 2000.

“We have had steady weight growth,” Clepper said in an interview. “That is not too unusual. Airplanes struggle with weight growth. We have been working hard to hold the line.”

Clepper added, “The worst is behind us. We will meet our specification requirements as we know them today. We are still in negotiation today on one requirement that we will not be able to meet.”

That requirement involves the unfueled ferry range of the aircraft, which was originally set at 4,914 nautical miles but now is likely to be only 4,700 miles.

The reduced ferry range, which refers to the maximum distance the airplane can fly carrying no cargo, has not been a major Air Force concern, however. Since the aircraft can be refueled in flight, the Air Force has been flexible on that requirement, Clepper said.

The other key performance requirement for the aircraft, which calls for flying 167,000 pounds of weapons a distance of 2,400 miles unrefueled, will still be met, he said.

The original goal for C-17 called for an empty weight of 245,000 pounds, but the current estimate is for 265,000 pounds, a 20,000 pound increase. Clepper said some aircraft structure and various equipment are heavier than expected.

The increased weight has become apparent only as Douglas has begun turning out the 15,400 engineering drawings that will be used to build C-17 components.

Clepper said 10,000 of those drawings have been released to manufacturing operations, so weight projections are becoming more accurate.

After the first C-17 is completed, Douglas will roll it onto a scale and measure the weight for the first time. Generally, the aircraft industry is able to estimate weight within 1% to 2% of the actual amount, once the engineering drawings are completed, Clepper said.

Even with the weight growth, there was enough “margin” in the performance estimates that contractual requirements will still be met, except for the ferry range. As for that requirement, he said Douglas is currently negotiating with the Air Force for “specification relief.”

In exchange for a reduction in the performance, Douglas is offering the Air Force some additional features, such as a satellite communications capability for the aircraft, he said. That is being done at Douglas’ cost, Clepper added.

Douglas is developing the aircraft, which includes building one flying prototype and two ground test aircraft, under a firm fixed-price incentive contract that has a “target” price of $4.24 billion. If Douglas exceeds the target, the government pays 80% of the cost up to a ceiling of $4.91 billion and then Douglas bears the full overrun.

The most recent cost estimate to complete the contract showed that Douglas was “a couple of percent above target,” Clepper said.

“We are running pretty close to target,” he said.

Air Force officials have continued to express confidence in the program. In January, the service exercised an option for the first two production aircraft and provided funds for long lead items for the next four aircraft.