First Flight of Air Force Tanker Test Plane Delayed a Month
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KC-46A "Pegasus"
Seattle Times | Aug 18, 2015 | by Dominic Gates
The first flight of Boeing's KC-46 Air Force tanker test plane will be delayed by "roughly a month" because some parts of the fuel system were corroded when the wrong fluid was poured in during a ground test last month, the company said Monday.
Boeing spokesman Chick Ramey said the first flight of a fully equipped tanker, which had been expected in late August or early September, is now pushed about a month beyond that.
However, Ramey said that despite this latest setback, Boeing continues to build production tankers and to fly tests of another jet that has the same 767 airframe though it doesn't have a working tanker fuel system.
As a result, he said, Boeing doesn't expect this tanker flight-test delay to affect the ultimate end target: delivery of the first 18 operational KC-46 tankers to the Air Force by August 2017.
Late last month, when the first test plane outfitted with working air-refueling systems was at the fuel dock on Paine Field, mechanics used a chemical during a test of the fuel system that had been mislabeled by the supplier.
"It was a fuel substitute to simulate the weight of the fuel during a test," said Ramey. "It had been labeled compliant for that military use, and it wasn't."
The chemical damaged the tanker's complex fuel system, which provides gas both for the jet's own engines and for dispensing to other aircraft through the jet's air-to-air refueling mechanisms.
According to people familiar with the details, the large, extra fuel tanks in the aircraft fuselage were not damaged, but the chemical corroded tubes and couplers that connect the various parts of the fuel system.
"We flushed the affected parts, and some of those parts have to be refurbished or replaced," said Ramey. "We're doing that now."
The flight-test schedule is already very compressed due to earlier delays.
A key program milestone previously scheduled for this month was already pushed out to next spring, as late as April. It's the Pentagon's formal go-ahead for Boeing to build production tankers, which comes only after the company has successfully demonstrated the required refueling capabilities during flight tests.
Now Boeing will have one less month to get the flight-test results it needs for that formal approval.
In the meantime, because it cannot meet the end delivery target any other way, Boeing has begun building the first production tankers even before the first KC-46 test flight, much less the formal Air Force go-ahead.
That, of course, introduces risk.
If flight tests turn up issues that require design adjustments, any already built tankers will have to be retrofitted, which is much slower and more costly than doing modifications during the initial assembly process.
In July, before the latest setback, Boeing announced an $835 million write-off due to higher costs associated with fixing an earlier problem in the tanker's fuel system.
When engineers ran pressure tests on the fuel system of the first plane, some of the internal connectors blew out, rupturing the system, which had to be repaired and redesigned.
Air Force spokesman Ed Gulick said then that the delays from that issue meant "all previous schedule margin is gone."
The July write-off, Boeing's second accounting charge to the tanker program, brought the total cost overrun during development to $1.3 billion.
The Air Force requirement is for delivery of 179 planes by 2027, valued at about $50 billion.
Boeing forecasts a total global market for refueling aircraft of $80 billion.
http://www.military.com/daily-news/2015/08/18/first-flight-of-air-force-tanker-test-plane-delayed-a-month.html
