Lockheed Martin and US government officials leading the F-35 Joint Strike Fighter have disclosed tantalising new details of the metrics required to complete the programme's nearly seven-year flight-test schedule on time.
Since the AA-1 prototype achieve first flight in December 2006, the programme has completed 100 flight test sorties by three aircraft over a two-and-a-half-year period.
That schedule will ramp up dramatically as 10 new prototypes are added to the flight-test fleet through 2010, even as the non-weight-optimised AA-1 is retired from flying status.]
© Lockheed Martin
Through the end of 2010, the sortie rate will be limited as the programme qualifies a full cadre of pilots and maintainers to complete the 5,000-sortie flight-test programme by September 2013, says Dan Crowley, Lockheed's executive vice-president for the F-35 programme.
The sortie rate gains full steam starting in the 2011 timeframe, when the 12-aircraft test fleet is expected to start averaging a maximum rate of 144 flight hours a month, Crowley says.
At that rate, the programme could generate a maximum of about 1,600h a year.
That monthly rate assumes that each of the 12 aircraft in the test fleet will generate 12 sorties a month, says Brig Gen David Heinz, Lockheed's programme executive officer.
Even if two or three aircraft fail to generate those rates, says Heinz, the programme still has enough time and resources in the flight-test programme to remain on schedule.
In fact, the 5,000-sortie rate programme anticipates that up to 15% of the flight sciences test points and up to 25% of the mission systems test points will be devoted to overcoming errors found in the design or in the tests, Heinz says.
The 12-sortie monthly rate has already been demonstrated by the AA-1 prototype in the April timeframe, Crowley says.
Previously, Heinz has explained that the projected F-35 sortie rate is less than the actual amount achieved about a decade ago during flight tests for the Boeing F/A-18E/F Super Hornet. Heinz said that number was 13.2 sorties a month.