F-35 Joint Strike Fighter program proceeds apace

 - June 27, 2007, 6:58 AM

All systems go! That was the message from the Lockheed Martin F-35 Joint Strike Fighter briefing at the Paris Air Show last week. The first test flights have already provided good validation of some of the aircraft’s unique features. The eight international partners are all still onboard, all having signed up for the production sustainment and flight development (PSFD) phase over last winter.

There are now 12 development aircraft in fabrication, said Brigadier General C.R. Davis, U. S. Air Force, who is the F-35 program executive officer. A Boeing 737 converted to act as a co-operative avionics test bed (CATB) has completed airworthiness flights, and should soon start proper test flights. The Pratt & Whitney F135 powerplant has amassed more than 7,000 flight test hours.

Because of some late changes to the F-35’s internal structure, to reduce weight, the first development aircraft AA-1 is not fully representative. Nevertheless, Davis said, much has been learned from the early flight tests, and AA-1 has proved autopilot functions plus flight control hardware and software – including back-up systems, that operated during an actuator failure on the 19th flight. Davis also noted that the F-35’s integrated power package is performing well. “It had been considered a high-risk element,” he added.

The pilot’s helmet mounted display (HMD), although not ready for the first few test flights, is now flying on the aircraft. The HMD assumes great importance on the F-35, since there is no head-up display.

Davis noted that there are as many as 19 million lines of software code in the program, including ground-based training systems. Six million of these are for the aircraft itself. Of all this, 41 percent has been written to date, only 1 percent below target.

The second aircraft to fly will be a short take-off and vertical landing (STOVL) F-35B version. This is now in final assembly at Lockheed Martin’s Fort Worth factory. There are four more STOVLs, four more conventional take-off and landing (CTOL) F-35As, and two carrier-based (CV) F-35C aircraft in the flow. The critical design review (CDR) for the CV version is being held this week at Fort Worth, said Davis.

There has been some controversy over the concurrency of the F-35 development program with the low-rate initial production (LRIP). The plan calls for the first two production aircraft (LRIP Lot 1) to be delivered to Eglin AFB for training in early 2010. Davis agreed that it was a fast-paced schedule. But “if we slow it all down, it becomes more expensive for all nine partners,” he added. 

Tom Burbage, executive v-p and general manager of the F-35 program for Lockheed Martin, sought to reassure the audience. “The digital thread, the use of the CATB, and other risk reduction efforts, simply weren’t in previous programs.”

And so the world’s biggest–and possibly its last–fighter show rolls on. The Eurofighter and Saab Gripen teams are doing their best to dislodge Denmark and Norway from the F-35 program. But they failed to do so at the PSFD stage. The international partners do not have to make a production commitment for another two years. But Davis is already looking forward to signing up the next level down participants in this program, who have paid to get detailed, classified information. These are Israel and Singapore.