Monday, September 3, 2012

Edwards AFB reports more progress in F-35 testing

While Eglin AFB celebrates their 200th sortie focused on training pilots for the F-35, Edwards AFB's F-35 test pilots have pushed past their 350th sortie as they continue to test the aircraft's limits.

They've completed the air restart testing. That has allowed them to move into other areas according to Lt.Col George Schwartz director of the F-35 integrated test force and commander of the 461st Flight Test Squadron.
"That allowed us to go into high AOA testing where we will start expanding the envelope from 20° AOA all the way up to 50° AOA," Schwartz says. "It's going to start probably in September."
Much of the activity has focused on high speed tests which have seen the F-35 being repeatedly pushed out to its maximum speed of Mach 1.6 and 700 knots calibrated airspeed-often fully laden with internal weapons.
Another ongoing theme for the Edwards test pilots is maturity testing for the software required for the F-35 training mission currently underway at Eglin AFB, Florida.
The AOA testing will begin soon:
Initially, test pilots will simply push the F-35 out to 50° AOA. But then the veteran aviators will have to intentionally depart the aircraft from controlled flight in order to gauge how the jet behaves under those conditions. They will also evaluate the F-35's departure recovery procedures and its departure resistance characteristics. "It's the kind of stuff a test pilot dreams of doing," Schwartz says.

Like the transonic region of the flight envelope, high AOA testing flight is particularly tricky. While there have been improvements made, there are still some transonic roll-off problems--where the aircraft begins an uncommanded roll at speeds between Mach 0.9 and Mach 1.2--that have yet to be fully ironed out on the F-35. Those problems are being fixed with tweaks to the F-35's flight control laws. But Schwartz says, similar discoveries are possible in other challenging parts of the envelope like high AOA flight. "We expect to find stuff and we'll get it corrected," Schwartz says. "That's why we're here."
As those faults are discovered in testing, they'll be tweaked and applied to all current and future F-35s.

The beauty of concurrency, though, is while this testing is taking place, Eglin AFB has already flown 200 sorties training pilots and maintainers. That means fielding both the aircraft and the personnel necessary to fly and maintain them at an earlier date than had linear development been used.

As mentioned earlier, there's extensive testing of the software going on concurrently as well:
In addition to physical tests of the airframe and weapons, there are also extensive mission systems trials ongoing at Edwards. The integrated test force has already finished vetting the F-35's Block 1B software, which begins to fuse some of the data from the jet's myriad sensors, Schwartz says. That software is now being deployed with the training fleet at Eglin AFB. So far, the software has become more and more stable as testers wring out the problems and the code is corrected in later releases. But there have been some "minor integration issues," Schwartz says.

Currently, Edwards is testing the "very last part" of software Block 2A. Schwartz says that testing is complete for the low rate initial production Lot 4 jets' software. The test force is hoping to be flying with the Block 2B software load starting in the fall. "That's the one that going to be going into the first big operational test period," Schwartz says. It is also the software block that the US Marine Corps hopes to declare initial operational capability with on the F-35B.
And, very soon more weapons testing:
There are also ongoing trials with external weapons loads and pilots at Edwards hope to start testing weapons separations soon. Currently, all weapons pit drop tests required for the system development and demonstration (SDD) phase, save for the 250lbs GBU-39 small diameter bombs, have been completed. "We're just getting ready to do our first weapons separation and that'll be in the October timeframe," Schwartz says. "We're going to do a GBU-31 and an AIM-120."All in all very encouraging reports coming out of both Eglin and Edwards AFBs on the progress of the F-35.
All in all some very encouraging news on the testing and vetting of the F-35. Progress on all fronts and still well ahead of schedule.


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