Understanding F-35 flight test "progress"

Thanks to a reader for taking the time to post this comment from First drop of a test weapon shape from F-35.

It deserved its own thread:

Anonymous said...

Pro-JSF forces will claim progress, but fail to understand what is before their eyes. Anti-JSF forces will look at elapsed time since program win and bring the guns to bear on the slow pace of achievement.

BF-3 is a dedicated "flight sciences" jet just like BF-1/2/4, with no capability for "mission systems" testing - which only resides in BF-5, and they have yet to get that jet's systems working correctly since delivery from Ft Worth.

This test was conducted to merely check the actual vs predicted separation clearance of the GBU-32 from the bay at a conservative speed/altitude. This is a normal flight test stepping stone which will require a decent amount of postflight analysis (1 week nominally, but pressure is surely "on" to do better) prior to proceeding to the next test point.

As with every integration of JDAM on any platform, the first tests involve the "flight sciences" aspects and often occur in parallel: flutter, loads, environmental, and separation testing. These do not require any smart integration with the weapon. Much has gone on in the background to get to this point. Yet what has not gone on with the BF's has been any integration of the GBU-32 into the avionics system, other than declaring a quantity and weapon weight.

The drop seen here was not in any way an "integrated test". The weapon bay has multiple cameras, as does the aft end of the fake EOTS housing under the radome...and the AIM-9X shape possesses two cameras. All of these fixed apertures are cued during release, with the digital images stored in the test instrumentation system of the jet. These are used postflight to determine miss distances, by using the accurately placed black/white targets on the jet and weapon as references. These are digitally combined in a computer program and an accurate X/Y/Z accounting of the weapon is generated (in relation to the jet), thus the miss distance can be calculated. If it falls within a given percentage of the preflight prediction, engineers will give the test a pass and the release envelope is opened a little further.

The weapon seen here was not guided, nor did it communicate with the jet in any way. It was merely a "shape" that was measured/ballasted/weighed/targeted so that it mimicked a real GBU-32. The weapon bay doors were driven open via pilot command minutes before release, not via some automated all-up round command (commit to weapon release) that will be required of a mission systems jet (and operational jets, obviously). The weapon was literally released via a manual command from the pilot, with the pickle button actually hot-wired to the release mechanism in the bay. Very simple, and all that is required for a separation test.

Do not get the idea that a JDAM was powered up, GPS keys and almanac downloaded, passed a mass data transfer, aligned, and given target coordinates. Sadly, the program is not to that state even yet. Weapons have been removed from IOC for the variants so they can just get the GBU-32 or -31, GBU-12 PWII, and AIM-120. Even those will be very limited as the program will not be able to clear them to complete envelopes. Very sad as lots of competent people at LM and DoD have proven themselves on previous programs, yet get absolutely overrun when trying to change the immense inertia of a program run by very few with ANY aerospace background. This is not isolated to LM...Boeing and NG have their share of PowerPoint managers in positions of program power. DoD test leaders are lacking in experience but not in speedbump-like opinions. And test pilot careers are more important at this point than louldly waving the warning flag at impending OT failures. Progress to flight hours and test points (regardless of success) runs the show.

Of course the LM business development machine and the Navy's Army's Air Force (USMC) will spin this simple separation flight into a "we have dropped JDAM from the F-35 and support the warfighter" story that lawmakers and laymen will soak up.

UK to have degraded air-defense capability with the F-35

Since the start of the UK signing on to the F-35 Joint Strike Fighter (JSF) program years ago, it was briefed that one of the weapons to be cleared for internal carry by the end of systems development and demonstration (SDD) phase with UK jets was the ASRAAM AIM-132 air-to-air missile.

Now, according to a briefing by program officials earlier this year, it seems that the AIM-132 will only be cleared for outside carry--the non-stealth mode--by the end of SDD.

There have been other degraded affects with the AIM-132 and UK F-35. Back in 2008, program officials announced that it was just too much work to clear the AIM-132 for carry on internal air-to-ground hard-points. In each of the F-35's two internal weapon's bays you have one hard-point which can hold either an air-to-ground weapon or an air-to-air weapon. One door from each of the two bays can also hold an air-to-air missile. This gives the potential for the F-35 to carry 4 air-to-air missiles internally.

Originally the UK expected to have the ability to carry 4 AIM-132s internally; 2 for each weapons bay. With the 2008 announcement, that left the UK with 2 internal carry AIM-132s (hung on the internal part of one of the weapons bay doors) and the other two would be carried externally. In 2008 it was passed off that the external carry would be with low-observable hard-points to carry the missile but program officials have already stated that if you carry weapons externally, you are not stealthy.

A March 2012 briefing now shows no internal carry of the AIM-132 for the end of SDD.



Compare that to this 2009 slide (from a Lockheed Martin 2010 briefing) which reflects what has been briefed for years in relation weapons cleared by the end of SDD. Those weapons with pink text labels.

Ignore the pink on the external fuel tanks. That went away in 2006 when trying to figure out stores separation became too troublesome. Note that the 2012 brief still assumes the UK will have the F-35C. This is no longer so. They are back to the F-35B.

The 2012 brief also has some interesting items about schedule best left for another post.

It will be interesting to see how program officials respond to the idea that the UK just recently said good-bye to internal carry of the AIM-132. An industry observer and military aerospace engineer not attached to the program put forth some possibilities:

ASRAAM is a rail launched weapon so the body is likely not designed to take the loads of an ejection and the exhaust would burn the beejeesus out of the weapon bay, with exhaust plume byproducts being blasted into the bay and onto everything in its flight path, like the EOTS sapphire window.

Then there is the under fuselage crossing angle issue with a rail launch from the door station which would somewhat seriously hinder simultaneous or closely spaced dual launches to consider.

Most likely too, it was yet another case of the PowerPoint not matching engineering reality. Quite normal for this program. Woe to the U.K.

So what does that leave the UK with? AMRAAM. However that has its own trouble with production reliability considering the 2-year-old motor problem and overly optimistic probability-of-kill claims against high-end targets.

The U.K. is currently running a going-out-of-business sale with the military. How the F-35 will help any improvement in their combat capability is a large question.

It may be possible to see weapons clearance options catch up after SDD. However the way the program is struggling, that is the least of the worries for the F-35 faithful who are trying to keep the cause alive.