62 AVIATION WEEK & SPACE TECHNOLOGY/MARCH 30-APRIL 12, 2015 AviationWeek.com/awst
geared specifi cally to address multi-
ship fusion shortcomings. It was de-
cided among the test team and JPO to
move forward with it in parallel with
work to certify the 2B software with
which the U.S. Marine Corps plans to
declare F-35B initial operational ca-
pability (IOC) in July.
“We think before we release this to
the Marines, there need to be some
improvements,” says Air Force Col.
Roderick Cregier, the F-35 program
director at Edwards.
The Marine Corp s has said it will
proceed with the IOC this summer with
or without these ETB improvements.
But JPO of cials hope to have them on
those early jets before the milestone,
spokesman Joe Dellavedova says.
The ETB altered about 900 lines of
code specifi cally to ensure that each
pilot in a multiship formation sees the
exact same threat picture as his wing-
men, the testers say.
Originally, the program called for
fielding the jet with its more-robust
3F software. With 3F, pilots can use
external weapons stores, the infra-
red search-and-track function of the
Electro-Optical Targeting System
and a wider variety of weapons. How-
ever, obstacles earlier in development
prompted the Pentagon to prioritize
the B version, which w as optimized for
Marine Corps’ short takeof and verti-
cal landing—and allow for IOC with this
baseline software.
“Block 2 was never intended to be
fi elded software. So the fact that we
can get to a point where we have these
discussions of how usable this aircraft
is in an operational environment right
now is a success,” says Lt. Col. Andrew
Allen, director of the integrated F-35
test force at Edwards. “If the Marines
are going to use it right now... in our
expert opinion [we need to know] what
needs to be addressed.... We want to
do better than this. We think we can.
We still have time to do it, so let’s go
do extra stuf .”
The team created the software
patch in 22 days from when the deci-
sion was made to proceed, which was
in February. Test sorties are planned
through the end of March.
The patch was loaded onto two test
aircraft, which fl ew with it for the fi rst
time on March 12. The teams also plan
to load the patch onto a third and pos-
sibly a fourth F-35. The requirement to
determine mission ef ectiveness is for
three aircraft to have the modifi cation,
but a fourth could add more data to the
fi nal determination, Allen says.
“Fusion development is an extremely
iterative process. It almost crippled
the F-22 program. Now you are taking
multiple, federated sensors and trying
to integrate them,” he says. Allen also
participated in the F-22 program. He
notes that the F-35 program is “light
years ahead” of where the F-22 was in
this stage, which is when the twin-en-
gine stealthy jet was experiencing em-
barrassing avionics shutdowns during
fl ight. This prompted pilots to have to
reboot systems multiple times during
a sortie.
“What we have done in the program
up to this point has been full software
releases. There have been no quick
[patches].... What we are getting for
the fi rst time ever is a little bit more
agile. It is a patch [and] if it is good,
we will roll it into the next software
release,” Cregier says.
As they continue testing, engineers
are assessing just how much of which
type of data should be transmitted
among the aircraft to create the threat
picture. “Inviting other aircraft into
your fusion system... that is an ex-
tremely dif cult thing [and] you have
to find that sweet spot of how much
data do you let in” to the network, Al-
len explains.
If needed, the schedule could allow
for an additional ETB patch or two, he
adds.Meanwhile, the team is also conduct-
ing early testing on Block 3F software.
Thus far, they have begun conducting
asymmetric load tests on AF-1. Exter-
nal weapons carriage is a feature added
with Block 3F, with which the Navy will
conduct IOC by February 2019; it is un-
available for Blocks 2B and 3i for the
Marine Corps and Air Force IOCs.
The conversion to 3F from 3i takes
about a week, according to David
Nelson, a Lockheed Martin test pilot.
Thus the test fl eet is working with
the 2B, 3i and 3F software packages at
varying levels. This is possible, in part,
because of the infusion of fi ve mission
systems aircraft—some pulled or on
loan from other locations and mis-
sions. These were added when the pro-
gram was restructured in 2011 to miti-
gate risk in the software work delaying
fi elding. Originally, the team planned
for a single mission systems jet.
Earlier in the program, of cials as-
sumed the bulk of mission system test-
ing would take place in ground-based
laboratories or in the Combined Avion-
ics Testbed, a fl ying Boeing 737 modi-
fied with an F-35 radar, sensors and
leading edges, Cregier says.
Thus far, the F-35 is about 60%
through development, which is slated
to fi nish in 2017. cDEFENSEA new light for the F-35’s refueling
system—redesigned to reduce
glare for KC-135 boom operators—
is installed on the red extender
arm bracing the refueling probe
of this test aircraft.F-35 AF-1 conducts
asymmetric load
testing, including
the use of external
weapons stores,
during recent
fl ights using
newly installed
3F software.LOCKHEED MARTIN/TOM REYNOLDS PHOTOSDigital-Extra Meet the F-35 fl ight-test
fl eet at Edwards AFB:
AviationWeek.com/F35Edwards