Lockheed Martin and the US Air Force are working on implementing an automatic ground collision avoidance system (auto-GCAS) for the service's F-16 Fighting Falcon fleet that is set to become operational in 2014.

The system will also include a pilot activated recovery system that would be able to return the jet to straight and level flight at the push of a button, should the operator become disoriented.

"We expect to have the production deliveries out in the field as part of the M6.2+ OFP [Operational Flight Programme] for the USAF," says Bill Hord, a Lockheed F-16 programme director. "It fields in early 2014."

The F-16 auto-GCAS has three main components including advanced data transfer equipment, which houses the necessary algorithms and data, a modification to the digital flight control computer and modified software for the jet's modular mission computer. "Those three components are coming together and we are ready to go," Hord says.

The digital flight control computer passed its airworthiness certification one-and-a-half weeks ago, Hord says. "Those modifications have been reviewed and approved by the air force," he adds.

The operational flight programme for the modular mission computer will still have to be certificated and subsequently, the entire system will have to be flight certificated. The whole system is expected to be certificated before the end of 2013 with installations starting in the second quarter of 2014, Hord says.

Those modifications will be retrofitted to the F-16 fleet as the aircraft undergoes depot maintenance at Hill Air Force Base (AFB), Utah. The USAF currently has the capacity to modify 25 aircraft per month, but hopes to ramp up this rate to 50 per month. If all goes well, the entire active USAF F-16 Block 40/42/50/52 fleet will be retrofitted before the end of 2014.

Older F-16s, which have analogue flight computers, will not receive the retrofit. However, the Air Force Research Laboratory (AFRL) does have a technical solution in hand should the USAF's Air National Guard or Reserve choose to add the system to their jets.

The auto-GCAS has been a long-term effort for the USAF. General Dynamics (the original F-16 manufacturer before the division was acquired by Lockheed) and the USAF have been working on auto-GCAS technology since the mid-1980s, starting with Advanced Fighter Technology Integration (AFTI) F-16.

In those days, there was simply not enough data storage capacity available on board an aircraft to operationally implement a digital terrain elevation data (DTED)-based auto-GCAS system. Advances in computer hardware make the current system feasible.

"The only problem there [with the AFTI F-16] was having sufficient data storage capacity that was rapidly accessible to get the necessary terrain data out of it, and so it wasn't really a good implementation," Hord says. "Now that we have all the bits and pieces together, the technology is ripe. We're going as fast and hard for it as we can."

Development of the current system began in earnest under the AFRL's Fighter Risk Reduction Programme in 2007, Hord says. That risk reduction effort, which included a number of demonstration flights, ran through the middle part of 2010. Having developed the auto-GCAS as a specific functional capability for the purposes of the demonstration, Lockheed was then tasked to develop the production version of the system, Hord says.

Flight testing of the production auto-GCAS system started in the early part of 2011 and is currently ongoing at Edwards AFB, California. "The risk-reduction programme - the auto-GCAS specific programme - never really stopped," Hord says. "It's contributing some of the changes. There's a few additional tweaks to go in."

One such tweak is that while the system is technically capable of recovering the F-16 at 15m (50ft) above ground level, feedback from test pilots suggested the recovery altitude to be set at 152m.

While the F-16 will be the first USAF aircraft to receive an auto-GCAS system that uses DTED maps, a less sophisticated auto-GCAS system is being developed for the Lockheed F-22 Raptor. The F-22 auto-GCAS, which is currently being flight tested at Edwards AFB, requires the pilot to manually set a floor altitude and does not use digital terrain data. In addition to the Raptor, Lockheed's F-35 and the Boeing F/A-18 will also receive DTED-based auto-GCAS systems similar to the F-16's.

However, the Pentagon is not the first to implement such an auto-GCAS system for its tactical fighter fleet; some advanced foreign F-16s already have technically superior systems installed.

Source: Flight International