WASHINGTON — With just one test to go, the F-35 joint program office is confident that modifications made to the aircraft's helmet and ejection seat will ultimately fix issues that greatly increase the risk of casualties to lightweight pilots upon being ejected from the plane.

For Martin-Baker, which makes the US16E seat inside of the F-35, that test data could mean the difference between the Air Force deciding whether or not to qualify a competing company's seat — United Technologies' ACES 5 — in what could be the first step to replacing its own product.

Last year, the Air Force acknowledged that F-35 pilots below 136 pounds were at a higher risk of severe and potentially fatal neck injury, leading it to restrict all pilots below that weight from flying the jet. The service took a step further this summer when Lt. Gen. Arnold Bunch, its top uniformed acquisition official, requested that the JPO study the cost and schedule implications of qualifying the ACES 5 model as a potential replacement.

In an exclusive interview with Defense News, JPO officials said they expect the Air Force will be able to remove all weight restrictions following the final test of the modified escape system later this month. Preliminary data indicates that the upgraded seat and lighter helmet will have removed what the service termed "excessive" and "elevated" risk to light and mid-weight pilots, said Todd Mellon, the joint program office's executive director.

"We're three to four weeks away from having all of the data done so that we can finalize the technical assessment, put that into a risk assessment, and then ultimately make a recommendation," Mellon said Sept. 16. "We expect all of that to come together towards middle or late October. All indications based on the data we've evaluated and the preliminary results through yesterday are favorable."

The JPO is overseeing three adjustments to the aircraft's escape system. Martin-Baker is installing a switch in the seat, which triggers software modifications that change the parachute loads to meet the needs of heavier or lighter pilots. The company also introduced a head support panel that helps alleviate head and neck issues. Meanwhile, Rockwell Collins has been working on driving down the weight of its helmet from 5.1 to 4.6 pounds.

By the end of the month, Martin-Baker and the program office will have conducted 21 sled tests, which gauge the impact of being ejected at different speeds and altitudes. Some testing occurred at Martin-Baker facilities, while other data was collected during service-led events at Holloman Air Force Base, New Mexico.

Eight of those demonstrations employed a 103-pound mannequin, which was used to verify the escape system’s ability to eject the lightest-weight pilots able to operate the plane, said Navy Lt. Cdr. Nick Sinnokrak, the JPO's crew systems lead. At completion, six of the 21 tests will have also included the lightweight helmet. Five demonstrations included all three factors associated with proving the fix: the upgraded ejection seat, a lightweight helmet and a 103-pound dummy.

The final demonstration at the end of the month will use a heavyweight mannequin to test both the upgraded seat and helmet at 550 knot speeds, said Andrew Martin, Martin-Baker's director of business development and marketing.

It’s unclear whether the blame for the issues stems from the helmet, the ejection seat or some combination of the two factors, and JPO officials refused to point fingers at any one product. However, Martin-Baker has borne most of the scrutiny and stands to lose the most if the upgrades do not prove successful.

Martin acknowledged that there would certainly be a financial impact to Martin-Baker if the Air Force decides to purchase a different seat. With a 1,763-jet program of record, the service is by far the biggest F-35 customer. However, Martin said he believes the potential impacts to the joint strike fighter’s cost and schedule would ultimately deter it from the United Technologies system.

"No one will high-five the world more than myself when the final test is complete, which I'm sure will be a success, and the world and the program can move on to focusing on other things," he said. "But I really don't take the scenario of the Air Force changing the escape system seriously at all. For that to happen, we would be talking about $50 million and a test program that would take three or four years, at best, for an alternative."

A Challenger Appears

The Air Force has not yet been briefed on the potential cost or schedule implications of qualifying the ACES 5 system, which the JPO expects to discuss later this year. For now, the service is remaining mum on whether it will seek to qualify the UT seat even if the Martin-Baker fix meets requirements.

"It’s too early to say because we don’t know what that information is going to say," an Air Force official said on background.

The JPO, however, has been reluctant to qualify a second seat. Buying the US16E for all services and international customers allows the office to benefit from economic order quantity. If the Air Force opts for the ACES 5, that seat could be more expensive — and could lead to an increased US16E price for other buyers.

It could also create problems with the F-35 program's international participation if Martin-Baker, which is based in the UK, is forced to take on a smaller share of work.

The qualification process will likely take "a couple years," so the JPO will move forward with the retrofit plan as a stopgap even if the Air Force decides to qualify the United Technologies model, Mellon said.

The timeline "really has a lot to do with how many shots do they need to do, what other work do they need to do in terms of engineering related to the seat," he said. "Again, we would have thought we would have a qualified seat a couple years ago from Martin-Baker, and we saw what happened."

The JPO team is currently analyzing what data points it will need to independently gather to qualify the ACES 5, said Air Force Lt. Col. Scott Bjorge, F-35 JPO Air Vehicle Lead. "We’re going to look at the cost to conduct those tests, whatever it may be, and the schedule associated with that as well."

He stressed that the study will only estimate the impacts of qualifying the UT system, not of procuring, integrating and sustaining the seat. The Air Force would need to request yet another study to obtain that information, which could occur concurrently with the qualification tests of the ACES 5 seat— should the Air Force decide to move forward on that option.

"At that point, if the Air Force would like us to do that, they’ll have a qualified seat that they could do nothing with, or they could decide to ask the JPO to put it in the next production jets, or they could ask us to retrofit all of the Air Force jets," Bjorge said.

Upgrading Existing Aircraft

The joint program office laid out a preliminary plan to retrofit the Martin-Baker seats last week during a visit to Lockheed Martin’s Fort Worth, Texas-based facilities, and will be prepared to proceed once the Air Force concurs with the JPO’s recommendation to remove flight restrictions, Mellon said.

"We expect that to happen in October," he said. "We will have everything ready to begin the retrofit program in October, but we will not begin retrofit without concurrence."

It will take about two years to complete the entire retrofit process, said Bjorge. "On the seat side, we’re going to target the training bases, because there are currently no lightweight pilots in the airplanes, so the only way to enter the pipeline is through the training pipeline."

Martin-Baker and the JPO have already done some advance work to allow retrofits to begin quickly after the seat is re-qualified, Bjorge said. The parts needed for the upgrades are scheduled to arrive in November for immediate installation into seats.

Teams of Martin-Baker engineers will be responsible for modifying the seats at the Air Force bases, said Martin, who estimates that each seat will take about four days to complete.

In the beginning stage, the team will complete about 14 seats per month, ramping up to around 28 seats in 2017, Sinnokrak said.

The lightweight helmets will also begin coming off of Rockwell Collins’ production line this November,  but will be limited to six units this year, said Rich Lukasik, the JPO’s helmet mounted display lead integration engineer. Pilots below the 136-pound weight threshold will be the first to obtain the helmets. Full production of the lightweight helmet starts in 2017.

"Once we begin and get the ramp to an appropriate point, the only thing we’ll produce is the lightweight helmets," Mellon said.