Amid a Year of Challenges, F-35C Sea Trials Progressing Well
ABOARD THE USS NIMITZ — For those involved with procuring, developing, testing and piloting the naval variant of the joint strike fighter, the past week of F-35C sea trials has been a reprieve from technical challenges, including engine problems and issues with the tail hook that led to a complete redesign.
The flight tests kicked off last week when the CF-03 test airplane successfully landed Nov. 3 on the deck of the USS Nimitz aircraft carrier. Since then, the aircraft has completed more than 26 flights,
including more than 100 catapult launches, 214 touch-and-go landings and 102 arrested landings as of Nov. 12, according to Navy statistics.
The F-35 performed its first night flight on Nov. 13, joint program office spokesman Joe DellaVedova said in an emailed statement.
“We expected to come out here and have to figure some issues out, and surprisingly everything has been going well,” Cmdr. Tony Wilson, a test pilot at Patuxent River, told reporters. The aircraft has integrated onto the carrier without any major problems.
"We're learning things, but everything that we're learning is extremely minor," he said. He declined to comment on any performance or design issues.
The Navy has completed about 95 percent of the test items it set out to perform during its two weeks at sea, as well as additional “nice-to-have” points that can inform later trials, Cmdr. Sean Kern, director of test and evaluation for Patuxent River’s integrated F-35 test force, said Nov. 13.
Still on the to-do list are catapult launches in crosswind conditions and recoveries in 40-knot or higher winds. Pilots have flown flights in those high winds during the past week, but more data is needed, he said.
The Navy is the last of the services to field the joint strike fighter, with initial operational capability in fiscal year 2018. Its variant is also the most expensive, costing about $130 million per unit in low rate initial production lot 7.
During a media day aboard the Nimitz on Nov. 13, CF-05 test aircraft took off, flew in pattern around the carrier, and performed an arrested landing. Its tail hook caught the third wire on the ship, which the Navy considers optimal for safety.
Those third-wire engagements have been the norm during tests, Wilson said. So far there has been only one bolter — when a pilot touches down too late and fails to catch onto a wire. The pilot executed a planned touch-and-go, but touched down after the fourth and final wire, technically qualifying it as a bolter.
Navy officials could not comment on whether that was the result of pilot error or an issue with the F-35’s new “delta flight path” technology, which helps automate landing on the carrier.
Wilson said delta flight path had performed well in testing and would help to unburden pilots during normal operations, likening it to having cruise control in a car.
"This flight control scheme is revolutionary and is going to pay huge dividends for the Navy,” he said. “It's going to make landing on the boat a routine task, and right now landing on the boat is anything but a routine task. That's why the Navy invests so much money into training its pilots and continually training them.”
Another positive finding was the performance of the F-35C’s new tail hook. During the original hook’s initial tests at Naval Air Engineering Station Lakehurst in New Jersey, service officials found the hook did not engage with the cable, said Thomas Briggs, head of the air vehicle engineering department at Patuxent River.
Lockheed Martin then redesigned the tail hook with the input of Atlantic Test Range personnel, he said.
It passed structural demonstrations earlier this year at Patuxent River, but critics like Michael Gilmore, the Pentagon’s director of test and evaluation, cautioned that the increased weight and sharpness of the new equipment could cause damage to the flight deck.
However, the gear has been catching the wires on the carrier deck without gouging or otherwise damaging the surface, Wilson said.
The F-35 is planned to return to the carrier for sea trials in summer 2015, when testers will gather data about how it performs with munitions inside its internal bomb bays, Briggs said. In the third set of trials, external payloads on its wings will be added.
Because most of the mission systems testing apply to all variants, they can be tested ashore, Kern said. Once they mature through testing at Patuxent River and Edwards Air Force Base, “we’ll bring that capability out to the ship and then look at specific issues involving ship integration out here.”
“What we have been looking at here is some of the electromagnetic effects to see if there is any interference issues between the ship’s equipment and the aircraft’s equipment,” he said. “We haven’t found any” during this round of sea trials, he added.