Clear Deck

The two F-35Cs are specially configured integrated test force (ITF) jets operated by the US Navy’s VX-23 Air Test and Evaluation Squadron based at NAS Patuxent River in Maryland.

This first series of trials is dubbed Developmental Testing I (DT‑I) and was planned to last two weeks.

“Today is a landmark event in the development of the F-35C,” the aircraft’s pilot, Cmdr Tony ‘Brick’Wilson, said after the landing. “It is the culmination of many years of hard work by a talented team of thousands. I’m very excited to see America’s newest aircraft on the flightdeck of her oldest aircraft carrier, the USS Nimitz. ” During DT-1 the test team has been performing fit and maintenance checks of the jets and their support equipment in the carrier’s hangar, lifts and on deck, and is conducting a series of catapult launches and arrested landings across an initially conservative flight envelope. Both aircraft have been instrumented for the trials, and the results will be closely scrutinised to better inform future trials and eventually, F-35C carrier operations.

Vice Adm David H Buss, Commander of Naval Air Forces, was aboard the Nimitz to witness thelanding. “What a historic day today is for naval aviation,” he said.

“With the first traps and catapult launches of the F-35C Lightning II aboard an aircraft carrier, we begin the integration of the next generation of warfighting capability into our carrier-based air wings. This important milestone is yet another indicator of naval aviation’s ongoing evolution to meet future threats and remain central to our future Navy and national defense strategy. ” The sea trials had been delayed about a month following June’s F-35A engine fire at Eglin AFB which resulted in the likely total loss of the aircraft, and the fleet initially being grounded before flight restrictions were imposed. The fire in the F135 engine was attributed to a rubbing of low pressure compressor blades against an abradable strip during an aborted takeoff roll, and resulted in aircraft AF-27 being extensively damaged. Engine maker Pratt & Whitney recently agreed to a number of changes to production engines to alleviate the possibility of this recurring, as well as a retrofit fix for engines already in service. While some flight envelope restrictions remain in place for operational and training squadrons, the test fleet jets have been cleared to their full envelope.

The sea trials follow an extended period of land-based arrested landings and catapult launches at NAS Patuxent River and at Joint Base Lakehurst in New Jersey which tested a new hook design for the F-35C. An initial series of land-based trials in 2010/11 found the arrestor hook was not sufficiently damped and was often skipping over the arrestor cables due to its

The aircraft appears, on face value at least, suited to carrier life.

proximity to the aircraft’s rear-set main landing gear, and this resulted in a redesign which included a stronger fuselage mounting point and a reprofiled hook to better snag the cable.

The new hook is said to have a flatter bottom and a sharper leading edge, which allows it to better catch a low wire. But the redesign has also led to concerns that the sharper leading edge may damage the wires, so this is likely to be a key assessment point of the DT trials.

A second series of trials, DT-2, is planned for the end of the next northern summer, and DT-3 will follow in early 2016. Each trial will see the aircraft’s envelope and operating environment expanded, and the aircraft subjected to more and more realistic operational scenarios and rates of effort. The F-35C is then scheduled to make its first operational carrier deployment in 2018.

Of particular interest will be the ability of the F-35C’s low observable coatings and panel fit tolerances to withstand the rigours of life aboard an aircraft carrier for an extended deployment lasting several months. Maintenance, fuelling and arming of aircraft is all conducted in tight and confined spaces aboard ship, and the aircraft are subjected to constant salt spray, the stresses of arrested landings and catapult launches, and a much greater potential for knocks and bumps from ground support equipment.

The day after the two aircraft trapped aboard Nimitz, catapult launch trials commenced. Of interest were the toed-in rudders of the F-35C for launches, in much the same way as the Hornet and Super Hornet. This has the effect of moving the aircraft’s centre of pressure aft as it accelerates along the runway to help rotate the nose if the rear stabilisers don’t have sufficient authority. As with the Hornet and Super Hornet, the F-35C pilot appears to be ‘hands off’ during the launches, instead allowing the aircraft’s flight control system to configure the jet for a positive rate of climb off the catapult.

Initial cross-wind launches and approach tests commenced on November 7 where the ability of the aircraft to remain stable in these conditions as well as in the wake turbulence from the Nimitz’s island would be assessed.

Reports that elements within the US Navy have been lobbying for additional Super Hornets to be acquired instead of the much-delayed F-35C have been a constant in recent years. The Super Hornet is well known and understood, is very cheap to operate, is still very capable and has a well laid-out spiral upgrade program ahead of it, and there remains considerable doubt over the resilience of a single-engined stealth aircraft aboard a carrier.

But the initial success of the DT-1 trials where the F-35C has demonstrated its stability and reliability should send a clear message to the US Navy that the aircraft appears, on face value at least, suited to carrier life. This is illustrated by the fact that, after four days of the DT-1 cycle, the two aircraft had completed 55 catapult launches, 84 planned touch-and-go landings, and 57 arrested landings, with no ‘bolters’ or failures to catch the arrestor wire.

While these events were conducted in benign weather conditions, they are encouraging nonetheless.