The C at Sea: The F-35 Aboard the USS Dwight D. Eisenhower
After a successful initial ship trial (Development Test-I (DT-I)) at the end of last year, the joint team of U.S. Navy, Lockheed Martin, Northrop Grumman and BAE Systems personnel who make up the F-35 Integrated Test Force (ITF) is back at sea on the USS Dwight D. Eisenhower (CVN 69) to continue testing the capabilities of the F-35C.
For DT-II, the ITF based out of NAS Patuxent River, Maryland, will continue to expand the flight envelope, launching and recovering aircraft loaded with internal weapons while evaluating their flying and handling qualities under various wind conditions and catapult settings. To find out more about the F-35C testing at sea, we sat down with Jim Gigliotti, a Navy Veteran whose 28-year Naval Aviation career included aircraft operations and test tours of duty as well as Command of the Aircraft Carrier USS Harry S Truman. He gave us a few more details about DT-II.
A standard airframe for a fighter jet is made out of the lightest but strongest materials possible. But for the F-35C, those standard materials won’t cut it. Carrier-based operations are very unforgiving to an aircraft because of the roughness of arrested landings and catapult takeoffs. Aircraft not specifically designed for ship operations would be unable to cope with the harsh carrier environment and would not survive the loads and stresses put on the vehicle. So the airframe, or the “skeleton,” of the F-35C contains a significant amount of titanium, one of the strongest metals available.
As a result, the F-35C weighs 5,500 pounds more than an A variant, which is designed to perform conventional takeoff and landings – on land. The B-variant (which is also capable of ship operations) contains titanium as well, but because the short takeoffs and vertical landings it performs aren’t as stressing as arrested landings and catapult takeoffs, not as much titanium is necessary.
In addition to needing a sturdier airframe, the F-35’s stealth coatings must be capable of standing up to the harsh and sometimes unpredictable weather conditions in an at-sea environment. So how does the F-35’s stealth coating hold up?
“For almost the last decade, we’ve been putting panels that are made the same way F-35 panels are made on legacy aircraft that are deployed at-sea,” explains Gigliotti. “This was meant to check just that – how well do the coatings wear on this aircraft?” In addition, climactic tests have been conducted on the aircraft to ensure it can withstand extreme heat, cold and moisture.
Day to Day: B vs. C
Besides the obvious difference between the way the B and C variants land and takeoff from the ship, there are some key differences in deck operations. First of all, the way the jets are parked is different.
“On the big-deck amphibious war ships that the B-variant will operate from, there’s a set routine on where they park all the aircraft and helicopters. There’s not a lot of room, so you have to be very precise,” explains Gigliotti. On an aircraft carrier, it’s the same basic premise, but the folded wings give a little more flexibility. “Folding the wings are critical to being able to put as many airplanes you can in a very small space. They literally park inches away from each other.”
The Devil is in the Details
Some of the various maintenance and operations testing being conducted are things you might not even think of when you see the jet land on the carrier. For example: every aircraft on the deck needs to be chained down due to the motion of the ship. When your airfield tends to roll and pitch with the waves, you can’t have 29 ton aircraft rolling around free on a flightdeck. So the team will perform various exercises to ensure they can chain the aircraft in certain spots, and that the chains don’t cause any trip hazards or encumber weapons loading or other maintenance operations.
Also during DT-II, the team will perform fit-checks with a Pratt & Whitney F-135 engine to confirm it can fit in the jet shop, an area in the aft part of the carrier’s hangar deck where maintenance occurs.
“You can have all the measurements figured out in advance and in theory it should fit, but this is a check to make 100% certain that the engine can be moved around and manipulated within the jet shop,” explains Gigliotti. In addition, the team will perform a simulated power module swap to ensure that the power module within the engine can be replaced onboard if necessary.
During DT-II, the Joint Precision Approach Landing System (JPALS) will be initially tested to verify that the displays and inertial alignment function are working. This system, which is on both the B and C variants of the F-35, is the next generation precision approach system that provides the pilot with the ability to fly a very precise flight path when landing on an aircraft carrier. Gigliotti explains this advancement:
“With JPALS, the ship and the aircraft will ‘talk’ to each other. JPALS allows the aircraft’s system to register where it is and which direction it’s going in relation to the ship via a radio frequency (RF) signal so the aircraft can correctly align itself with the ship for landing,” explains Gigliotti. “It also adds a ‘Wi-Fi-like’ capability for inertial alignment before flight.”
Eventually, he explains, JPALS will provide the capability for a hands-off approach, meaning the pilot will be able to completely let go of control of the aircraft – literally and figuratively – and allow the jet to land itself on the carrier.