Why F-35 pilots have the jitters
A host of problems plague the US military's newest jet fighter, the F-35, but one of the simplest yet most troublesome is identified in a new government audit as unreadable "symbology."
The problem exists inside a small item at the heart of what makes the F-35 the world's most sophisticated aircraft - if only it could be made to work. Namely, the pilot's helmet visor. On the world's most advanced, fifth-generation military aircraft, the visor is meant to be much more than a sun shield. It is supposed to do wondrous things.
Acting like a small, see-through movie screen, it is designed to display data showing how the plane is performing, where enemy targets are, and which weapons the pilot can use to handle them. As the pilot swivels his head, the display is meant to adapt, creating a direct link - as in a science-fiction movie - between the pilot and the aircraft's unprecedented computing power.
The visor is, according to the Government Accountability Office's latest annual report on the F-35's development, "integral to the mission systems architecture." In other words, the plane was more or less designed around the unique capabilities of that fancy helmet appendage.
Just one problem: It doesn't work. In flight tests, the visor's "symbology" has evidently been unreadable, because the plane itself has been bouncing up and down in the air more than expected. The effect is probably like trying to read an e-book while riding a bicycle along a boulder-strewn path.
"Display jitter," the GAO report says in a footnote, "is the undesired shaking of display, making symbology unreadable ... [due to] worse than expected vibrations, known as aircraft buffet."
Unfortunately for the plane's designers, jitter and buffeting are only part of the problems undermining the visor's use. The others are a persistent delay in displaying key sensor data - making the visor symbols outdated as the aircraft streaks through the air at speeds up to 3000kmh - and an inability to show night vision readings properly.
So what's the big deal? It's just a visor. Well, the GAO report says "these shortfalls may lead to a helmet unable to fully meet warfighter requirements - unsuitable for flight tasks and weapons delivery, as well as creating an unmanageable pilot workload, and may place limitations on the [F-35's] operational environment."
In short, if the visor doesn't work, the plane may not be able to do all the impressive things that the Pentagon is spending more than US$1.5 trillion (NZ$1.9 trillion)- over the next 30 or so years - to make it do. The GAO said this alarm was sounded by the programme officials interviewed by its investigators.
A new visor is under development, at an estimated cost of just US$80 million (NZ$101 million), so the US Air Force may have a backup if the original visor's kinks cannot be worked out. But according to the GAO, the alternate visor won't be as capable. An Air Force spokesman did not respond to a request for comment, but DODBuzz.com quoted the F-35 programme director in March as promising that the helmet troubles are "being addressed."
The director, Vice Admiral David Venlet, told a defence conference that the plane was just having "normal teething problems."
A few things went well for the F-35 programme last year. A version being made for the Marines, capable of short takeoffs and landings, "performed better than expected" in flight tests. And the Air Force was able to double the number of test flights it performed the previous year. The volume of changes made to engineering drawings of the plane's components every month - even while the plane is in early production - has started to decline.
But there wasn't a lot of other good news in the report. Although the program was extensively restructured by senior Pentagon officials last year, by adding many millions of dollars and stretching out key deadlines, it still managed to meet only six of its eleven objectives for the period. Many of these goals were administrative. Among the uncompleted tasks: an interim upgrade of the plane's software and a redesign of its tailhook.
The plane has had no difficulty being launched by catapults, a key prerequisite for its use by the Navy aboard aircraft carriers. But so far, it has not been able to use its tailhook to catch a cable and stop suddenly - which is also, well, crucial for operations on an aircraft carrier. Generally speaking, Navy pilots need a place to land when their missions are complete.
Venlet has called the tailhook troubles "a damping-bouncing issue" that could not have been foreseen. It is being redesigned, but the GAO warns that "other aircraft structural modifications may also be required." The discovery of cracks in the plane's bulkhead, an upright wall in its fuselage, will require costly repairs, and other parts are showing unexpectedly early signs of wear. Flight tests so far have shown "different structural loads than predicted," the GAO disclosed, a sure sign that unplanned work lies ahead. "Aircraft reliability and parts shortages" contributed to testing shortfalls last year.
In an October report, a special testing team of Air Force, Navy, and British officers found shortcomings in "aircraft handling characteristics and shortfalls in maneuvering performance," according to a GAO summary of the officers' report. Besides flagging the troubled helmet, they complained about poor management of spare parts supplies, excessive repair time for the plane's delicate radar-absorbing skin, and "poor maintainability performance."
The Pentagon has increasingly been at loggerheads with the chief contractor, Lockheed Martin, over the work ahead. Already, cost overruns on four early production contracts have totalled US$1 billion (NZ$1.9 billion), with the government on the hook to pay just over two-thirds this amount. But Uncle Sam's ambition is still to buy 365 of the planes (out of 2457) at a cost of $69 billion ($NZ87 billion), before completing so-called developmental flight tests - the spins in the sky that are needed to make sure everything is operating properly.
Until those tests are finished, the GAO said - repeating a theme the government watchdog has sounded for the past seven years - the F-35 program is "very susceptible to discovering costly design and technical problems after many aircraft have been fielded." The auditors expressed worry as a result that the Pentagon may not be able to afford the program in its current form and urged that it conduct a study now of the impact of future budget cuts.
In a written reply, Deputy Assistant Secretary of Defense David G Ahern said the Pentagon conducts such studies all the time, but "does not believe there is value" in making them public. He also said that any such analysis would have to consider the impact of any cuts in a broad context, including the "industrial base," the size of the existing fighter fleet, and Washington's deals to sell the plane to foreign allies.