The Virginian-Pilot April 14, 2012

Navy to explore 'catastrophic' breakdown scenarios

By Kate Wiltrout

Loss of power, or loss of control?

That may be the biggest question facing the team investigating the cause of last Friday's jet crash in Virginia Beach.

The Navy has said the F/A-18D Hornet that hit an apartment complex shortly after takeoff from Oceana Naval Air Station experienced a "catastrophic mechanical malfunction," but a detailed explanation will likely take weeks or months.

Boiled down to the most basic terms, the Navy investigation will try to determine whether the doomed Hornet had a problem with its engines, which stopped generating thrust needed to keep the jet aloft, or experienced failures of its hydraulic system or electronic flight controls, either of which could have rendered the aircraft uncontrollable.

Beyond that basic distinction, things quickly get complicated. Various scenarios could lead to either outcome:

- A ruptured fuel line spews jet fuel into a hot engine bay, which catches fire.

- Birds are sucked into one or both engines.

- A "foreign object" - like a wrench accidentally left inside an engine during maintenance - causes a major malfunction.

- The flight control computers fail shortly after takeoff, forcing the plane into an unfamiliar mechanical backup mode that gives pilots far less control.

- Fan blades fly out of an engine that has catastrophically failed, cutting hydraulic and fuel lines.

The so-called "legacy" Hornet - the precursor to the upgraded Super Hornet, which also flies out of Oceana - is one of the Navy and Marine Corps' longest-serving and most reliable planes. The D model, a two-seat version, entered the fleet in 1987. It's more common in Marine Corps squadrons, which have 92 of the planes; the Navy flies 39 of them, according to Cmdr. Phil Rosi, a Navy spokesman. One of the Navy's highest-profile squadrons - the Blue Angels flight demonstration team - flies the C and D versions of the F/A-18.

Those who've spent time in Hornets sing their praises and talk admiringly of the twin General Electric F404 engines that power them to supersonic speeds. Numerous Navy Hornet pilots - both retired and active duty - said they never experienced an engine malfunction during their careers.

"It's an extraordinary airplane in terms of its resilience," said George Dom, a retired Navy pilot who served as commander of Carrier Air Wing 7 at Oceana and, before that, as commanding officer of the Blue Angels.

Dom, who retired in 2003, said he lost a leading edge flap while flying a Hornet at very high speed and was able to land. And he said he's seen Hornet pilots survive midair collisions and return to base.

One scenario experts and pilots discount in Friday's crash is dual engine failure.

"The reason that Navy planes have two engines is because the odds of two engines failing simultaneously are close to nil," said John Pike, a military aviation expert who runs the website globalsecurity.org. "It would have to be a common failure mode, and one thing the two engines have in common is the fuel system."

Pike theorized that the jet, which belonged to Oceana's training squadron, the Gladiators of Strike Fighter Squadron 106, had a clogged fuel line.

Another possibility, Dom said, is that its electronic control system failed. In that situation, the plane wouldn't respond to attempts to adjust the rudder, stabilators, flaps, or ailerons; a pilot could move the stick in any direction, to no effect. If that happens, the aircraft is said to become "uncontrollable," and when it occurs at an altitude below 6,000 feet, procedures call for pilots to eject.

Between the early 1980s and 2004, the Navy lost 20 F/A-18s due to "out of control flights," according to a Naval Air Systems Command brief.

Investigators will also be searching for evidence of "maintenance malpractice," by combing through the jet's computerized maintenance logs and inventories of tools and equipment. One former commanding officer familiar with mishap investigations said relevant computer files would have been locked down within minutes of the crash to make sure no one tampers with them.

The officers doing the investigation will check reports done by both the front-line maintainers - active duty sailors and contractors - and the quality assurance personnel whose job it is to sign off on each and every repair.

Original Hornets were designed to fly for about 6,000 hours, but frequent deployments since 9/11 have forced the Navy to spend hundreds of millions of dollars on modifications to keep the jets flying longer.

Still, Pike said it was unlikely the investigation would focus on the jet's age.

"Obviously, they're not getting any younger," he said. "But they seem to be aging gracefully. If they were developing a structural integrity problem, anything due to aging, the Navy would have known about it long before now."