By JAMES DARCY
NAS Patuxent River Public Affairs Department

PATUXENT RIVER NAVAL AIR STATION, MD-The Boeing X-32B Joint Strike Fighter (JSF) demonstrator began flight tests from Naval Air Station Patuxent River June 18, getting airborne for the first time since its May 11 arrival. June 18 also marked the first time the aircraft landed in short-takeoff-vertical-landing (STOVL) mode, touching down at speeds well below conventional stall speed while its vertical engine nozzles provided partial lift.

Dennis "Irish" O'Donoghue, Boeing's lead test pilot for the X-32B, commanded all three of the June 18 flights. "You'll see a lot of smiling faces around here this afternoon," he said after initial post-flight briefs. "We matched our predictions very closely."

Because the X-32B has been fitted with a brand new Pratt and Whitney JSF119-614 engine since its arrival here, the first flight of the week was a basic check of functionality. Subsequent flights focused on converting the aircraft to STOVL flight mode, in which engine thrust is redirected through vertical lift nozzles to augment the lift provided by the wings. This allows the aircraft to be flown at greatly reduced speeds, up to and including a full hover.

On June 19, Lt. Cmdr. Paul Stone, British Royal Navy, took over pilot duties for a series of four test flights. Along with the Marine Corps, the British Royal Navy plans to procure the STOVL variant of the final production JSF.

During earlier flights at Edwards Air Force Base, Calif., the minimum speed the test team attempted in STOVL mode was 180 knots. O'Donoghue expanded the flight envelope June 18 by reducing speeds to 125 knots, and Stone ventured further June 19 with a landing in STOVL mode at just 100 knots. The test team planned additional flights throughout the week.

According to Boeing Flight Test Manager Paul Martin, the coming weeks will see the X-32B complete its first transition from wing-borne flight to fully jet-borne hover flight. The next step will be vertical landings, beginning at Pax River's custom Hover Pit facility. Martin explained that the pit "emulates the out-of-ground-effect environment," meaning that it allows an aircraft to touch down without suffering the complications of near-ground hover flight. Those complications include a suck-down effect that increases sink rate toward the end of the landing sequence, and potential ingestion of hot exhaust gases into the engine intake.

"One of the nice things about this aircraft is that it compensates for (ground effect) automatically," O'Donoghue noted. He said the X-32 is designed to have "level one" flying qualities, meaning that the pilot does not have to work as hard to control the plane. "This is by far the lowest workload cockpit I've ever flown in," he said.

The X-32 is a fly-by-wire aircraft, with a digital flight control system acting as a kind of interpreter between the pilot and the plane's control surfaces. A conventional jet has direct linkages between the external control surfaces and the flight stick and pedals in the cockpit. Depending on what the pilot wants to do, a simple movement of the aircraft may require a complicated set of control surface movements, each of which the pilot must manually direct by changing inputs on the stick, O'Donoghue explained.

By contrast, the fly-by-wire system on the X-32 allows a pilot to make a simple input on the flight stick, then let the plane's computers automatically make the small control surface adjustments needed to carry out the maneuver. Between the pilot-friendly flight controls and the hundreds of hours he's spent in the simulator, O'Donoghue said, he is quite confident in how the aircraft will respond to his inputs.

Of course, it doesn't hurt that he has logged more than 5,000 flight hours in 50 different aircraft during his career. A former Marine Corps AV-8 Harrier pilot, O'Donoghue first came to Pax River in the late 1980s to attend the United States Naval Test Pilot School. After graduation, he went to work at Pax as a Harrier test pilot for the Naval Strike Aircraft Test Squadron, where he also worked on the F-14 Tomcat. After leaving the Marine Corps, he test flew Harriers and other aircraft for the National Aeronautics and Space Administration (NASA) before taking a job with Boeing.

"This has been a big homecoming for me," he said of his return to Pax. "I've been seeing a lot of old friends." This latest stay at Pax River has been a throwback to the good old days in more ways than one, however. "I was at NASA when they announced that the Harriers were all leaving Pax River," he recalled. "We all figured that was the end of (vertical/short takeoff and landing) flight testing at Pax. ... Now, to turn around and have the X-32 here doing STOVL flight tests feels really nice."

He added that Pax River has been able to support both STOVL and X-plane testing without hesitation or hiccups. "The tower controllers and area controllers did a fantastic job with us on Monday," he said. "The support was just absolutely outstanding. Anything we needed to do on the airfield we were cleared to do immediately."

O'Donoghue called this a tremendous year for Pax River; between two JSF concept demonstrators and the VECTOR X-31, Pax has played host to three X-planes in past months. "I think it really establishes Pax as the premier research flight test center in the world," he said.

-USN-