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Goshawk gets first go on fixed cat

NAVAIR Release

Press Release Number: EPX200307171

Release Date: 7/17/2003

By JIM JENKINS Public Affairs

NAVAIR PATUXENT RIVER, MD-The TC-7 catapult launched its first aircraft - a T-45 Goshawk - July 1, since unscheduled depot level maintenance on the system's launch valves forced its closure in February.

In the middle of a snowstorm this winter, NAVAIR Lakehurst aircraft launch and recovery equipment specialists joined with the Pax team in a two-day effort to remove the launch valves from the catapult system. The Pax crew, led by ABE2 Kevin Nowell, removed 48 deck plates, each weighing approximately 700 pounds to get to the launch valves. The team had to remove 1,164 bolts just to get the deck plates out.

"We just replaced our low-loss launch valves here," said ABEC Mark Newman, TC-7 maintenance chief. "We had some major failures earlier in the year."

The main cause for the deterioration of the valves was that the catapult here has frequent cycles of heating and cooling, unlike a shipboard catapult which stays hot while at sea for six months, according to Newman. The Pax catapult gets hot eight hours before a launch.

The launch happens and then cools down until the next test that requires a launch. Heat causes the metal in the catapult to expand, then the cooling causes the metal to contract. The frequent expansion and contraction causes metal fatigue and eventually failure.

"Some of the large steam head bolts, like three-inch bolts, were snapping off," Newman said. "The temperature ranges up and down all the time cause the bolts to start snapping, and they've been in here since '88, I believe, roughly, and that's not a long service life for that valve."

The valves were all sent to Lakehurst, N.J., where the maintenance was performed and they were returned about three weeks ago.

The TC-7 team conducted the interim certification two weeks ago, shooting numerous no-loads to test all the data and make sure the catapult performance was up to par. A no-load is a test shot of the catapult with no aircraft, weight or load.

Starting July 1, going into July 2, phase two of certification for the catapult was conducted which consisted of launching three aircraft, a Goshawk, F/A-18C Hornet and an F/A-18F Super Hornet, representing different weight values. Several launches of each aircraft went off uneventfully, as expected, completing the certification and putting the TC-7 catapult back in business.

"It was good teamwork on all parts [Lakehurst and Pax teams] working with each other to get the cat back up," said Lt. j.g. Mack Wafford, TC-7 site officer.

Pilots and engineers from NAWCAD's Carrier Suitability office organized the aircraft launches from the TC-7 catapult performing phase two of the certification. The aircraft were empty except for the Goshawk, which carried an instrumentation box underneath to measure landing loads. The Carrier "Suit" team is doing a similar test, checking launch loads, at the end of July aboard USS Ronald Reagan (CVN 76).

"It's measuring arresting hook loads," said Charlie Trost, Carrier Suitability engineer. "Reagan has a new type of arresting gear, so we'll get hook loads when [Carrier Suit pilots] trap, launch bar tow force and longitudinal acceleration for the catapult and arresting gear. How much it's decelerating and accelerating."

Reagan has the Mod 4 arresting system whereas all the other carriers have either a Mod 3 or Mod 3plus system, according to Trost. The catapult system is the same, though. Also unique to Reagan is that it is going to be the only Nimitz class carrier to have only three arresting wires. The other eight ships have four.

The TC-7 catapult, operated and maintained by Air Test and Evaluation Squadron 23, is a linear piston-type steam engine used to launch airplanes up to 85,000 pounds gross weight. Similar catapult systems were used in USS Forrestal class carriers, such as the USS Independence (CV 62), decommissioned in 1998. Initially completed in 1954, the TC-7 catapult underwent a $1.6 million modernization project in 1986 and a $200,000 upgrade in 1993, and is considered the Navy's premier aircraft carrier suitability test facility.