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Thursday, April 1, 2004

A Bit of Adhesive Fixes Inlet Rings

by Dale Smith James Careless

Enemy fire isn't the only thing that can keep America's Harrier "Jump Jets" from fulfilling their missions. Sometimes it's something as simple as a nagging engine inlet ring issue. During critical stages of engine operations the intake area is subjected to excessive vibration, causing the inlet ring skin, fasteners, and stiffeners to crack. The cracked material then becomes a foreign object damage risk. The military, along with the Harrier's manufacturer, McDonnell-Douglas Aircraft (now Boeing) have been trying to fix this design flaw since 1983.�

While a number of high-tech solutions had been tried, none of them were able to stand up to the excessive loads put on the area by the Harrier's design. At least not until Dr. Dave Barrett, an airframe technology team leader at Patuxent River Naval Air Station, developed a simple solution based on proven technology. His idea was to simply adhere damping tiles to the inlet rings to reduce the damaging vibration.

"With the results of Dave's studies on damping, we convinced the program office and they invested a small amount of money for us to do some design and verification work," explained Troy Hullander, aircraft structural integrity manager for the AV-8B weapons system. "We modified two aircraft. One aircraft went over to Iraq. It had 120 hours on and the damping tile stuck."

The simple and effective damping fix is now going through additional testing on Harriers flying with the U.S. Marine Corps, Italian military, and the U.K. Royal Air Force. The plan is to begin full fleet implementation as part of the Integrated Maintenance Plan and Trainer-Upgrade Program for Marine Corps Harriers.�

"The small investment made will give us immense returns," Hullander said. "And it will also reduce the readiness problems we've had in the fleet."


Navy Awards Mx Trainer Contract to NLX

NLX, a Rockwell Collins company, has won the U.S. Navy contract to develop a maintenance training unit (MTU) simulator for the Northrop Grumman EA-6B ICAP-III Prowler. The twin-engine, side-by-side two-seat Prowler specializes in jamming enemy radar, radio, and data communications. The ICAP-III (improved capability) version Prowler, which began production in June 2003, incorporates improved detection/reaction capabilities plus new cockpit displays and upgraded internal wiring.

"We have been working with Northrop Grumman on the EA-6B ICAP-III avionics upgrade, so it only made sense for our simulator division to develop this aircraft's MTU," said Allen Kopp, NLX's director of business development. "It will essentially be a complete cockpit interior with full-functional simulated displays and equipment. The idea is that the system can be programmed to display certain fault scenarios, which the trainee mechanic is then charged with fixing. To this end, the MTU will include internal components, many of which can be removed and replaced during the training process."� When completed, the EA-6B ICAP-III MTU will be installed and operated at the Naval Aviation Maintenance Training Detachment at Naval Air Station Whidbey Island, Washington.

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