THE VIRGINIAN-PILOT
Copyright (c) 1996, Landmark Communications, Inc.
DATE: Saturday, August 31, 1996 TAG: 9608310366
SECTION: FRONT PAGE: A3 EDITION: FINAL
SOURCE: BY DALE EISMAN, STAFF WRITER
DATELINE: WASHINGTON LENGTH: 52 lines
Navy investigators believe they have found the cause of an F-14 Tomcat crash in February that killed two airmen and led to restrictions on the use of afterburners in about 130 of the jets.
Fixing the problem, a service spokesman said Friday, may require no more than the replacement of inexpensive turnbuckles that help secure the combustion chamber inside each of the ``B'' and ``D'' model Tomcat's General Electric-built jet engines.
The roughly 200 ``A'' model Tomcats, the oldest F-14s in service, have Pratt & Whitney engines and have not been restricted in using their afterburners.
Though additional tests remain, a Navy spokesman said that engineers now believe the elliptical shape of the turnbuckles in the GE engines impeded the flow of air around the combustion chamber toward the rear, afterburner section.
That caused excessive heat to build up around the combustion chamber and may have triggered the ignition of oil and fuel that seep from parts within the engine as part of its normal operation, the spokesman suggested.
To solve the problem, the Navy plans to install rounded turnbuckles in some engines and to begin testing them Sept. 20. If the engines perform as expected, the service would begin installing new turnbuckles in all ``B'' and ``D'' model engines.
The service could do the work on about 15 of the planes per month, a spokesman said.
Four F-14s have crashed this year. Two of the crashes have been attributed to pilot error.
The turnbuckle is the suspected culprit in a Feb. 18 accident in the Pacific off Southern California. After that crash, the Navy barred pilots of ``B'' and ``D'' model Tomcats from lighting their afterburners when flying under 10,000 feet.
The Navy is preparing to install a new digital flight control system that effectively will prevent all F-14 pilots from attempting maneuvers that are judged beyond the Tomcat's capabilities. That will cost about $80 million.
The service also is installing a new pressure sensor near the engine air intakes of the ``A'' model Tomcats. The sensor will warn the pilot if an engine is in danger of stalling because of lack of air.
The Navy says the restriction on use of afterburners in ``B'' and ``D'' model Tomcats has had a negligible impact on readiness. Pilots have been instructed that they can use the afterburners in a combat situation or other emergency.
Oceana Naval Air Station in Virginia Beach is home to most of the Navy's F-14 squadrons and will host all 12 squadrons by the end of next year.
KEYWORDS: F-14 ACCIDENT AIRPLANE U.S. NAVY by CNB