WASHINGTON — The Navy and Marine Corps on Friday grounded dozens of their front-line F-A-18 Hornet fighters because of a problem with General Electric Co. jet engines that power them.
The two services said they could not estimate precisely how many of the fighters were being grounded because the "flight restriction" order was directed at engines with a certain amount of wear.
Any Hornet with a GE F-404 engine that has accumulated at least 800 hours of flight time will be affected by the grounding order, the services announced. Each F-A-18 is powered by two engines.
Necessary to Cut Risk
"The flight restriction is necessary to reduce the risk of further aircraft loss due to uncontained titanium fires (in the engines)," the Navy reported.
According to the two services, there are 384 F-A-18s in the operational inventory. The Navy and Marine Corps have more than 1,000 operational and spare F-404 engines, of which about one-third are thought to have reached the 800-hour flight limit.
Navy and Marine units around the world have begun scrutinizing their Hornets to determine how many carry engines affected by the grounding order, one official said. It will probably be several days before that process is completed, "but it is clear that dozens of the planes will be affected," the official said.
The F-A-18 is the Navy's newest jet fighter. Built by the McDonnell Douglas Corp., the plane can be outfitted for either air-to-air or air-to-ground combat, and thus is designed to increase the flexibility of air wings assigned to Navy aircraft carriers.
Prompted by Crashes
Friday's grounding order was prompted by a series of recent incidents and crashes. There have been nine F-A-18 accidents this year and at least three involved engine fires.
Similar problems were reported with Hornets sold to the Canadian air force. Canada temporarily halted acceptance of new F-A-18s earlier this month until modifications were made to the compressor turbine blades of the engines.
Earlier this week, GE acknowledged that compressor turbine blades in the Canadian fighters had shown signs of metal fatigue after they had accumulated roughly 1,000 hours of flight time.
The Navy reported that if the compressor turbine blades--which are made of titanium--break off during flight, they can melt and then ignite, setting off a fire in the entire engine.
Engine Fires Cited
"The F-A-18 has recently experienced difficulties centered around the engine's high-pressure compressor that have caused engine fires, which on three occasions have led to the loss of aircraft," the Navy said in a joint statement with the Marine Corps.
"Solutions have been developed and are in the process of being implemented," the statement said.
For the short term, the Navy said it would attack the problem by coating the inside walls of the engine compressors with a synthetic material that should help contain any heat buildup or fire in the compressor unit.
That effort will probably take about two months, the Navy said.
Bob Salvaucci, a GE spokesman, said Friday that the company would have no immediate comment on the grounding order.