U.S. Navair Grounds New Hueys, One Cobra
Bettina H. Chavanne chavanne@aviationweek.com
U.S. Naval Air Systems Command (Navair) has issued a temporary grounding bulletin on six UH-1Y Hueys and one AH-1Z Cobra due to extensive damage to the main rotor gearbox on two of the new Hueys.
The problem was identified by pilots mid-flight. "Warning lights indicated chips were present in the gear box of the aircraft," Navair spokesman Mike Welding said. The first time the problem occurred was on April 7. The second incident, on April 24, resulted in grounding all of the aircraft. The two affected UH-1Ys, stationed at Camp Pendleton, Calif., sustained "significant damage" to their gear boxes, which need to be replaced, according to Welding.
Navair and manufacturer Bell Helicopter Textron have determined the problem to be faulty lower roller bearing retainers in the high-speed bearing assembly in the gearbox. However, the investigation is still ongoing. "They know what caused it, they have to determine why," he said. The repairs - which could take up to two months - will be performed at Camp Pendleton.
On first glance, the assessment is that this is a new part that shows it is bad early in its lifecycle, Welding said, since it failed in under 100 hours.
The H-1 program upgrade office still has "enormous confidence in the program," according to deputy program manager Scott Hite. Bell spokesperson Tom Dolney told Aviation Week that two UH-1Ys and a single AH-1Z on the final assembly line and an H-1 in the paint shop will all undergo inspections prior to flight testing.
Bell is under contract to supply the Marine Corps with 349 new helicopters--123 are UH-1Ys and 226 are AH-1Z Cobras. Only last month, Navy Rear Adm. Steven Eastburg, the program executive officer overseeing the H-1 upgrade program, said he was encouraged by what he considers to be improved performance by Bell on the Huey/Cobra program after a host of management problems prompted the Navy and Marines to evaluate other platforms in 2006 (Aerospace DAILY, March 6).
UH-1Y photo credit: U.S. Marines Corps
