Apache Helicopters Grounded

(CBS)  The Army has grounded its fleet of attack helicopters for the third time in two years.
The tail rotor blades on all 742 Apache helicopters will be inspected before the choppers are allowed to fly again. The action follows an incident in which the tail rotor assembly fell off an Israeli Apache.

Last December, the fleet was grounded to fix a flaw in the flight control system. And in November 1999, the Army halted flights to replace tail rotor bearings or transmission parts.

The tail rotor on the Israeli helicopter came apart during a flight on June 11. The aircraft landed safely at an Israeli air base. An investigation is under way to determine the cause of that incident.

The Apache is an attack helicopter armed with rockets, laser-guided missiles and a 30mm cannon. Apaches saw service against Iraq's forward air defenses in the Gulf War and was deployed in Albania during the NATO action in Kosovo, but not used in the conflict.

Made by Boeing and acquired by the Pentagon at a cost of over $14 billion for the fleet, the Apache has had its share of problems lately, many of them also involving the tail rotor:

• May 5, 1999: The Army ordered a 24-hour stand down for Apache helicopters following a deadly crash in Albania that killed two U.S. pilots, the second accident in the Balkans in a two-week period.
  
  
• November 8, 1999: The Army ordered inspections of all Apaches helicopters and the grounding of those that had a type of tail rotor bearing linked to an earlier crash in Alabama so the bearing could be replaced.
  
  
• February, 2000: CBS News reports claims that the Apache's backup control system, or BUCS, has a history of coming on unexpectedly and sending unintended signals into the flight control system.
  
  
• December 15, 2000: The Army grounded the entire fleet as a precaution after discovering a flaw in a key component of the flight control system: the tail rotor swashplate assembly. That is a component on the rear of the Apache that manipulates the tail rotor in accordance with the pilot's foot pedal movements to direct the helicopter right or left. A similar system on the main rotor moves the chopper vertically.

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