A bleed valve installation on some 300 General Electric turbofans powering Bombardier CRJ700/900 and Embraer 170/175 regional jets has caused two engine fires prompting an Airworthiness Directive (AD), Thursday. The offending part is a specific operability bleed valve installed on certain GE CF34-8C and CF34-8E series turbofan engines.
Failure of the valve ring lock fuel fittings can cause fuel leaks in the engine and uncontrolled fire resulting in damage to the aircraft. Of three failures reported, all occurred in CF34-8C engines and two led to fires without injury. The FAA estimates fleet-wide repair costs to total more than $7 million. The FAA estimates the proposed AD will affect 300 engines flying on airplanes registered in the U.S. The agency estimates corrective actions detailed by the AD to take two hours at a labor rate of $85 per hour using $25,000 worth of parts per engine. The FAA is seeking comments with 60 days. The offending vavle that is the subject of the AD apparently becomes flawed over time. Of the two fires caused by the valve's failure, one occurred on takeoff.
The crew responded in that case by shutting down the engine and activating fire extinguishing systems before landing safely. Another fire occurred after landing. In that case, the crew shut off fuel to the engine and taxied safely to the gate. In both cases the aircraft suffered fire damage. Compliance with the AD will require operators to remove the specific valve from service before it acquires 12,000 hours in service since new, or within four years of the AD, whichever comes first. For more details and to comment on the proposed AD, click here.Source; AVweb, Glenn Pew
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