Manufacturer begins replacing CRJ700/900 fuel ejectors as Transport Canada issues airworthiness directive
Bombardier has begun the replacement of high-time fuel ejector pumps in CRJ700 and CRJ900 regional jets after five failures caused by cavitation. Transport Canada last week issued an airworthiness directive (AD) requiring fuel-quantity checks for each flight, or alternatively prohibiting use of the centre tank, until the ejectors are replaced.
The Canadian manufacturer says it is working "aggressively" with fuel-system supplier Intertechnique to release a new ejector design with retrofit parts in August. Each aircraft has two primary fuel ejectors and a single failure will not cause an unsafe condition, says CRJ700/900 fleet leader Martin Elliot.
The AD requires ejectors exceeding 2,750 flight hours to be replaced within 750h; those with 2,750h or less to be replaced before 3,500h; those exceeding 3,500h to be replaced within 180 days; and says no ejectors are to exceed 4,500h. For an aircraft with either ejector above 2,000h, operators are to perform a centre tank fuel-quantity check before or after each flight. Alternatively, fuel in the centre tank can be prohibited.
Bombardier says the ejector failures were caused by a thinning of material as a result of cavitation. A February AD instructed operators to check for longitudinal cracks in the ejectors causing fuel leakage into the centre tank.
The fix for an earlier fuel-system AD relating to fuel-line cracking caused by vibration is part of Bombardier's second reliability improvement modification programme (RIMP-2) for the CRJ700/900. Proof installation of the modification package on the first customer aircraft began at Bombardier West Virginia Air Center maintenance facility last week.
RIMP-2 will be launched by mid-May and completed within a year, says Elliot. The modifications will bring the fleet-wide despatch reliability, now 98%, up to an industry-standard 99%. Bombardier's newly opened Tucson, Arizona regional-aircraft heavy maintenance centre will also install the modifications, while Adria Airways in Slovenia will perform the work for European CRJ700/900 operators.
To improve CRJ700/900 reliability in the short term, Bombardier plans to release a series of overnight modifications, Elliot says, with free parts and labour.
US Airways has taken delivery of the first of 25 CRJ700 Series 701 regional jets on order. The 70-seater has been delivered to wholly owned subsidiary PSA Airlines.
GRAHAM WARWICK / MONTREAL
Source: Flight International
