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Pratt & Whitney Service Bulletin A66021: Fuel Filter Bypass Valve Replacement

December 2009


In the November 2009 Duncan Intelligence, we discussed replacement of the fuel filter bypass valve in the PW615F-A engine per SB A63069. At that time, SB A66019 was out and called for inspection of the bypass valve only in the PW617F-E engines. SB A66019 has now been cancelled and superseded by SB A66021, calling for replacement of the bypass valve in the PW617F-E engines also.

P&W Recommendations:

  • If you have more than 25 hours TTSN, P&W recommends you comply with this SB in the next 25 flight hours.
  • If you have fewer than 25 hours TTSN, P&W recommends you comply within the next 50 flight hours.
  • If you inspect the existing bypass valve and it is found out of position (open), then the Fuel Metering Unit must be replaced.

Duncan Aviation Recommendations

We recommend that you comply with this Service Bulletin immediately, possibly avoiding the FMU change.

Commercial Support Program Notification # 1004825R01 has been released by Pratt & Whitney providing parts and labor support for operators.

For questions about this or other Technical issues, contact your Duncan Aviation Pratt & Whitney Tech Reps.