P&W Engines Spring 2004

• More Tips on PW545A Interface
• Fuel Manifold Inspection / Replacement
• Installation of Front Fan Case Assembly Vibration Dampener Ring

More Tips on PW545A Interface

— Ken Kuchenreuther

As outlined in the recent special edition of this publication (archives can be accessed at www.DuncanAviation.com), the Electronic Engine Control is constantly considering various airframe configurations for its calculations. This is done through the NZ020 and NZ021 EEC interface boards. This article will examine the squat switch (WOW) and two associations with the engine.

When the aircraft is on the ground, the squat switch relays its arrangement through the EEC interface board via an optical isolator that then hands the message off to the EEC. The EEC then processes flight or ground idle for engine usage and sends the illumination requirement on to the "gnd Idle" annunciator. We recently had the challenge of troubleshooting a scenario where the "gnd Idle" annunciator and engine ground idle were remaining on in flight. One "gnd Idle" annunciator is fed by both EECs making troubleshooting more confusing. Pilot input on what idle was doing in flight on each engine helped the process. The solution in this case was replacement of the NZ021 EEC interface board to obtain system normalization. Other electrical problems could have been in wiring, EEC, squat switch, connections, etc.

For more information on interfacing please contact Ken Kuchenreuther at 800.525.2376.

Fuel Manifold Inspection / Replacement

— Ken Kuchenreuther

Pratt and Whitney has recently released SB #30249 and recommends that it be accomplished at the next aircraft minor within no more than 150 flight hours. Certain serial number fuel manifolds may be contaminated with a corrosive agent and need replacement. The following engines are affected: PW530A engines from and including DA0497 to serial DA0517; PW535A engine serial DC0013 and engines from and including DC0194 to serial DC0226; PW545A engines serial number DB0312, DB0414, DB0442 and engines from and including DB0599 to DB0626, except serial number DB0621. Fuel manifold serial numbers are listed in the SB and should be checked before ordering parts or completely disassembling the engine. Pratt and Whitney offers financial assistance for affected operators until 30 November 2004 per Commercial Support Program Notification #A03008.

For more information please contact Ken Kuchenreuther at 800.525.2376.

Installation of Front Fan Case Assembly Vibration Dampener Ring

— Ken Kuchenreuther

Pratt and Whitney SB 302481 has just been released from CSU (Controlled Service Usage). Pratt and Whitney recommends that this SB be done at the next access to the fan case. The bulletin applies to Post-SB30219 fan case assemblies PN 30J2503-01 with no cracks only. If cracks are found on front fan case, it should be replaced before complying with this bulletin. The bulletin consists of bonding a rubber vibration ring to the outer diameter of the front fan case to reduce vibratory stresses on the case. A Commercial Support Program Notification #A03013 supplies financial assistance to applicable engines until 30 November 2005. This applies to affected PW545A engines.

For more information on this issue please contact Ken Kuchenreuther at 800.525.2376.

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