- Recent Articles
P&W Engines Summer 2005
Download PDF Version
PW530A Fuel Manifold
— Ken Kuchenreuther
Do you have fuel nozzle leaks? One tell-tale sign is fog coming out of the engine after shutdown. Over the years there have been several bulletins addressing seal problems in the nozzle area. Historically, they have been category 6-“address when you have access to the part.”
However, at the end of 2003, SB 30249 came out as a category 3- “recommended compliance within 150 hours.” Citation SL550-73-04 also transmitted the Pratt & Whitney bulletin to the public. Pratt & Whitney 530 engines from SN DA0497 to DA0517 were the only engines addressed in these service bulletins.
If you would like to contribute an idea for this publication, or if you would like more information about this subject, please contact me at 269.969.8400 ext. 8486.
Service Bulletin 30295
— Ken Kuchenreuther
Pratt & Whitney has recently issued Service Bulletin 30295 indicating a problem with some select engine’s first stage low pressure turbine blades. The subject PW535A engine serial numbers are: DCO264, DCO275, DCO277, DCO282, DCO291, and DCO297. It is Pratt & Whitney’s recommendation that this be accomplished within the next 300 flight hours. If you have any questions about this, please contact me.
More on PW545A Interfacing
— Ken Kuchenreuther
This article includes some helpful hints for anyone involved with a Citation 560XL. In the power junction box, located inside the tailcone access door, there are two Electronic Engine Control interface boards, NZ020 and NZ021. Their location is indicated on the power junction box cover. These boards are very difficult to troubleshoot, but suspect problems with one or both of the boards if the engine is not operating normally and isn’t transferring to manual mode. For example, the right engine going to flight idle after start.
We have published two other articles on this issue in past editions of this publication. Here is an excerpt from one, “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 configuration 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.”
If you would like more information about this subject, please contact me at 269.969.8400 ext. 8486.
( Return to top )
