• CF34 Servicing
• Oil
• Variable Geometry
• Fuel Filters
• Thrust Reverser Tracks
• Starter & IDG
• Summary

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CF34 Servicing

— Bill Walker

Many operators have general servicing of engines done in-house, which is a good idea for several reasons. First, it saves the company money and secondly, the mechanic comes to know the engine very well, so he will be the first to know if something needs attention between scheduled open cowling inspections. Below is a short list of servicing and preventative maintenance tips.

Oil

Checking the oil, believe it or not, seems to be a big problem. When should the oil be serviced? Always service hot. The General Electric Maintenance Manual states 15-45 minutes after shut-down, basically enough time for the oil to stabilize. NEVER service when the engine is cold or after extended downtime without first motoring the engine. A 600 hour inspection requirement is to sample the engine oil, specifically to do an acidity check. The “in thing” now is to use the Ti-Tan Kit. It’s a self-contained kit which is very easy to use and inexpensive. Acid level over 1.5 mg KOH/g requires the oil to be changed. When changing oil, remember to drain the accessory gearbox. Do the leak check 1 qt low and top off with the oiler when the engine is hot.

Variable Geometry

Sloppiness is the biggest issue when lubing the variable geometry. Some of the stages are difficult to reach and just spraying in the general area will result in a messy overspray. Remember, any wetness can be mistaken later for a leak. Use WD- 40 spray and assemble straws long enough to reach each stage and spray just enough to do the job. For the stages where the rodends can be reached, work the oil into the bearings and then clean overspray. For accessible stages, use a rag behind the rod ends to catch overspray.

Fuel Filters

Changing fuel filters can be messy. Two 1-gallon containers can help. Pull the drain plug and drain the filter bowl into one of the containers. Put the plug back in and change containers. Pull the plug back out and break the filter bowl loose. Once the packing seal is broken and you hear air sucking, stop turning the bowl out. Let the fuel drain into the other container. After it stops, reinstall your drain plug and finish removing the filter bowl.Works every time. Remember to manually actuate the bypass every time the filter is removed.

Thrust Reverser Tracks

Lubing the thrust reverser tracks incorrectly can result in the TR jamming. The maintenance manual tells you to clean the tracks and then apply the lube. Although not required, the ideal way to lube the pylon tracks is to remove the TR. If this isn’t possible, fabricate an applicator from a small paint brush taped to a stick or a piece of rag on a stick. Spray the lube right on the applicator and with the TR manually deployed, run the applicator through the tracks until an even coat is applied. Just spraying the lube into the track can result in too much lube and when the TR is operated it can pack the lube until the TR jams. This same technique can be used on the main tracks even though they are easily accessible.

Starter & IDG

Service both when cool to the touch. Service the starter even if oil appears in servicing port. Remember to vent IDG before removing the standpipe plug.

Summary

These are all easy in-house tasks that result in significant savings. To discuss this topic or other CF34 engine issues, contact Bill Walker or Gerry Riffle at 800.228.4277.

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