CF34 Engines Fall 2007

• Subtle Throttling and Maneuvering Saves Engine Maintenance Costs
• General Electric CF34 Engine – Fan Disc Update

Subtle Throttling and Maneuvering Saves Engine Maintenance Costs

— David Bogart

Several years ago, I was given sage advice from one of our engine customers. Although his name has escaped me, his wisdom has not.

This gentleman explained to his entire Flight Department that if they eased their throttle movements and made lower angled takeoffs, they would save wear-and-tear replacement costs at inspections. Slow throttle movements and lower angled takeoffs subject the turbine assemblies to less stressful shifts in temperature and rotational forces, preserving more of the life of the turbines and various other engine components.

A few pilots began putting his suggestions into practice and indeed discovered, over the years, substantial savings in fewer required parts replacements due to stress wear, at subsequent inspections. As a result of adopting this throttle-finessing practice, the pilots and mechanics significantly reduced the Flight Department’s cost of operations.

This practice could apply to the operation of any model of gas turbine engine. With escalating maintenance costs and the complexity of aircraft maintenance, less aggressive engine power lever management and maneuvering at all phases of flight makes good sense for every flight department that wants to limit engine wear and keep expenses under control.

General Electric CF34 Engine – Fan Disc Update

— Andy Divine

Service Bulletin CF34-BJ 72-A0212 Fan Disk Arc-Out Inspection

The above Service Bulletin was released by General Electric on March 7, 2007.

Due to an anticipated fan disc shortage as a result of operators complying with this SB, General Electric asked CF34 business jet operators to refrain from complying with this inspection until the bulletin became mandatory.

However the demand for replacement discs has not been as high as previously expected. Initial inspections of fan discs through the inspection process revealed only a small percentage of discs required rework and an even smaller number of discs required replacement.

All CF34 business jet operators are free to schedule this inspection as necessary. ­ For more information about these and other turbine engine technical issues, contact Duncan Aviation turbine engine expert, Bill Walker, at 800.228.4277, ext 4269.

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