Nick.....
Yes, I have direct knowledge.....
I looked up the type certificate for the aircraft, and that has the explanation...It is using the military engine, as you stated. Since this engine is not Type Certificated by the FAA, I guess GE feels they have limited liability exposure with the product. The aircraft is also specifically approved for external load, and firefighting...but....
The 214 was also approved for RHL in the Bell manual. It was a standard category aircraft, with no limitations in the TC that prohibited any operations. Even the TC for the CT7 did not limit the type of missions the aircraft was authorized to perform if the GE engine was installed.
I am not sure of the methods used to develop the military cycle limits for the engine, but have the opinion that RHL was not factored into the program, as other military helicopters that have found their way into the civilian world...
The issue with the cycle lives was not temperature operations of the engine...The issue was rotational speeds of the N1 (compressor) components in the engine. The same old story.....limits developed for 3 to 5 power events an hour.....not 12 to 20 an hour.
The problem GE had was the formulas used for calculation of the cycle lives of the engine that were dependant upon N1 speed would not support operations above 12 power events an hour. Since this engine is basically "on condition", the cycle lives are the only factor requiring engine heavy maintenance actions. GE stated that the effort to revise these formulas to take into account RHL , and gain FAA approval was cost prohibitive....
Also, besides the FAA reporting comment, they stated part support from GE for our aircraft would not exist. Since the only place you could get parts for these unusual engines in the civil helicopter world was GE (Standard Category parts), that screwed us.
The Type Certificate for the S70 can be found at:
http://www.airweb.faa.gov/Regulatory...45?OpenDocumen t
(the above link won't work unless you put a t on the end...)
If you get a chance, look at the airworthiness limitations service bulletin for the CT7 engine...then you can see the difference in the types of continuing airworthiness requirements for the engine.
The only difference I see in these two examples.....GE gets to sell more engines...... and Sikorsky has the most exposure to liability, since their Type Certificate is the only FAA approval for the military engine in the S70..