Engine Cycles

[PlaneJohn]

With regard to jet engines what is the definition of a cycle? I had to take a crewmember up to do his PIC landing currency and when filling out the flight logs for the airplane the other pilot and I were in disagreement as to what is considered a cycle. Would a cycle be considered a start, application of take off rated thrust and a shutdown? Or would it be considered just an application of takeoff rated thrust? When filling out the flight log I think it should be 3 landings and 1 cycle for each engine, the other crewmember thinks it would be 3 landings and 3 cycles for each engine. Which is correct?

Thanks
PJ

 

[TransMach]

Each manufacturer has their own definition of a cycle. Sometimes they include fractions of a cycle for maintenance runs that don't achieve takeoff thrust. Best to ask your head of maintenance what your engine's definitions are.

TransMach

 

[bizjet800]

A former chief pilot said a cycle is a start with at least 5 minutes at full thrust--so one cycle virtually everytime you fly--but not if you just start up and taxi around.

I have always logged it that way, even when training with multiple legs. Doesn't mean its correct.

 

[LJ45]

Each manufacturer has their own definition of a cycle. Sometimes they include fractions of a cycle for maintenance runs that don't achieve takeoff thrust. Best to ask your head of maintenance what your engine's definitions are.

TransMach

Ditto....and that is why airplanes come with all those books

 

[PlaneJohn]

Thanks guys. I kinda thought the same thing in that it is manufacturer specific. Looks like I'm calling Pratt.

 

[TransMach]

Cycle Definition

Thanks guys. I kinda thought the same thing in that it is manufacturer specific. Looks like I'm calling Pratt.

EXCELLENT, grasshopper! You will find knowledge in your quest.

TransMach

PS .. Thanks for the support LJ45 ... I just hate the "Well in the '40s or when I was a chief pilot we used to do ... "

 

[VGerect]

Gotta agree with TransMach

I'm flying a Citation now and have all the Cessna Customer Support numbers programmed into my cell phone. It's much better to get an answer from the horses mouth at Cessna than the horses a$$ back at the hanger.

Come to think of it, I should have a phone number for Pratt also....Do post after you talk to them.

 

[NCherches]

Any word on this?

 

[PlaneJohn]

I can only speak to the Beechjet as it is manufacture specific with regard to flight/engine cycles. Per the BE400A maintenance manual a cycle is defined as: an engine start, followed by application of full or partial power, a retraction and extension of the landing gear, and a shutdown. So in regard to my particular situation 3 touch and goes would only be considered one cycle due to the absence of a shutdown. So, in our airplane flight log it would be recorded as 3 landings and 1 cycle for each engine. Hope this helps.

 

[NCherches]

Anyone know about Citations? (Bravo P&W's if it matters)

 

[falcon20pilot]

PlaneJohn's quote is identical to the description in the Beech King Air maintenance manual for Pratt PT6's, so it would seem that it is determined by the manufacturer regardless of the engine they install.

I would find the maintenance manual for the aircraft, which your service people should have and should provide to you. It should be the one with the check lists they follow for inspections and has all of the definitions in it.

 

[tracearabians]

I believe JSSI uses engine starts as cycles .

 

[avbug]

Cycles are manufacturer-specific, as Transmach stated. Some manufacturers go with a thermal cycle (the basic definition of a cycle), while others go with percentages of power and temperatures reached, as well as duration. For some manufacturers, if one doesn't shut down the engine, multiple power-ups are still considered one cycle. For other manufacturers, cycles accrue by percentages, dependent on engine operation.

 

[PilotKitch]

From what our maintenance guy gets from Gulfstream stream it is a take-off and landing or gear up then gear down. 3 touch and go's = 3 cycles...