Operating Hours and Flight hours

[udaykish]

Hi,
Can anyone explain me the difference between Operating Hours and Flight Hours and how to convert Operating Hours to Flight Hours?

[smorris]

Operating hours is simply the total hours that the aircraft is operating, which includes start up, check-out, taxi time, wait time in for take-off clearance, and actual flight time. Operating hours is some amount of time greater than the actual flight time (flight hours), which represents actual time the aircraft spends in the air. The actual ratio of flight hours to operating hours can depend on many factors, such as aircraft type, mission length, arrival/departure airport, etc. You need to analyze the mission profile in order to develop a conversion factor.

[udaykish]

Don't you agree that start up, check-out, taxi time, wait time in for take-off clearance, and actual flight time are no.of cycles rather than operating hours?

[smorris]

They are "operating" hours, as well as cycles. In addition, people in the aircraft industry also keep track of "flight" hours.

[sadmemories20]

Operating hours is some amount of time greater than the actual flight time (flight hours), which represents actual time the aircraft spends in the air.

[stevee671]

When I worked in aircraft manufacturing, we only used "flight hours".

During functional system check (prior to first flight of the aircraft) of components and systems, operating time was never factored into the mix. If the component failed during this time it was considered infant mortality and the time was calculated as "zero". Even though the component itself may have had up to 20 to 30 hours "operational time" prior to flight time, it wasn't flying when it failed, so it was considered zero.

If the component failed a post flight operational check, the flight hours were used to calculate the time on the component.

[srivastava]

They are operating hours, as well as cycles.