Hard Time is basically a maintenance program that determines when a component etc. requires replacement, overall, servicing etc. It has been replaced on larger aircraft by reliability based programs such as "On Condition", and "Condition Monitoring".
Some information on this subject is available in FAA Advisory Circulars at
--on the left side click on Regulation & Policies then click on Advisory Circulars. In the search box type in "Hard Time" or "Soft Time". This will bring up a few AC's that pertain to maintenance and certification
For specific information you should contact your local governing authority.
Hi Clun,
When the hard time threshold is reached, the part/component must be removed from service mandatory.In case of soft time, you must remove the part from service when accessible. E.g. when a part in an engine has a softtime of 10000 hrs, you must not remove the engine from service to be disassembled and remove/overhaul the part when the engine reaches 10000 hrs and when there is no other reason to remove it; but when the engine is removed for any other reason, at e.g. 12000 hrs, you must remove the part with the soft time of 10000 hrs is exceeded.
I hope this answers your question.
Rgds avio
