Final answer:
According to title 14 of the CFR, an engine may be granted zero time by the manufacturer if it has been completely rebuilt or restored to factory specifications. This means the engine is considered new and hasn't been used.
Step-by-step explanation:
According to title 14 of the CFR, an engine may be granted zero time by the manufacturer if it has been:
- completely rebuilt
- restored to factory specifications
In this case, the term "zero time" refers to the fact that the engine is considered as new and has not been used or operated since the rebuilding or restoration process.