Define "clearance" in the context of gas turbine engines and give an example of a critical clearance parameter.

• A. The gap between a moving blade tip and the stationary shroud (tip clearance); another example is bearing clearance between bearing bore and rotor journal.
• B. The gap between the rotor and casing.
• C. The clearance between the fuel nozzle and the combustor.
• D. The gap between the oil pump gear and housing.

Answer: (A)