774、如果安装了报警器面板,解释一下它是如何工作的

549、if the probes touch each other ,they can become demagnetized

548、If the indications do not clearly show that a fastener is loose, make a red line across the head and the adjacent material.

547、If the circuit breaker opens, de-energize circuit.

546、If the airplane has a built in auxiliary power unit, describe it and explain how it fits in with the electrical system.

545、If the airplane experiences repeated failures of ta pump at one location, there may be debris in the case drain line, case drain hose or case drain hose quick disconnect that cannot be flushed by accomplishing this procedure.

544、If the air intake flap is not serviceable, do the deactivation procedure of the air inlet valve.

543、If one or more blades are missing make an entry in the engine logbook

542、If it is possible that the temperature values will be more than the permitted limits, decrease the power.

541、If either of these devices is installed explain whether it is required equipment.

540、If an engine fire detection system is available.describe, give principle of operation, and explain how to use it.