Self-testable architecture for overspeed limitation and cutoff systems when the turbojet stops

摘要

A hydraulic fuel control unit (100) for an aircraft engine comprises means (14, 2, 16) for controlling cutoff on stop and cutoff on overspeed of a fuel flow transferred by an output (1) to the engine injectors. A logic module (140) controls the position of a state switch (121, 143) into a test position or a normal position. The state module is managed such that the operation of the overspeed module can be tested each time the system is started on the ground. The architecture of the hydraulic unit (100) is such that operation of the cutoff on stop can be tested during each landing. Correct operation in the overspeed test and in the cutoff on stop test is observed by detecting a difference between a control value (153) of an allowable fuel flow that depends mainly on the engine speed, and a real flow value detected by sensors (22).