25.901—Installation.
(a)
For the purpose of this part, the airplane powerplant installation includes each component that—
(2)
The components of the installation must be constructed, arranged, and installed so as to ensure their continued safe operation between normal inspections or overhauls;
(4)
The major components of the installation must be electrically bonded to the other parts of the airplane.
(c)
For each powerplant and auxiliary power unit installation, it must be established that no single failure or malfunction or probable combination of failures will jeopardize the safe operation of the airplane except that the failure of structural elements need not be considered if the probability of such failure is extremely remote.