VII. Stability augmentation system (SAS)
(a) If a SAS is used, the reliability of the
SAS must be related to the effects of its failure.
The occurrence of any failure condition which
would prevent continued safe flight and landing
must be extremely improbable. For any failure
condition of the SAS which is not shown to be
extremely improbable –
(1) The helicopter must be safely
controllable and capable of prolonged
instrument flight without undue pilot effort.
Additional unrelated probable failures affecting
the control system must be considered; and
(2) The flight characteristics
requirements in Subpart B of JAR–29 must be
met throughout a practical flight envelope.
(b) The SAS must be designed so that it
cannot create a hazardous deviation in flight path
or produce hazardous loads on the helicopter
during normal operation or in the event of
malfunction or failure, assuming corrective action
begins within an appropriate period of time.
Where multiple systems are installed, subsequent
malfunction conditions must be considered in
sequence unless their occurrence is shown to be
improbable.
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