FAA Federal Aviation Regulations (FARS, 14 CFR)

Each control system which relies on electrical and electronic means for normal operation must:

(a) Have the control system description, the percent of available power or trust controlled in both normal operation and failure conditions, and the range of control of other controlled functions, specified in the instruction manual required by §33.5 for the engine;

(b) Be designed and constructed so that any failure of aircraft-supplied power or data will not result in an unacceptable change in power or thrust, or prevent continued safe operation of the engine;

(c) Be designed and constructed so that no single failure or malfunction, or probable combination of failures of electrical or electronic components of the control system, results in an unsafe condition;

(d) Have environmental limits, including transients caused by lightning strikes, specified in the instruction manual; and

(e) Have all associated software designed and implemented to prevent errors that would result in an unacceptable loss of power or thrust, or other unsafe condition, and have the method used to design and implement the software approved by the Administrator.

[Doc. No. 24466, 58 FR 29095, May 18, 1993]