Text in force at 27-51: from 27-12, effective 2 May 1977.
(a) There must be means to quickly shut off all ignition by the grouping of switches or by a master ignition control.
[(b) Each group of ignition switches, except ignition switches for turbine engines for which continuous ignition is not required, and each master ignition control must have a means to prevent its inadvertent operation.]
42 FR 15045 · Source