NCO.IDE.A.135 Flight crew interphone system

GENERAL

(a)The flight crew interphone system should not be of a handheld type.

(b)A headset consists of a communication device that includes two earphones to receive and a microphone to transmit audio signals to the aeroplane’s communication system. To comply with the minimum performance requirements, the earphones and microphone should match the communication system’s characteristics and the flight crew compartment environment. The headset should be adequately adjustable in order to fit the pilot’s head. Headset boom microphones should be of the noise cancelling type.

(c)If the intention is to utilise noise cancelling earphones, the pilot-in-command should ensure that the earphones do not attenuate any aural warnings or sounds necessary for alerting the flight crew on matters related to the safe operation of the aeroplane.

HEADSET The term ‘headset’ includes any aviation helmet incorporating headphones and microphone worn by a flight crew member.