GM1 21.A.307(b)(3) and (b)(4) Meaning of ‘negligible safety effect’

CAA ORS9 Decision No. 48

For the purpose of 21.A.307(b)(3) and (b)(4), when ‘a part or appliance for which the consequences of non-conformity to its design has a negligible safety effect when installed on the product’ is mentioned, it means that any non-conformity of the part or appliance not identified by the installer that conducted the specific verification activities mentioned in 21.A.307 (c):

1. for ELA1 and ELA2 aircraft, at worst:

   1. slightly reduces the operational or functional certified capabilities of the aircraft or its safety margins;

   2. causes some physical discomfort to its occupants; and

   3. slightly increases the workload of the flight crew; and

2. for any other aircraft:

   1. has no effect on the operational or functional certified capabilities of the aircraft, or on its safety margins;

   2. causes no physical discomfort to the occupants; and

   3. has no effect on the flight crew.