scope:

This instruction pertains to equipments for any system or major unit thereof. Systems or units required for training, the requirements for which are determined in accordance with reference (c), are not considered as "spare" within the meaning of this instruction. However, systems or equipments used for training are to be included in arriving at total population on which to base the number of spare equipments which will be procured. Further, this instruction is not applicable to aircraft engine requirements which are covered by DOD Instruction 4230.4 and implemented by reference (d).