AFGS-87219 Electrical Power Systems, AircraftThis specification establishes the performance requirements and verifications for electric power subsystems EPS for aerospace vehicles, including aircraft, helicopters, and missiles.

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A.3.4 Integrity.

AFGS�87219B APPENDIX A

The integrity program requirements shall be in accordance with MIL-STD-1796 for electronics and MIL-STD-1798 for mechanical equipment and subsystems.

REQUIREMENT RATIONALE (A.3.4)

The integrity of the EPS is one of the factors which contribute to the overall integrity of the total aircraft system. The EPS integrity requirement is established by analyses which allocate the overall aircraft requirement among the various subsystems. The EPS requirement is then allocated among its component parts.

REQUIREMENT GUIDANCE (A.3.4)

Ensure that the integrity requirements for the EPS and its components are compatible with the requirement for the total aircraft. For details of the integrity program see MIL-STD-1796,

AFGS-87249, and MIL-STD-1798.

REQUIREMENT LESSONS LEARNED (A.3.4)

Some aircraft had problems with failures of relays used in controlling subsystems' equipment. When investigated, these Military Secification (MS) relays were found to be all in the normal reliability classes of their specifications. However, for a small increase in purchase price, Established Reliability (ER) class relays could have been used. The ER relays with their adequate life requirements would pay for their higher price in savings of troubleshooting and maintenance time and less aircraft down time.

A.4.4 Integrity.

Compliance with the integrity requirements of 3.4 shall be verified by analyses and tests as follows: .

VERIFICATION RATIONALE (A.4.4)

Subsystem and component analyses and tests are the appropriate means for verifying subsystem integrity.

VERIFICATION GUIDANCE (A.4.4)

Specify the analyses, component tests, laboratory subsystem tests, and installed subsystem tests which are necessary to verify that the integrity requirements are met. See MIL-STD-1796, AFGS-87249, and MIL-STD-1798 for further guidance.

VERIFICATION LESSONS LEARNED (A.4.4)

Integrity must be demonstrated on an early production unit to assure that any design changes can be incorporated early in the program.