AMP interval escalation, a cargo-pod modification and an expiring ARC
A commercial operator flies two Cessna 208B Grand Caravans under Part-M with a contracted CAMO. The aircraft are low-utilisation, about 180 hours per year each. The approved maintenance programme requires a 200-hour/12-month inspection, whichever comes first. The operator wants to move to a 300-hour/18-month interval to reduce downtime and cost. The CAMO's maintenance programme manager proposes to amend the programme internally, citing the manufacturer's Maintenance Planning Document, which contains an escalation paragraph allowing a 25% increase for low-utilisation aircraft, and to issue the ARC on that basis. One aircraft's ARC expires in three weeks. Separately, the operator asks the CAMO to approve a minor modification: installing a non-factory cargo pod. The CAMO holds no Part-21 design approval.
1. Can the CAMO unilaterally amend the approved maintenance programme to 300 hours/18 months? Explain the approval route.
Read the worked answer
No. For a commercial air-transport operator under Part-M, the AMP must be approved by the competent authority. The CAMO may propose an amendment and support it with the manufacturer's escalation paragraph, but it cannot put the change into effect by itself. The escalation must be accepted into the approved AMP; until then, the 200-hour/12-month limit remains. The maintenance programme manager should submit a variation with justification - utilisation, manufacturer's data and reliability - and wait for approval. Issuing an ARC against an unapproved AMP would be a serious finding.
2. Can the CAMO approve the cargo-pod installation? How should the modification be handled?
Read the worked answer
No. The cargo pod is a change to the type design, so it must be classified and approved under Part-21. A CAMO without a Part-21 design approval cannot approve it. A minor modification may be approved by a Part-21 Subpart J design organisation or by the competent authority; a major modification needs a supplemental type certificate or equivalent. A cargo pod on a Caravan is likely major because it affects weight and balance, aerodynamic loads and possibly structure. The CAMO's role is to identify the change, ensure the correct approval is obtained, and record it in the aircraft records before installation.
3. The aircraft's ARC expires in three weeks and the AMP variation has not been approved. What should the CAMO do?
Read the worked answer
The CAMO must complete the airworthiness review against the currently approved AMP before the ARC expires. It cannot issue the ARC on the basis of the proposed 300-hour/18-month programme unless that programme is approved. If the review cannot be completed in time, the ARC expires and the aircraft may not fly. The CAMO should not be pressured by the operator into a premature ARC; it should schedule the review immediately and, if the variation is not approved, review to the existing limits. An extension of the ARC is not a substitute for compliance with the approved maintenance programme.