Is there any value other than basic compliance?
By Joe Hertzler
The Maintenance Cycle
Aircraft go through a cycle of events known as the maintenance cycle, which is made up of four basic components or segments: flight, inspection, corrective action, and modification.
Flight Cycle – Once the aircraft is delivered to the owner for use (either new from the factory or fresh out of maintenance), the flight segment of the maintenance cycle begins. The length of the flight segment can be limited by two factors: scheduled maintenance and/or component failure. It is important to note, however, that the scheduled inspection program for an aircraft is purposely designed to eliminate component failure. As the aircraft is operating in this flight segment, it is accumulating hours cycles and calendar time.
Inspection Cycle – The next segment of the maintenance cycle is the inspection segment. Recurring inspections performed on a scheduled basis are supposed to identify unsafe conditions that, when corrected, ensure safe operation for the intended inspection schedule. The inspection segment is the physical action taken by qualified individuals trained to find defects that have developed as a result of the flight segment(s). An aircraft inspection is required to be performed using a checklist. The obvious purpose of the checklist is to avoid forgetting any portion of the inspection and allow an inspection program to be divided up into a logical and adequate schedule.
The other very common part of the inspection phase is the logbook evaluation or audit. The purpose of the audit is to determine the current status of the aircraft (see AMT Feb. 2001 Issue) and identify any deficiencies in the aircraft’s maintenance records. During the inspection phase all discrepancies found are recorded and it must then be determined what discrepancies are to be corrected.
Corrective Action Cycle – The next segment in the maintenance cycle is the corrective action segment. The corrective action segment is the performance of hands on maintenance (to be performed in accordance with appropriate instructions (see AMT Nov. 2000 issue) to correct the physical defects found and the records deficiencies identified. It is the proper correction of the discrepancies found that determines the airworthiness of the aircraft. If all "airworthiness" issues have been corrected, the aircraft is then approved for return to service. When defects and deficiencies that impact the airworthiness of the aircraft are left undone, the inspection performed is still signed off. However, "a list of uncorrected discrepancies" must be provided to the owner-operator and the aircraft should not be operated until those items are corrected.
Modification Cycle – The fourth and final segment in our definition of a maintenance cycle is the modification segment. Often, an aircraft owner will decide that the aircraft would better fit their needs if it was modified. Modifications are either major or minor in nature as previously discussed. The reason to include the modification segment in the maintenance cycle is the possible significance that modification can have on the inspection segment. According to FAA policy, all major modifications should come with Instructions for Continued Airworthiness or ICA’s. These instructions may include new inspection and/or maintenance requirements that must be meshed into the current inspection program for the aircraft. The two basic FAA methods of approving modifications are STCs (Supplemental Type Certificates) and FAA Field Approvals, the latter of which is getting to be less and less common.
So, we then return to the flight segment and continue the maintenance cycle for the life of the aircraft. Having complete and accurate maintenance records can simply make the maintenance cycle more predictable and much less expensive. Following are some ways that having accurate and complete maintenance records can make a difference.
Understanding the cycle.
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