Deferred maintenance
ATR 72 deferred maintenance and MEL history review
This review reconciles an ATR 72's deferred maintenance log and its MEL and CDL entries against the clearing evidence that should close each one. A records specialist runs it before a transaction, at redelivery, or when the deferral log has grown faster than items appear to clear. It checks deferment entries, the MEL or CDL category each was raised under, the interval each carries, and the corrective action that cleared it, then flags deferrals still open or cleared without evidence. You receive a reconciled deferral position, a list of items open or unsupported, and the source references behind each clearing.
When this review is needed
- The deferral log has grown but the clearing entries have not kept pace, so the open count is uncertain.
- A redelivery requires every deferred item cleared or explicitly carried before handover.
- A buyer needs the MEL and CDL history reconciled to confirm nothing is silently still deferred.
- A deferral was raised under an interval that may have expired without a clearing or extension entry.
The problem
Deferred maintenance is a running obligation with a clock on it, and it fails quietly. An item goes onto the MEL under a category with a repair interval, the aircraft keeps flying, the corrective action happens, but the clearing entry never closes the deferral. Or the interval runs out and no one catches it because the log and the clearing evidence live in different systems. On an ATR 72 in dense regional operation, deferrals accumulate quickly and the volume hides the handful that never actually cleared.
What gets reviewed
- Each deferral in the log matched to the MEL or CDL category it was raised under
- The repair interval on each deferral checked against the date and status it cleared
- Clearing corrective actions traced from the work order back to the deferral they closed
- Deferrals still open at review date confirmed against their remaining interval
- Interval extensions checked for the authority and record the operator's system requires
- Deferrals carried out of a check reconciled to the non-routine or defect record they came from
Scope this review
Tell us the asset, the event, and the evidence in scope, and we will outline a focused first engagement.
Send a representative, redacted record set and we will scope the review.
What gets validated
- Every deferral carries an MEL or CDL category and a repair interval consistent with it
- Each cleared deferral shows a corrective action that closed it within its interval
- Deferrals shown open have remaining interval, not an expired clock
- Any interval extension carries the authorization and record the operator requires
- The deferral log and the clearing evidence reconcile line for line
Evidence normally required
- The deferred maintenance log or deferral register
- MEL and CDL references defining the categories and intervals
- Work orders and corrective-action records that cleared deferrals
- Any interval-extension authorizations on file
Common discrepancies
- A deferral whose repair interval expired with no clearing or extension entry
- A corrective action performed but never linked back to the deferral it closed
- An item on the log with a category that does not match its assigned interval
- A deferral carried out of a check with no origin in the non-routine record
What is at stake
A deferral that expired its interval without clearing or extension is an operation the records cannot support, and it is the kind of finding that stalls a redelivery or a sale outright. An item cleared in fact but not on paper reads as still open to a buyer or auditor, and reconstructing the clearing after the fact means chasing the corrective action across work orders that may not reference the deferral at all.
Move from findings to resolution
Move from findings to a documented resolution path.
How the work runs
Read the log
Assemble the deferral register with each item's MEL or CDL category and interval.
Check the clock
Confirm each cleared deferral closed within interval and each open one still has time.
Link the clearing
Trace corrective actions back to the deferrals they closed across the work orders.
Flag the exposure
List expired-interval and unevidenced deferrals for remediation before handover.
What the buyer receives
- A reconciled deferral position showing what is open, cleared, and unsupported
- A list of expired-interval or unevidenced deferrals with the issue on each
- The source references linking each cleared item to its corrective action
Who uses the output
- Records teams closing the deferral log before a redelivery or transaction
- CAMO and operations leads confirming no deferral is silently past its interval
- Asset managers judging whether open deferrals represent real or paper exposure
How the work fits into the transaction or program
The deferral review reconciles the running obligations that the non-routine and defect records feed into. Its reconciled position closes the open-item question a redelivery or data room has to answer, and any expired or unevidenced deferral routes to remediation before it blocks a handover.
Aircraft-specific considerations
An ATR 72 flying dense regional schedules generates deferrals faster than an aircraft with longer sectors and more ground time to clear them, so the log runs long and turns over quickly. The review weights that volume, and it pays attention to the short-interval MEL categories where the clock is most likely to expire between the frequent turnarounds this operation runs.
Jurisdiction-specific considerations
MEL structure and deferral interval conventions differ between FAA and EASA operating rules, so an ATR 72 changing operator may carry deferrals categorized under one system that need reconciling to the other. The review notes where a deferral's interval or category will need translation for the receiving operator.
Regulatory limits
The review reconciles the deferral records against clearing evidence and interval. It does not clear a deferral, grant an interval extension, or make any determination that the aircraft may operate with an item deferred.
What this review does not cover
- Performing the corrective action that clears a deferral
- Granting or authorizing an interval extension
- Any operational or airworthiness determination on a deferred item
Specific to this review
- A deferral is the one record type with a live clock, so an expired interval is a categorically different finding from a missing signature.
- Corrective actions often clear a deferral without referencing it, so the link has to be rebuilt from the work order side.
- Dense regional turnarounds leave little slack to clear short-interval MEL items, which is where the ATR 72 log expires most.
Sources
U.S. Government (eCFR). Maintenance recordkeeping content and approval-for-return-to-service requirements, including 43.9, 43.11, and Appendix B.
U.S. Government (eCFR). Records an owner or operator must keep, including total time in service, current status of life-limited parts, and AD compliance.
European Union / EASA. Continuing airworthiness, maintenance records, CAMO responsibilities, and the airworthiness review process in the EASA system.
International Civil Aviation Organization. International standards for aircraft operation, including maintenance program and recordkeeping expectations.
Frequently asked questions
What is the most serious kind of finding here?
A deferral whose repair interval expired without a clearing or a documented extension. Unlike a missing sign-off, that represents an operation the records cannot support, and it typically has to be resolved before a redelivery or sale can proceed rather than carried as a paper gap.
Relevant glossary terms
Related pages
Where this fits
Talk to an engineer who has done this work
We will walk through your current state, the records or evidence involved, and a scoped first engagement.
Talk through the aircraft, records, evidence, deadline, and next useful step.