Deferred items
Deferred maintenance history reviewed against the maintenance-control export
This review follows every deferral in the deferred maintenance log through its full lifecycle inside the maintenance-control system: the defect that raised it, the MEL or CDL reference and category it was deferred under, the interval requirements that applied while it stayed open, and the corrective-action work order that closed it. Open deferrals are checked against their category limits as of the transfer date. Maintenance control commissions it before an operator transfer because the receiving side reads the open-deferral list as a bill and the closed history as a credibility test. You receive a lifecycle exception report covering both.
When this review is needed
- Open deferrals will transfer with the aircraft and the receiving operator wants each one's pedigree.
- Audit sampling has already found a deferral closed without a corrective-action record.
- Re-deferral chains have built up on recurring defects and the accumulated intervals are unclear.
- The deferral log and the defect log live in different system modules and have visibly drifted.
The problem
A deferral is easy to raise and easy to close administratively, and the system will happily record both without the corrective work order that justifies the closure. Deferral data spans two modules, the defect log where items originate and the due list where interval controls live, so the log that summarizes them inherits the gaps of both. Recurring defects that get re-deferred each time they resurface build interval chains no single record shows.
What gets reviewed
- Each deferral matched to the originating defect entry in the system data
- MEL or CDL reference and category verified for every deferred item
- Interval or repetitive requirements applicable during deferral confirmed on the due list for the open period
- Closure work orders located, with corrective action and release, for every closed deferral
- Re-deferral chains assembled per underlying defect with accumulated intervals computed
- Open deferrals positioned against category time limits at the intended transfer date
Scope this review
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What gets validated
- No deferral closes without a corrective-action work order and release in the source data
- The MEL reference cited on each deferral existed and applied at the time it was raised
- Interval requirements active during a deferral appear as tasks in the due-list history
- Re-deferral chains stay within the limits that govern the accumulated open time
- The item description on the closure matches the defect the deferral was raised against
Evidence normally required
- The deferred maintenance log for the review period
- Defect-log and work-order history from the maintenance-control system
- The operator's MEL at the revisions in force across the period
- Due-list history covering deferral-driven interval tasks
Common discrepancies
- A deferral closed in the log with no corrective work order anywhere in the system
- A category B item quietly extended past its limit through successive re-deferrals
- A deferral raised against one MEL item and closed against a different one
- Interval inspections required during a deferral that never appeared on the due list
What is at stake
At transfer, every open deferral is priced and every dubious closure is sampled. Items closed without evidence reopen as findings, re-deferral chains that exceeded accumulated limits draw authority attention, and interval inspections that should have run during a deferral but never appeared on the due list are the kind of discovery that turns a records review into a compliance investigation.
Move from findings to resolution
Move from findings to a documented resolution path.
How the work runs
Rebuild each lifecycle
Link every log line to its originating defect, MEL reference, interval controls, and closure record.
Assemble the chains
Group re-deferrals by underlying defect and compute accumulated open intervals against limits.
Test the closures
Verify corrective action and release exist for each closed item, flagging administrative closures.
Schedule the open items
Report open deferrals with limit positions at the transfer date and hand exceptions to maintenance control.
What the buyer receives
- A lifecycle exception report covering open and closed deferrals separately
- Re-deferral chain summaries per recurring defect, with accumulated intervals stated
- An open-deferral schedule for the transfer package with limit positions at the handover date
Who uses the output
- Maintenance control resolving closure-evidence gaps before the counterparty samples them
- The receiving operator's CAMO or maintenance-control desk pricing the open list
- Quality and compliance staff assessing whether any chain warrants self-disclosure
How the work fits into the transaction or program
Deferral history connects the defect log, the MEL, and the due list, so this review typically runs alongside the structural repair and logbook checks that draw on the same modules. Its open-deferral schedule goes straight into the transfer status package, and closure-evidence gaps feed the retrieval effort while system access lasts.
Jurisdiction-specific considerations
MEL frameworks diverge between authorities: FAA operators defer under an MEL authorized through operations specifications, while EASA operators derive theirs from the MMEL under rules tied to Regulation (EU) 1321/2014 continuing-airworthiness oversight, with ICAO Annex 6 as the common backdrop. Category rest intervals and extension authority differ in detail, which matters when a transfer moves the aircraft between the two regimes with deferrals still open.
Regulatory limits
This work audits deferral records. It makes no dispatch or airworthiness determination, does not extend, approve, or revise any MEL item, and does not decide whether a past deferral was operationally justified; it reports what the records support and where they fall short.
What this review does not cover
- Rectification of the defects behind open deferrals
- MEL revision, extension approval, or liaison with the authority on MEL matters
- Operational dispatch decisions past or present
Specific to this review
- Re-deferral chains are the classic audit trap: each link looks compliant in isolation while the accumulated open interval breaks the limit no single record displays.
- Administrative closures concentrate around check inputs, when large batches of deferrals are cleared and the paperwork discipline is at its weakest.
- Because deferral data spans the defect log and the due list, an export missing either module cannot substantiate the log, however clean it looks.
- Receiving operators price open deferrals as immediate rectification cost, so trimming the open list before transfer has direct commercial value.
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
Our deferral log is clean. Why would the source data disagree?
The log records intentions; the defect log and due list record what happened. A tidy log can sit on top of closures with no work order, MEL references that shifted between revisions, and interval tasks that never ran. The disagreement only becomes visible when each line is walked through the modules it summarizes, which is what this review does.
Relevant glossary terms
Related pages
Where this fits
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