Deferred items
Deferred maintenance history in the modification-baseline source file
Deferrals are controlled promises to fix something later, and the deferred maintenance log is where a configuration baseline can quietly rot. This review reads that log against the source package in both directions: cleared deferrals are checked for the corrective-action evidence behind the clearance, and open deferrals are checked for valid limit control, category, and authorization. It is carried out by records specialists during a configuration baseline or modification-status effort. The end product is a deferral-level exception list, reconciled with the non-routine register, that drops into the configuration support package.
When this review is needed
- The deferral log shows items cleared by maintenance with no work order or card reference to say how.
- Deferrals attach to equipment installed by modification, and the MEL revision in force predates that modification.
- Category time limits appear to have lapsed on items the log still carries as legitimately open.
- A baseline or lease event requires demonstrating that the open-deferral position is controlled and current.
The problem
A deferral log is written by operations under time pressure and closed by maintenance under different time pressure, and the two halves rarely meet cleanly. Clearances get logged with a date and initials while the fixing work order lives elsewhere; extensions get granted verbally and reconstructed afterward; items migrate between the technical log, the deferral system, and the non-routine register with slightly different identities in each. Assembling a defensible account of what was deferred, for how long, under what authority, and how it ended takes deliberate reconciliation work.
What gets reviewed
- The complete deferral log across the periods the baseline covers, all sources merged
- Clearance evidence for closed deferrals: work order, task card, or non-routine closure
- Category assignment and time-limit arithmetic for every open item
- Authorization trail for extensions, including who granted them and under what provision
- MEL applicability for deferrals on modification-installed equipment
- Cross-walk between the deferral log, technical log entries, and the non-routine register
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 cleared deferral cites the maintenance record that accomplished the fix, and that record exists in the package
- Open items sit within their category limits, with extensions documented rather than implied
- Deferral references resolve to a current MEL item applicable to the aircraft's actual configuration
- Items deferred during modification visits reappear correctly in post-visit logs rather than vanishing
- The same defect carries one identity across technical log, deferral system, and non-routine register
Evidence normally required
- The deferred maintenance log and technical log pages for the review period
- MEL revisions in force across that period
- Work orders and task cards cited by clearances
- The non-routine register for cross-walk
- The modification status report identifying equipment added or changed by mods
Common discrepancies
- Clearances recorded as fixed with no maintenance record anywhere behind the entry
- A category C item extended twice with no documented authority for either extension
- Deferrals raised against equipment the MEL revision on file does not yet cover, because the mod came later
- Items that disappear from the log across a check event with neither clearance nor carry-over
What is at stake
An open deferral past its category limit is an active compliance problem, and a cleared deferral without corrective-action evidence is a defect that may still be on the aircraft. Either finding, surfaced by a counterparty rather than by the operator, damages confidence in the whole continuing-airworthiness operation and tends to trigger expanded sampling of everything else.
Move from findings to resolution
Move from findings to a documented resolution path.
How the work runs
Merge the sources
Build one deferral inventory from the log, technical log pages, and non-routine register, resolving identity conflicts.
Audit the clearances
Trace every closed item to the maintenance record that cleared it.
Test the open items
Check category, limit arithmetic, extension authority, and MEL applicability for everything still open.
State the position
Issue the exception list and the reconciled open position as of the baseline date.
What the buyer receives
- A deferral-level exception list splitting clearance-evidence gaps from limit-control gaps
- A reconciled open-deferral position statement as of the baseline date
- A cross-walk table unifying item identities across the three source systems
Who uses the output
- Configuration managers stating the open-deferral position in the baseline
- CAMO staff correcting limit control and extension documentation
- Transaction and redelivery teams pre-empting counterparty findings on deferrals
How the work fits into the transaction or program
Deferral findings share a border with the non-routine strand, since many deferrals begin life as non-routines, and with the modification-status strand, since MEL applicability follows configuration. The review therefore consumes the verified outputs of both and returns the reconciled open position that the configuration support package states as fact.
Jurisdiction-specific considerations
FAA operations lean on the approved MEL and the recordkeeping duties of 14 CFR 91.417, while EASA operations run deferral control through the CAMO under Regulation 1321/2014, with ICAO Annex 6 setting the frame both systems answer to. Extension authority is the sharpest practical difference between regimes, so the review evaluates each extension against the rules of the registry it was granted under.
Regulatory limits
The review neither clears nor extends any deferral. It makes no judgment on whether a deferral was operationally appropriate, issues no airworthiness finding, and leaves all corrective decisions with the operator and its authority; its product is an evidence-based account of the log's condition.
What this review does not cover
- Rectification of open deferred defects
- MEL revision or amendment work
- Operational decisions about continued dispatch with open items
Specific to this review
- Deferrals raised during a modification visit have the highest loss rate, because the visit's paperwork closes as a package and unresolved items fall between the visit records and the line operation's log.
- An MEL that lags the aircraft's configuration is a structural source of invalid deferrals: crews defer against the item that looks closest, and the mismatch only surfaces under review.
- Clearance-evidence gaps concentrate at line stations, where the fix happens fast and the paperwork reference is the first thing dropped.
- The open-deferral position at a baseline date is one of the few records a counterparty can check against the current aircraft within an hour, which makes its accuracy a credibility signal for the entire file.
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
Why do modification visits complicate deferral records in particular?
Two reasons. Items deferred going into the visit are expected to be worked there, so the log often assumes closure that the visit package does not actually evidence. And the modification itself can change what the MEL covers, so deferrals written afterward may reference items that no longer describe the installed configuration. The review checks both directions across every visit in the period.
Relevant glossary terms
Related pages
Where this fits
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