Boeing 737 MAX deferred maintenance records review

When this review is needed

• A tail is transferring and any deferral open at handover carries into the receiving operator's exposure.
• A deferment log entry references an MEL item without the category or interval that governs it.
• A deferral shows as cleared but the corrective action that should have closed it is not in the file.
• The operator's MEL differs from the one the receiving party will apply, and open items have to be re-based.

The problem

Deferred maintenance is a controlled way to keep flying with a known open item, but the control depends on every deferral carrying its MEL or CDL basis, its category, and its time limit. A deferral can be logged against an MEL item without the interval it allows, a cleared item can show no corrective action, and an open item can outlive the category limit that governed it. On a tail changing hands, deferrals open under one operator's MEL do not automatically fit the receiving operator's, so an item accepted under one basis has to be re-examined under another.

What gets reviewed

• Each open deferral checked for a valid MEL or CDL basis, category, and time limit
• Cleared deferrals traced to the corrective action that closed them
• Deferment log entries reconciled against the corrective-action records
• Open items assessed against the interval the governing category allows
• Deferrals re-based where the receiving operator's MEL differs from the deferring one
• Recurring or repeated deferrals identified where the same item defers repeatedly

What gets validated

• Each open deferral cites an MEL or CDL item with the correct category and interval
• Every cleared deferral shows a corrective action that closed the underlying defect
• No open deferral exceeds the time limit its category allows
• The deferment log and the corrective-action records agree on what is open and what is cleared
• Items deferred under a prior operator's MEL are re-examined against the receiving basis

Evidence normally required

• The deferred maintenance log for the airframe
• The MEL and CDL in use, with the receiving operator's where a transfer applies
• Corrective-action records for cleared deferrals
• The technical log or defect record the deferrals originate from
• The maintenance program for repeated or recurring deferred items

Common discrepancies

• An open deferral logged without the category or time limit its MEL item requires
• A deferral marked cleared with no corrective action on file
• An open item that has outlived the interval its category allowed
• The same defect deferred repeatedly rather than corrected

What is at stake

An open deferral without a valid basis or within an expired limit is an unmanaged item the receiving operator inherits, which can ground the tail until it is cleared. A deferral marked cleared with no corrective action leaves the underlying defect unaccounted for, and a mismatch between the deferring and receiving MEL means an item accepted before the transfer may not be acceptable after it.

How the work runs

What the buyer receives

• A supported exception list of deferrals lacking a basis, a limit, or a clearance
• A source map tying each deferral to its MEL basis and corrective action
• A plan to close open items and re-base deferrals for the receiving operator

Who uses the output

• Records teams clearing the deferral history before a redelivery or induction
• Receiving operators reading inherited open items into their own MEL basis
• Asset managers pricing the open-deferral exposure a tail carries at transfer

How the work fits into the transaction or program

The deferred-maintenance review reads the open and cleared deferral history against the MEL and CDL basis that governed it, and it feeds the transfer or induction where open items become the receiving operator's exposure. It runs before handover so a deferral can be cleared or re-based while the deferring operator's records are still available.

Aircraft-specific considerations

The 737 MAX carries dense avionics and software, so a deferral can rest on a system whose MEL relief depends on a configuration or a data-load state, which makes the basis worth checking against the recorded configuration rather than reading the MEL item alone. Because the family is operated under varied operator MELs, deferrals open at a transfer are re-examined against the receiving basis rather than carried forward unchecked.

Jurisdiction-specific considerations

The MEL derives from the master minimum equipment list but is operator-specific, and an FAA operator's MEL and an EASA operator's differ in structure and relief, so a deferral acceptable under one may not fit the other, which the review flags for re-basing rather than assuming portability.

Regulatory limits

The review reconciles deferrals to their basis and clearance. It does not grant MEL relief, clear a deferral, or make an airworthiness determination on any open item.

What this review does not cover

• Performing the corrective action behind a deferral
• Granting or approving MEL or CDL relief
• Any airworthiness determination on an open item

Specific to this review

• A deferral is only valid within the interval its MEL category allows, so an open item is checked against its time limit, not just its basis.
• The same defect deferred repeatedly signals a corrective action that never held, which the review surfaces rather than treating each deferral as new.
• A deferral open at transfer has to fit the receiving operator's MEL, so items accepted under the prior basis are re-examined rather than carried forward.

Sources

Frequently asked questions

Relevant glossary terms

Related pages

Where this fits