Deferred maintenance
Pilatus PC-12 deferred maintenance records review
This review confirms that a Pilatus PC-12 deferred maintenance log holds only items with a valid deferral basis and that cleared items were actually closed. It suits an owner, buyer, or manager who needs the open-defect position to be honest before a sale or a program handover. The work checks each deferment against its MEL or CDL reference, its category time limit, and the corrective entry that cleared it for the single-engine turboprop. You receive an exception list of deferrals that overran or closed without evidence, a source map from the log to each item's basis and clearance, and a closure plan for the tail.
When this review is needed
- A PC-12 deferred maintenance log has grown and no one has confirmed the open items still hold a valid basis.
- A buyer wants the true open-defect position before pricing the aircraft.
- Deferrals were carried under an MEL and the aircraft is moving to an operation with different relief.
- Cleared items need checking to confirm they closed with real corrective evidence.
The problem
A deferred maintenance log is only useful if every open line has a live basis and every closed line actually shut. On an owner-managed PC-12, a defect deferred under an MEL category can quietly overrun its time limit, an item can be carried with no reference to the relief that permits it, and a clearing entry can mark something complete without the corrective work being recorded. The log then reads as controlled while carrying items that either should have grounded the aircraft or never truly closed.
What gets reviewed
- Each open deferral matched to its MEL or CDL reference and category
- Category time limits checked against the date each item was deferred
- Clearing entries confirmed to carry corrective evidence, not just a closure mark
- Repeated deferrals of the same defect identified as a recurring problem
- Open items screened for any that should not have been deferrable at all
- Handover impact where the receiving operation's relief differs from the current one
Scope this review
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What gets validated
- Every open deferral cites a valid MEL or CDL item and the correct repair category
- No open deferral has run past the time limit its category allows
- Each cleared item shows the corrective action that closed it, not only a sign-off
- Items that recur across multiple deferrals are flagged as an underlying defect
- No item is carried on the log that the MEL or CDL does not permit to be deferred
Evidence normally required
- The deferred maintenance log and its open and closed entries
- The MEL and CDL applicable to the aircraft and its operation
- Corrective-action records for cleared items
- The technical log or discrepancy sheets feeding the deferrals
- The receiving operation's MEL where a handover is planned
Common discrepancies
- An open deferral that has run past its category time limit
- A clearing entry that marks an item closed with no corrective record
- The same defect deferred repeatedly, pointing to an unfixed root cause
- An item carried on the log that the MEL does not permit to be deferred
What is at stake
An overrun deferral means the aircraft was operated outside the relief it relied on, which is a finding a buyer or an auditor will not overlook. A clearing entry with no corrective evidence leaves a defect that looks closed but may still be present, and an incoming operator with different MEL relief may inherit deferrals that its own operation does not permit.
Move from findings to resolution
Move from findings to a documented resolution path.
How the work runs
List every open item
Pull the current deferred maintenance log and separate open items from cleared ones.
Test the basis and clock
Confirm each open item cites a valid MEL or CDL reference and sits within its time limit.
Verify the clearances
Check that cleared items carry corrective evidence, not just a closure mark.
Flag and plan
List overrun, unsupported, and improper deferrals and set the correction needed for each.
What the buyer receives
- An exception list of overrun, unsupported, or improperly deferred items
- A source map from the log to each item's MEL or CDL basis and clearance
- A closure plan naming the correction or record needed to settle each open item
Who uses the output
- Owners and operators carrying an honest open-defect position on the aircraft
- Buyers pricing the true state of open items before closing
- Records teams reconciling the log before a program handover
How the work fits into the transaction or program
The deferred-maintenance review gives the true open-defect position that feeds a redelivery binder, an export package, or a program handover, all of which have to state what is still open. Settling the log before those milestones means the open items are known and dispositioned rather than surfacing mid-transfer.
Aircraft-specific considerations
PC-12s move between owner-managed private use and commercial charter, and the MEL relief available differs sharply between those operations, so a deferral valid under one can be impermissible under the other. The review scopes each open item to the operation the aircraft is under and to the one it is moving toward, which is where deferrals most often become non-compliant on this type.
Jurisdiction-specific considerations
MEL and CDL structures and the relief they grant differ between FAA and EASA operations, so a PC-12 changing register or operating rule may find that deferrals carried under one framework are not deferrable under the receiving one, and the review notes those items explicitly.
Regulatory limits
The review confirms the deferred items hold a valid basis and that clearances are supported. It does not authorize a deferral, clear a defect, or determine that the aircraft may be dispatched with any open item.
What this review does not cover
- Performing the corrective maintenance behind a deferred item
- Authorizing or clearing a deferral
- Any dispatch or airworthiness decision on an open item
Specific to this review
- An overrun deferral means the aircraft flew outside its relief, which is a harder finding to explain than an open defect properly carried.
- A defect deferred over and over signals an unfixed root cause the log alone hides behind fresh deferral entries.
- MEL relief that differs between private and charter use makes PC-12 deferrals a frequent handover problem.
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
How does this affect a move from private to charter operation?
MEL relief under a charter operation is often narrower than under private use, so some items validly deferred today may not be deferrable once the aircraft is on the charter certificate. The review flags those items so they can be closed before the operation changes rather than after.
Relevant glossary terms
Related pages
Where this fits
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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.