Pre-closing diligence
Maintenance-program records readiness review for acquisition teams
This review tests whether the maintenance-program status offered in a transaction is actually supported by the program documents behind it. An acquisition or technical due diligence team commissions it between the letter of intent and closing, while there is still leverage to demand corrections. The reviewer traces the task due list back to the approved program revision, checks each escalation and bridging analysis for an approval that covers this aircraft, and flags intervals that quietly outlived the basis that authorized them. Findings arrive as a document-referenced exception register the deal team can price, negotiate, or require the seller to cure.
When this review is needed
- A purchase agreement is in negotiation and the seller's maintenance-program status will set part of the price.
- The aircraft moved between operators and its due list was bridged onto a different program more than once.
- Escalated intervals appear in the status report and the diligence team has not seen the approvals behind them.
- Financing depends on a records condition and the lender wants the program basis verified, not asserted.
The problem
Deal teams inherit a maintenance-program status report built by someone else's CAMO under someone else's assumptions. Escalations approved years ago, bridging analyses from a prior transition, and program revisions that never reached the planning system all sit underneath the numbers. Under a closing deadline, nobody on the buy side has time to pull each source document, so the status gets accepted at face value and priced as if it were proven.
What gets reviewed
- Approved maintenance-program revision applicable to the aircraft, matched against the revision the status report cites
- Escalation approvals for every interval that departs from the baseline program
- Bridging analyses from prior operator transitions and their approval trail
- Task due list sampling to confirm intervals, thresholds, and last-done values trace to source records
- Program-basis history across operators, including any period where the basis is undocumented
- Open items and carried-forward exceptions disclosed by the seller against what the documents show
Scope this review
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What gets validated
- Every interval on the sampled due list matches the approved revision or carries a specific escalation approval
- Each bridging analysis names this serial number and was accepted by the authority or CAMO that governed the transition
- Last-done dates and hours on sampled tasks agree with the work packages that accomplished them
- Program revisions referenced in the status report exist in the delivered document set
- No task interval relies on an approval that expired or applied to a different operator's program
Evidence normally required
- Current maintenance-program status report and task due list
- Approved program revisions and the transmittals that put them into effect
- Escalation approvals and reliability data supporting extended intervals
- Bridging analyses from each operator transition in the aircraft's history
- Work packages or task cards for the sampled last-done entries
Common discrepancies
- Intervals still running at an escalated value after the aircraft left the operator whose reliability program justified it
- A bridging analysis referenced in the status report that the seller cannot produce
- Due-list entries citing a program revision newer than any approval in the document set
- Last-done values keyed from a summary sheet rather than the closing work package
What is at stake
A due list that cannot be tied to its approved basis surfaces after closing, when the buyer's CAMO tries to load the aircraft onto its own program. Tasks come due earlier than the model assumed, bridging work is repeated at the buyer's cost, and any records condition in the purchase agreement is already spent. What would have been a negotiating point becomes an operating expense.
Move from findings to resolution
Move from findings to a documented resolution path.
How the work runs
Scope the sample
Select due-list tasks weighted toward escalated intervals, bridged tasks, and high-cost items.
Trace to approvals
Pull each sampled interval back to the program revision, escalation, or bridging analysis that authorizes it.
Verify last-done evidence
Match last-done dates and utilization on sampled tasks to the work packages that closed them.
Issue the exception register
Deliver findings ranked by transaction impact with a cure path for each.
What the buyer receives
- An exception register keyed to individual tasks and the documents that fail to support them
- A source map linking each element of the program status to its approving record
- A cure list sequenced for the seller, split into pre-closing items and priced carry-overs
Who uses the output
- Deal leads deciding what to demand, price, or walk away from before signature
- The buyer's CAMO preparing to bridge the aircraft onto its own approved program
- Lenders and insurers relying on the records condition in the financing documents
How the work fits into the transaction or program
This review runs inside technical due diligence, alongside the AD, LLP, and logbook workstreams, and feeds the exception schedule attached to the purchase agreement. After closing, its source map becomes the starting point for the buyer's own bridging analysis, so nothing verified during diligence has to be re-proven at induction.
Jurisdiction-specific considerations
Program-basis expectations differ between regimes. An aircraft operated under 14 CFR Part 121 or 135 carries an operator-specific approved program, while an EASA aircraft's due list ties back to a CAMO-controlled maintenance program under Regulation 1321/2014. A transaction moving the aircraft across regimes needs the review to state which authority's approval each escalation and bridge actually rests on.
Regulatory limits
The review examines documents and their consistency. It does not approve a maintenance program, grant or extend an escalation, perform a bridging analysis, or determine that the aircraft is airworthy. Those decisions remain with the operator, its CAMO, and the responsible authority.
What this review does not cover
- Physical inspection of the aircraft or borescope of engines
- Negotiating the purchase agreement or its records conditions
- Building the buyer's post-closing maintenance program
Specific to this review
- Escalation approvals are usually tied to one operator's reliability program, so they rarely survive a change of operator even when the interval keeps running in the planning system.
- A status report can cite the correct program revision while the planning system still runs intervals loaded from an older one; only sampling the due list against the revision exposes this.
- Bridging analyses are the most commonly missing document in maintenance-program diligence because they were produced during a past transition and never filed with the continuing records.
- Sellers can cure program-basis findings cheaply before closing; the same findings cost the buyer a re-bridge and early task accomplishment afterward.
- The due list drives near-term maintenance cash more directly than any other record set, which is why program exceptions move price faster than most records findings.
Sources
U.S. Government (eCFR). Air carrier maintenance recordkeeping and retention requirements under Part 121.
U.S. Government (eCFR). Maintenance recordkeeping and retention requirements for Part 135 operators.
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.
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.
Frequently asked questions
Can this run in parallel with the rest of technical due diligence?
Yes, and it usually should. The program review shares source documents with the AD and logbook workstreams, so running them together avoids duplicate data-room requests and lets exceptions be cross-checked, for example an escalated interval whose supporting work package also closes an AD.
Relevant glossary terms
Related pages
Where this fits
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