Index integrity
Testing the digital records index that a data-room package rests on
Every data-room package rests on a digital records index, and this review tests that index directly, early in the diligence timetable. A buy-side specialist samples index rows against the uploaded scans, checking that each file opens, can be searched, belongs to this aircraft, and matches the description the row gives it. Weak indexing is quantified rather than guessed at. The transaction lead receives exception entries plus a defect-rate picture that shows whether the room can be trusted at scale.
When this review is needed
- Spot checks in the room keep opening documents that fail to match their index descriptions.
- The seller digitized paper records recently and the room is the first outside test of that migration.
- Thousands of files must be assessed in weeks and the team needs to know if the index can carry that load.
- OCR quality is visibly poor and searches are silently missing responsive documents.
The problem
Diligence timetables assume the index works: type a task number, an AD reference, or a part serial and the record appears. When rows are mislabeled, scans are image-only, or file names encode a defunct archive scheme, every search silently under-returns. Reviewers do not see what they missed, and the confidence of a clean search becomes the most dangerous artifact in the room.
What gets reviewed
- Statistical sample of index rows opened and scored against their uploaded files
- Text-searchability of scans measured, distinguishing OCR text layers from bare images
- Aircraft identity checks confirming sampled files belong to this serial number
- File naming and folder conventions read for internal consistency and orphaned uploads
- Search-recall probes using known references such as AD numbers and part serials
Scope this review
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What gets validated
- A sampled row's description, date, and document type agree with the file it opens
- Searches for references known to exist in the archive actually return them
- Scans carry a usable text layer rather than image-only pages
- No sampled file carries another aircraft's registration, serial, or work-order identity
- Files present in folders but absent from the index are counted and characterized
Evidence normally required
- The room's index export in its native spreadsheet or database format
- Bulk access to the underlying files, or a seller-provided sample set if bulk access is refused
- A seed list of known references for recall testing, drawn from status lists in the room
- Any migration or scanning documentation the seller can share about how the archive was built
Common discrepancies
- Image-only scans in exactly the oldest folders, where OCR was skipped to save migration cost
- Index descriptions inherited from box labels rather than from the documents inside
- Orphan files uploaded outside the index that contain material evidence nobody can find
- Recall failures where a known AD reference exists on paper but never in a search result
What is at stake
A defective index skews every downstream review at once. AD checks, LLP traces, and binder verifications all inherit its blind spots, so gaps ship through diligence looking like clean results. Post-closing, the buyer pays twice: once to discover the misses and again to re-index the archive under their own control.
Move from findings to resolution
Move from findings to a documented resolution path.
How the work runs
Design the sample
Stratify index rows by folder, age, and document class so the score reflects the whole archive.
Score the rows
Open each sampled file and grade match, legibility, searchability, and aircraft identity.
Probe recall
Run seeded searches for references the room must contain and log what returns.
Set the method
Report defect rates and exceptions, and state where search can be trusted and where it cannot.
What the buyer receives
- A measured defect rate for the index by folder and document class
- Exception entries for the diligence schedule where index failures hide material records
- A recall-test report listing the seeded references and what the room returned
- Guidance on where manual page-turning must replace search for the rest of diligence
Who uses the output
- Diligence leads recalibrating how much manual review the room actually requires
- Transaction managers deciding whether index quality itself becomes a negotiated item
- The buyer's records team scoping the re-indexing effort they inherit at closing
How the work fits into the transaction or program
The index review runs first among the data-room checks, because its result sets the method for all the others. If recall is strong, the AD, LLP, binder, and review-file checks proceed search-led. If it is weak, those reviews shift to folder-by-folder reading, and the timetable is corrected before it fails quietly.
Jurisdiction-specific considerations
FAA guidance in AC 120-78 addresses electronic recordkeeping and what makes a digital record acceptable, and AC 43-9C describes the content maintenance records must preserve; together they frame what a digitized archive must still be able to show. EASA-regulated holders carry equivalent obligations through Regulation 1321/2014. An index that cannot reliably retrieve records undermines the holder's position under either regime.
Regulatory limits
This is an information-quality assessment of a seller's data room. It does not certify the archive as compliant electronic recordkeeping, does not approve any system, and makes no finding about the aircraft's airworthiness. Records retrieved through the index still need substantive review on their own merits.
What this review does not cover
- Re-scanning, re-OCRing, or repairing the seller's archive
- Substantive technical review of the documents the index points to
- Assessment of the seller's records software beyond the exports it produced
Specific to this review
- Recall failure is invisible without seeding: a search that returns nothing looks identical whether the document is absent or merely unindexed.
- Migration projects commonly OCR the newest decade and skip the earliest boxes, so index quality degrades with document age, opposite to where diligence risk concentrates.
- A file-name convention change midway through an archive usually marks a vendor change in the scanning project, and defect rates differ sharply on each side of it.
- Duplicate uploads inflate apparent completeness; two hundred copies of one release certificate can mask two hundred absences.
- Sampling beats exhaustive checking here: a scored sample of a few hundred rows predicts room-wide reliability well enough to steer the whole diligence plan.
Sources
Federal Aviation Administration. FAA acceptance criteria for electronic recordkeeping systems and electronic signatures.
Federal Aviation Administration. FAA guidance on making and keeping maintenance records and acceptable recordkeeping practices.
European Union / EASA. Continuing airworthiness, maintenance records, CAMO responsibilities, and the airworthiness review process in the EASA system.
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
Why review the index instead of just reviewing the records?
Because the index decides which records the team ever sees. On a room of tens of thousands of files, substantive review is search-led by necessity; if recall is broken, effort lands on the wrong documents. An index score early in diligence buys certainty for every later check at low cost.
Bulk file access was refused. Can the index still be assessed?
Partially. A seller-provided sample can be scored for match and legibility, and recall can be probed through the room's own search tools. The report will state the limits of what the method could see, which is itself useful in negotiating fuller access.
Relevant glossary terms
Related pages
Where this fits
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