APU records by type
Honeywell auxiliary power unit records review
An auxiliary power unit records review confirms that an APU's hours, time-since-overhaul, in-unit life-limited part status, and shop-visit findings agree with the status a deal or return relies on. It is used before a sale, a lease return, or an APU exchange. It reviews the installed unit serial number against the airframe records, the hours and time-since-overhaul position, the service-bulletin embodiment, and the release paperwork for the unit and its replaced parts. You receive a unit-level trace, a list of breaks against the status, and the evidence needed to close each one.
When this review is needed
- An APU is being exchanged or sold separately from the airframe and its hours drive the value.
- A lease return states an APU condition and the time-since-overhaul has to be confirmed.
- An APU was swapped during the lease and the serial number must match the airframe records.
- An operator is placing a unit on hours-based support and the entry status has to be fixed.
The problem
An APU is often tracked on hours rather than flight cycles, and it moves between airframes more freely than an engine, so the unit serial number on the wing and the serial number in the records can drift apart. Time-since-overhaul and the in-unit life-limited part position set what the unit is worth, but those figures usually sit on a one-line status that has not been checked against the shop reports. A mismatched serial number or an unsupported overhaul claim is easy to miss until the unit changes hands.
What gets reviewed
- Installed APU serial number reconciled against the airframe records and the unit on the wing
- Hours and cycle accumulation and time-since-overhaul position
- In-unit life-limited part status with supporting release evidence
- Shop-visit and overhaul findings and the build standard returned to service
- Service Bulletin and modification status applicable to the unit
- Release certificates for the unit and its replaced parts
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
- The installed APU serial number matches the airframe and status records
- Hours and time-since-overhaul are consistent across logbooks and the status list
- In-unit life-limited part status is supported by release documents
- Shop-visit findings reconcile with the parts replaced and the standard returned
- Applicable service bulletins shown as embodied carry accomplishment evidence
- The recorded swap history accounts for every change of installed serial number
Evidence normally required
- APU status list with serial number, hours, and cycles
- Shop-visit and overhaul reports for the unit
- LLP and release certificates for the unit and replaced parts
- Service Bulletin and modification status for the serial number
- Airframe records showing the installed unit and any swaps
Common discrepancies
- An installed serial number that does not match the airframe records after a swap
- A time-since-overhaul figure stated on the summary without the supporting overhaul report
- In-unit life-limited part status unsupported by release documents
- A service bulletin shown as embodied without accomplishment evidence
- A swap recorded on the airframe side without a matching unit-side release
What is at stake
An exchange accepted on a serial number that does not match the airframe records leaves a traceability gap that follows the unit to its next owner. An overhaul claimed without its report can force an early shop visit the buyer did not price into the deal.
How the work runs
Anchor the serial number
Confirm the installed unit serial number against the airframe records and the unit on the wing, then map the swap history.
Reconcile hours and overhaul
Tie hours, time-since-overhaul, and in-unit LLP status to the shop and overhaul reports.
Register breaks
Structure each finding with its source document and whether it sits on the airframe or the unit side.
Map closure
Recommend a closure path and responsible party so the unit can be accepted or driven to resolution.
What the buyer receives
- A unit-level traceability record reconciling serial number, hours, and status
- A swap-history reconciliation between the airframe and unit records
- A list of breaks between the status and the shop and release evidence
- A closure path for each finding with the responsible party identified
Who uses the output
- Asset teams pricing the unit on an exchange or sale
- Continuing-airworthiness teams confirming the installed unit before acceptance
- Records teams reconciling the airframe and unit sides of a swap
How the work fits into the transaction or program
The review supports a sale, a lease return, or an APU exchange by reconciling the unit against both the airframe records and the shop evidence. It feeds the component data room and the discrepancy register for the deal.
Start with a single asset
Start with a single tail and expand once the workflow is proven.
Aircraft-specific considerations
An APU is a serialized rotable that moves between airframes and is usually traded on time-since-overhaul rather than total time. The review treats serial-number reconciliation against the airframe records as a first-order check, because that is where APU traceability most often breaks.
Jurisdiction-specific considerations
A unit released under one authority is not automatically accepted under another. Where the APU has crossed authorities, the trace has to carry release documentation the receiving authority will accept.
Regulatory limits
The review confirms records completeness, consistency, and traceability for the unit. It does not certify the APU, set remaining life for the authority, or make any airworthiness determination.
What this review does not cover
- Physical inspection or test running of the unit
- Re-life or re-certification of the unit or its parts
- Any airworthiness or remaining-life determination
Specific to this review
- An APU is commonly tracked on hours rather than cycles and moves between airframes more freely than an engine, so serial-number reconciliation is a first-order check.
- Time-since-overhaul, not total time, usually sets what a unit is worth on an exchange.
- The serial number on the wing and the serial number in the records drift apart often enough that the swap history is verified explicitly.
- The airframe-side swap entry and the unit-side release are checked against each other, because a swap recorded on one side is frequently missing on the other.
Sources
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.
Federal Aviation Administration. Completion and use of FAA Form 8130-3, Authorized Release Certificate, for new and used parts.
European Union Aviation Safety Agency. EASA authorised release certificate for components, equivalent in function to FAA Form 8130-3.
European Union / EASA. Continuing airworthiness, maintenance records, CAMO responsibilities, and the airworthiness review process in the EASA system.
Frequently asked questions
Why is serial-number reconciliation the first check for an APU?
An APU moves between airframes more freely than an engine, so the installed serial number and the records can drift apart. Anchoring the serial number first keeps the hours and overhaul figures attached to the right unit.
Relevant glossary terms
Related pages
Where this fits
Talk to an engineer who has done this work
We will walk through your current state, the records or evidence involved, and a scoped first engagement.
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