---
title: "Part-145 Maintenance Certification and Records · Avioverse"
description: "The Part-145 certificate of release to service (145.A.50): when a CRS may be issued, the EASA Form 1 for components, and the records that must be kept."
url: "https://avioverse.aero/guides/easa-part-145-certification-of-maintenance-records"
---

# Part-145 Maintenance Certification and Records

The Part-145 certificate of release to service (145.A.50): when a CRS may be issued, the EASA Form 1 for components, and the records that must be kept.

[Dionysis Kefalas](https://avioverse.aero/articles/author/dennis-kefalas) 12 Jun 2026 Updated 21 Oct 2026 6 min read For Part-145 and CAMO staff

Part 4 of 9 in EASA Part-145 Maintenance Organisation Show parts Hide parts

1. 1 [Part-145: The Approved Maintenance Organisation](https://avioverse.aero/guides/easa-part-145-approved-maintenance-organisation)
2. 2 [Part-145 Certifying and Support Staff](https://avioverse.aero/guides/easa-part-145-certifying-staff-personnel)
3. 3 [Part-145 Maintenance Data and Performance](https://avioverse.aero/guides/easa-part-145-maintenance-data-performance)
4. 4 Part-145 Maintenance Certification and Records
5. 5 [The Maintenance Organisation Exposition (MOE)](https://avioverse.aero/guides/easa-part-145-maintenance-organisation-exposition)
6. 6 [Part-145 Tool Control and Calibration (145.A.40)](https://avioverse.aero/guides/part-145-tool-control-calibration-145-a-40)
7. 7 [Receiving Inspection of Aircraft Parts: 145.A.42](https://avioverse.aero/guides/receiving-inspection-aircraft-parts-145-a-42)
8. 8 [Part-145 Approved Supplier List and Evaluation](https://avioverse.aero/guides/part-145-supplier-evaluation-approved-supplier-list)
9. 9 [Part-145 Parts Storage, Shelf Life and ESD](https://avioverse.aero/guides/part-145-parts-storage-shelf-life-esd)

Quotes checked on 24 Sep 2026 against EASA Easy Access Rules for Continuing Airworthiness (Regulation (EU) No 1321/2014) — 2 Sep 2025 revision.

On this page

## Signing off the work

This guide is the Part-145 certificate of release to service, and the records kept with it. The [continuing airworthiness records guide](https://avioverse.aero/guides/easa-maintenance-release-to-service-records) covers release to service from the Part-M side.

## When a certificate of release to service may be issued

[145.A.50 (full rule text)](https://avioverse.aero/regulations/easa/continuing-airworthiness/part-145/section-a-technical-and-organisation-requirements/145-a-50) Certification of maintenance

> (a) A certificate of release to service shall be issued by appropriately authorised certifying
>
> staff on behalf of the organisation when that certifying staff has verified that all the
>
> maintenance that was ordered has been properly carried out by the organisation in accordance
>
> with the procedures specified in point 145.A.70, taking into account the availability and use of
>
> the maintenance data specified in point 145.A.45, and that there are no known non-compliances
>
> which endanger flight safety.
>
> (b) A certificate of release to service shall be issued before flight at the completion of any
>
> maintenance.
>
> (c) New defects or incomplete maintenance work orders identified during the maintenance shall be
>
> brought to the attention of the person or organisation responsible for the aircraft continuing
>
> airworthiness for the specific purpose of obtaining agreement to rectify such defects or
>
> completing the missing elements of the maintenance work order. In the case where that person or
>
> organisation declines to have such maintenance carried out under this point, point (e) is
>
> applicable.
>
> (d) A certificate of release to service shall be issued by appropriately authorised certifying
>
> staff on behalf of the organisation after the maintenance that was ordered has been carried out
>
> on a component whilst it was off the aircraft. The authorised release certificate “EASA Form 1”
>
> referred to in Appendix II of Annex I (Part-M) constitutes the component certificate of release
>
> to service except if otherwise specified in point M.A.502 of Annex I (Part-M) or ML.A.502 of
>
> Annex Vb (Part-ML), as applicable. When an organisation maintains a component for its own use,
>
> the EASA Form 1 may not be necessary if the organisation’s internal release procedures in its
>
> MOE so provides.
>
> (e) By derogation to point (a), when the organisation is unable to complete all maintenance
>
> ordered, it may issue a certificate of release to service within the approved aircraft
>
> limitations. The organisation shall enter such fact in the aircraft certificate of release to
>
> service before the issue of such certificate.
>
> (f) By way of derogation from point 145.A.50(a) and point 145.A.42, when an aircraft is grounded
>
> at a location other than the main line station or main maintenance base due to the
>
> non-availability of a component with the appropriate release certificate, the organisation
>
> contracted for the maintenance of that aircraft may temporarily fit a component without the
>
> appropriate release certificate for a maximum of 30 flight hours or until the aircraft first
>
> returns to the main line station or main maintenance base, whichever is the sooner, subject to
>
> the agreement of the person or organisation responsible for the aircraft’s continuing
>
> airworthiness and subject to that component having a suitable release certificate but otherwise
>
> in compliance with all applicable maintenance and operational requirements. Such components
>
> shall be removed by the time limit provided for in the first sentence of this point unless an
>
> appropriate release certificate has been obtained in the meantime under points 145.A.50(a) and
>
> 145.A.42.

Quoted word for word from Regulation (EU) No 1321/2014, Easy Access Rules for Continuing Airworthiness, 2 Sep 2025 revision.

Point (d) is a component whilst it was off the aircraft. The [components guide](https://avioverse.aero/guides/easa-part-145-maintenance-data-performance) follows that release. Point (f) is 30 flight hours, at a location other than the main line station or main maintenance base.

## The records

Point 145.A.55 uses more than one period. The 3 years in point (a)(3) and the 3 years in point (d)(4) are not the same period.

[145.A.55 (full rule text)](https://avioverse.aero/regulations/easa/continuing-airworthiness/part-145/section-a-technical-and-organisation-requirements/145-a-55) Record-keeping

> (a) Maintenance records
>
> (1) The organisation shall record the details of the maintenance work that is carried out within
>
> the scope of its approval. As a minimum, the organisation shall retain all the records that are
>
> necessary to prove that all the requirements have been met for the issue of the certificate of
>
> release to service, including, if any, subcontractor's release documents.
>
> (2) The organisation shall provide a copy of each certificate of release to service to the
>
> operator or customer, together with copies of the detailed maintenance records that are
>
> associated with the work carried out and that are necessary to demonstrate compliance with point
>
> M.A.305 of Annex I (Part-M) or ML.A.305 of Annex Vb (Part-ML), as applicable.
>
> (3) The organisation shall retain a copy of all detailed maintenance records (including
>
> certificates of release to service) and of any associated maintenance data for 3 years from the
>
> date when the aircraft or component to which the work relates was issued with a certificate of
>
> release to service.
>
> (4) If an organisation terminates its operation, it shall transfer all the retained maintenance
>
> records that cover the last 3 years to the last customer or owner of the respective aircraft or
>
> component, or shall store them in the manner specified by the competent authority.
>
> \[…]
>
> (c) Management system, contracting and subcontracting records
>
> The organisation shall ensure that the following records are retained for a minimum period of 5
>
> years:
>
> (i) records of management system key processes referred to in point 145.A.200;
>
> (ii) contracts, both for contracting and subcontracting, referred to in point 145.A.205.
>
> \[…]
>
> (d) Personnel records
>
> \[…]
>
> (4) Personnel records shall be kept for as long as a person works for the organisation, and
>
> shall be retained for at least 3 years after the person has left the organisation, or after an
>
> authorisation issued to that person has been withdrawn.
>
> \[…]
>
> (g) The records shall be stored in a manner that ensures that they are protected from damage,
>
> alteration and theft.

Quoted word for word from Regulation (EU) No 1321/2014, Easy Access Rules for Continuing Airworthiness, 2 Sep 2025 revision.

Point (a)(3) is 3 years from the date the aircraft or component was issued with a certificate of release to service. Point (d)(4) is at least 3 years after the person has left the organisation, or after an authorisation issued to that person has been withdrawn.

## Next

The procedures a certificate of release to service refers to are in the [Maintenance Organisation Exposition](https://avioverse.aero/guides/easa-part-145-maintenance-organisation-exposition).

## Where to read it yourself

Certification of maintenance is 145.A.50 and record-keeping is 145.A.55 in Annex II (Part-145) of Regulation (EU) No 1321/2014, in the EASA **Easy Access Rules for Continuing Airworthiness**, a free download. Every citation in this guide was checked against the **2025-09-02 revision**.

Educational content, not regulatory compliance advice. Verify against the current regulation text before relying on it.

## In this series

## Frequently asked questions

### Who can issue a Part-145 certificate of release to service?

Appropriately authorised certifying staff issue the certificate on behalf of the Part-145 organisation under 145.A.50(a). They must verify proper completion of the ordered maintenance under the organisation's procedures, taking account of maintenance data availability and use, with no known non-compliance endangering flight safety.

### Can a Part-145 CRS be issued with maintenance work incomplete?

145.A.50(e) permits a certificate of release to service within the approved aircraft limitations when the organisation cannot complete all ordered maintenance. The incomplete work must be recorded in the aircraft's certificate before issue. New defects or incomplete work orders must be raised with whoever is responsible for continuing airworthiness under point (c).

### Does every component maintained for an organisation's own use need an EASA Form 1?

Not necessarily. Under 145.A.50(d), an EASA Form 1 may be unnecessary when the organisation maintains a component for its own use and its MOE provides internal release procedures. That point otherwise identifies Form 1 as the component release certificate, subject to the stated M.A.502 or ML.A.502 exceptions.

### How long must a Part-145 organisation keep detailed maintenance records?

145.A.55(a)(3) requires copies of detailed maintenance records, including release certificates and associated maintenance data, to be retained for three years from the aircraft or component's CRS issue date. The rule separately requires records to be protected against damage, alteration and theft.

## Related

- [EASA Part-145 Explained: The Approved Maintenance Organisation Guide · 4 min](https://avioverse.aero/guides/easa-part-145-approved-maintenance-organisation)
- [Certifying Staff, Support Staff and Personnel under Part-145 Guide · 12 min](https://avioverse.aero/guides/easa-part-145-certifying-staff-personnel)
- [Maintenance Data, Components and Performing the Work Guide · 8 min](https://avioverse.aero/guides/easa-part-145-maintenance-data-performance)
- [The Maintenance Organisation Exposition (MOE) Guide · 6 min](https://avioverse.aero/guides/easa-part-145-maintenance-organisation-exposition)

Written by Dionysis Kefalas. Retired Hellenic Air Force Captain and founder of Avioverse. [About the author](https://avioverse.aero/articles/author/dennis-kefalas)

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