---
title: "21L.B.171 Investigation — Annex Ib, Initial Airworthiness · Avioverse"
description: "The competent authority of the Member State of registry shall prepare procedures for its investigations, covering at least the following elements:"
url: "https://avioverse.aero/regulations/easa/initial-airworthiness/annex-ib/section-b-procedures-for-competent-authorities/21l-b-171"
---

# 21L.B.171 Investigation

Annex Ib · Regulation (EU) No 748/2012 · EAR revision 27 Nov 2025

IR Implementing rule

## 21L.B.171 Investigation

(a) The competent authority of the Member State of registry shall prepare procedures for its investigations, covering at least the following elements:

1\. evaluation of the eligibility of the applicant;

2\. evaluation of the conditions for the application;

3\. evaluation of the documentation received with the application;

4\. inspections of aircraft.

(b) Upon receiving an application for a noise certificate or a restricted noise certificate, the competent authority of the Member State of registry shall verify whether the aircraft is within the scope established in point 21L.A.161.

(c) The competent authority of the Member State of registry shall perform sufficient investigation activities for an applicant for, or a holder of, a noise certificate or a restricted noise certificate to justify the issuance, maintenance, amendment, suspension or revocation of the certificate.

IR · 21L.B.171 — Regulation (EU) No 748/2012 · Regulation (EU) 2022/1361 · Initial Airworthiness Easy Access Rules · EAR revision 27 Nov 2025

GM Guidance material

## GM1 21L.B.171(c) Investigation

INVESTIGATION

In the case that the applicant for a noise certificate or a restricted noise certificate issues an EASA Form 52 or an EASA Form 52B under the privileges granted as an approved production organisation under point 21.A.163(b) of Annex I ([Part 21](https://avioverse.aero/glossary/easa/part-21)) to Regulation (EU) No 748/2012, then no further action (i.e. no further showing) during the investigation of the aircraft is required before issuing the relevant certificate.

GM · GM1 21L.B.171(c) — Regulation (EU) No 748/2012 · ED Decision 2023/013/R · Initial Airworthiness Easy Access Rules · EAR revision 27 Nov 2025

[All rules in SECTION B - PROCEDURES FOR COMPETENT AUTHORITIES](https://avioverse.aero/regulations/easa/initial-airworthiness/annex-ib/section-b-procedures-for-competent-authorities)

Consolidated from the EASA Easy Access Rules (revision 27 Nov 2025, extracted 13 Oct 2026) for convenience. Not the official publication — verify against the Official Journal of the European Union and the EASA publications before operational use.