---
title: "21L.B.173 Oversight — Annex Ib, Initial Airworthiness · Avioverse"
description: "Upon evidence of a violation of any of the conditions under which the noise certificate or the restricted noise certificate was issued, or that the…"
url: "https://avioverse.aero/regulations/easa/initial-airworthiness/annex-ib/section-b-procedures-for-competent-authorities/21l-b-173"
---

# 21L.B.173 Oversight

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

IR Implementing rule

## 21L.B.173 Oversight

(a) Upon evidence of a violation of any of the conditions under which the noise certificate or the restricted noise certificate was issued, or that the holder does not comply with the relevant requirements of Regulation (EU) 2018/1139 and the delegated and implementing acts adopted on the basis thereof or with the applicable type design or with the applicable design data of an aircraft for which design compliance has been declared, the competent authority of the Member State of registry shall issue a finding in accordance with point 21L.B.21.

(b) When the type certificate under which the noise certificate was issued is suspended or revoked, or otherwise becomes invalid in accordance with point 21L.A.30, or the declaration of design compliance under which the restricted noise certificate was issued is not any longer registered in accordance with point 21L.B.63, the competent authority of the Member State of registry shall take action in accordance with point 21L.B.22.

IR · 21L.B.173 — Regulation (EU) No 748/2012 · Regulation (EU) 2022/1361 · 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.