---
title: "GM34 Annex I Definitions — ANNEX I – Definitions, Air OPS · Avioverse"
description: "DECISION ALTITUDE (DA) OR DECISION HEIGHT (DH) (a) Decision altitude (DA) is referenced to mean sea level and decision height (DH) is referenced to the…"
url: "https://avioverse.aero/regulations/easa/air-ops/definitions/powers-and-recitals/gm34-annex-i-definitions"
---

# GM34 Annex I Definitions

ANNEX I – Definitions · Regulation (EU) No 965/2012 · EAR revision 27 Mar 2026

Official sources: [EASA Easy Access Rules (opens in a new tab)](https://www.easa.europa.eu/en/document-library/easy-access-rules/easy-access-rules-air-operations) · [EUR-Lex 2012/965 (opens in a new tab)](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32012R0965)

GM Guidance material

## GM34 Annex I Definitions

[DECISION ALTITUDE (DA) OR DECISION HEIGHT (DH)](https://avioverse.aero/glossary/easa/decision-altitude-or-decision-height)

(a) Decision altitude (DA) is referenced to mean sea level and decision height (DH) is referenced to the threshold elevation.

(b) For operations using DA, the [aircraft](https://avioverse.aero/glossary/easa/aircraft) altimeters are set to QNH. For operations using a barometric DH, the aircraft altimeters are set to QFE.

(c) For SA CAT I, SA CAT II, CAT II/III operations, the DH is based on the use of a radio altimeter or other devices capable of providing equivalent performance. The DH is determined with reference to threshold elevation, but the value of the DH set for the approach will be based on the height of the aircraft above the pre-threshold terrain, which may be higher or lower than the threshold.

(d) For convenience, when both expressions are used, they may be written in the form ‘decision altitude/height’ and abbreviated ‘DA/H’.

GM — Regulation (EU) No 965/2012 · ED Decision 2022/012/R · Air OPS Easy Access Rules · EAR revision 27 Mar 2026

[All rules in Powers and recitals](https://avioverse.aero/regulations/easa/air-ops/definitions/powers-and-recitals)

Consolidated from the EASA Easy Access Rules (revision 27 Mar 2026, extracted 2 Nov 2026) for convenience. Not the official publication — verify against the Official Journal of the European Union and the EASA publications before operational use.