COMMISSION REGULATION (EU) No 1332/2011  
of 16 December 2011  
laying down common airspace usage requirements and operating procedures for airborne collision 
avoidance  
(Text with EEA relevance)  
THE EUROPEAN COMMISSION,  
Having regard to the Treaty on the Functioning of the European 
Union,  
Having regard to Regulation (EC) No 216/2008 of the European 
Parliament and of the Council of 20 February 2008 on 
common rules in the field of civil aviation and establishing a 
European Aviation Safety Agency, and repealing Council 
Directive 91/670/EEC, Regulation (EC) No 1592/2002 and 
Directive 2004/36/EC (  1 ), and in particular Articles 8(1), 8(5), 
and 9(4) thereof,  
Whereas:  
(1) Safety requirements should be imposed on operators of 
aircraft registered in a Member State or registered in a 
third country and operated by a Union operator, and on 
operators of aircraft used by a third country operator 
within the Union.  
(2) Following a series of mid-air encounters in which safety 
margins have been lost, including accidents in Yaizu 
(Japan) in 2001 and in Überlingen (Germany) in 2002, 
the current airborne collision avoidance system software 
should be upgraded. The studies concluded that with the 
current airborne collision avoidance system software 
there is a probability of a mid-air collision risk of 
2,7 × 10  –8 per flight hour. Therefore the current ACAS 
II version 7.0 is considered to be of an unacceptable 
safety risk.  
(3) It is necessary to introduce a new software version of the 
airborne collision avoidance system (ACAS II) to avoid 
mid-air collision of all aircraft flying in the airspace 
covered by Regulation (EC) No 216/2008.  
(4) To ensure the highest possible safety standards, aircraft 
which do not fall within the scope of the mandatory 
carriage requirement but were equipped with ACAS II 
prior to entry into force of this Regulation should 
install ACAS II containing the latest version of collision 
avoidance software.  
(5) In order to ensure that the safety benefits associated with 
the new software version are achieved, all aircraft need to 
be equipped as soon as practically possible. However, it is necessary to provide a realistic time for the aeronautical 
industry to adapt to this new Regulation taking into 
account the availability of new equipment.  
(6) The Agency prepared draft implementing rules and 
submitted them as an opinion to the Commission in 
accordance with Article 19(1) of Regulation (EC) No 
216/2008.  
(7) The measures provided for in this Regulation are in 
accordance with the opinion of the European Aviation 
Safety Agency Committee established by Article 65 of 
Regulation (EC) No 216/2008,  
HAS ADOPTED THIS REGULATION:  
Article 1  
Subject matter and scope  
This Regulation lays down common airspace usage 
requirements and operating procedures for airborne collision 
avoidance to be fulfilled by:  
(a) operators of aircraft referred to under Article 4(1)(b) and (c) 
of Regulation (EC) No 216/2008 undertaking flights into, 
within or out of the Union; and  
(b) operators of aircraft referred to under Article 4(1)(d) of 
Regulation (EC) No 216/2008 undertaking flights within 
the airspace above the territory to which the Treaty 
applies as well as in any other airspace where Member 
States apply Regulation (EC) No 551/2004 of the 
European Parliament and of the Council (  2 ). 
Article 2  
Definitions  
For the purposes of this Regulation the following definitions 
shall apply:  
(1) ‘airborne collision avoidance system (ACAS)’ means an 
aircraft system based on secondary surveillance radar 
(SSR) transponder signals which operates independently of 
ground-based equipment to provide advice to the pilot on 
potential conflicting aircraft that are equipped with SSR 
transponders;EN L 336/20 Official Journal of the European Union 20.12.2011  
( 1 ) OJ L 79, 19.3.2008, p. 1.  (  2 ) OJ L 96, 31.3.2004, p. 20.(2) ‘airborne collision avoidance system II (ACAS II)’ means an 
airborne collision avoidance system which provides vertical 
resolution advisories in addition to traffic advisories;  
(3) ‘resolution advisory (RA) indication’ means an indication 
given to the flight crew recommending a manoeuvre 
intended to provide separation from all threats or a 
manoeuvre restriction intended to maintain existing 
separation;  
(4) ‘traffic advisory (TA) indication’ means an indication given 
to the flight crew that the proximity of another aircraft is a 
potential threat.  
Article 3  
Airborne collision avoidance system (ACAS)  
1. The aeroplanes referred to in Section I of the Annex to 
this Regulation shall be equipped with and operated in 
accordance with the rules and procedures as specified in the 
Annex.  
2. Member States shall ensure that operation of aeroplanes 
referred to in Article 1(2)(a) of Regulation (EC) No 216/2008 
comply with the rules and procedures specified in the Annex in 
accordance with the conditions set out in that Article.  Article 4  
Special provisions applying to operators subject to Council 
Regulation (EEC) No 3922/91  ( 1 ) 
1. By derogation from provisions OPS 1.668 and OPS 1.398 
of Annex III to Regulation (EEC) No 3922/91, Article 3 and the 
Annex to this Regulation shall apply for operators of aeroplanes 
referred to in Article 1(a).  
2. Any other obligation imposed on air operators by Regu ­
lation (EEC) No 3922/91 as regards the approval, installation or 
operation of equipment shall continue to apply to ACAS II.  
Article 5  
Entry into force and application  
1. This Regulation shall enter into force on the 20th day 
following its publication in the  Official Journal of the European 
Union . 
2. Articles 3 and 4 shall apply as of 1 March 2012.  
3. By way of derogation from paragraph 2, in the case of 
aircraft with an individual certificate of airworthiness issued 
before 1 March 2012, the provisions of Article 3 and 4 shall 
apply as of 1 December 2015.  
This Regulation shall be binding in its entirety and directly applicable in all Member States.  
Done at Brussels, 16 December 2011.  
For the Commission  
The President  
José Manuel BARROSOEN 20.12.2011 Official Journal of the European Union L 336/21  
( 1 ) OJ L 373, 31.12.1991, p. 4.ANNEX  
Airborne collision avoidance systems (ACAS) II  
(Part-ACAS)  
Section I  — ACAS II equipment  
AUR.ACAS.1005  Performance requirement  
(1) The following turbine-powered aeroplanes shall be equipped with collision avoidance logic version 7.1 of ACAS II:  
(a) aeroplanes with a maximum certificated take-off mass exceeding 5 700 kg; or  
(b) aeroplanes authorised to carry more than 19 passengers.  
(2) Aircraft not referred to in point (1) but which will be equipped on a voluntary basis with ACAS II, shall have collision 
avoidance logic version 7.1.  
(3) Point (1) shall not apply to unmanned aircraft systems.  
Section II  — Operations  
AUR.ACAS.2005  Use of ACAS II  
(1) ACAS II shall be used during flight, except as provided in the minimum equipment list as specified in Annex III to 
Regulation (EEC) No 3922/91, in a mode that enables RA indications to be produced for the flight crew when undue 
proximity to another aircraft is detected, unless inhibition of RA indication mode (using TA indication only or 
equivalent) is called for by an abnormal procedure or due to performance limiting conditions.  
(2) When an RA indication is produced by ACAS II:  
(a) the pilot flying shall immediately conform to the indications of the RA indication, even if this conflicts with an air 
traffic control (ATC) instruction, unless doing so would jeopardise the safety of the aircraft;  
(b) the flight crew, as soon as permitted by workload, shall notify the appropriate ATC unit of any RA which requires 
a deviation from the current ATC instruction or clearance;  
(c) when the conflict is resolved, the aircraft shall:  
(i) be promptly returned to the terms of the acknowledged ATC instruction or clearance and ATC notified of the 
manoeuvre; or  
(ii) comply with any amended ATC clearance or instruction issued.  
AUR.ACAS.2010  ACAS II training  
Operators shall establish ACAS II operational procedures and training programmes so that the flight crew is appropriately 
trained in the avoidance of collisions and competent in the use of ACAS II equipment.EN L 336/22 Official Journal of the European Union 20.12.2011