# Commission Implementing Regulation (EU) No 923/2012 of 26 September 2012 laying down the common rules of the air and operational provisions regarding services and procedures in air navigation and amending Implementing Regulation (EU) No 1035/2011 and Regulations (EC) No 1265/2007, (EC) No 1794/2006, (EC) No 730/2006, (EC) No 1033/2006 and (EU) No 255/2010 (Text with EEA relevance), Division SERA.13010: Pressure-altitude-derived information

Extent: E+W+S+N.I.

(a) When the aircraft carries serviceable Mode C equipment, the pilot shall continuously operate this mode unless otherwise dictated by ATC.
(b) Unless otherwise prescribed by the competent authority, verification of the pressure-altitude-derived level information displayed to the controller shall be effected at least once by each suitably equipped ATC unit on initial contact with the aircraft concerned or, if this is not feasible, as soon as possible thereafter.

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Source: https://www.legislation.gov.uk/eur/2012/923/annex/section/13/division/SERA.13010 (the official version)
Page: https://openlegislation.uk/eu-regulation-2012-923/annex/section-13/division-SERA.13010
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.