91.—(1) Subject to paragraph (4), this article applies to a flight for the purpose of the public transport of passengers by an aircraft registered in the United Kingdom.
(2) The commander of a flight to which this article applies in an aircraft for which a certificate of airworthiness was first issued (whether in the United Kingdom or elsewhere) on or after 1st January 1989 must take all reasonable steps to ensure that each of the actions described in column 1 of the following table is carried out.
(3) The commander of a flight to which this article applies in an aircraft for which a certificate of airworthiness was first issued (whether in the United Kingdom or elsewhere) before 1st January 1989 must take all reasonable steps to ensure that each of the actions described in either column 1 or in column 2 of the following table is carried out.
| Column 1 | Column 2 |
|---|---|
| Before the aircraft reaches flight level 100 the method of use of the oxygen provided in the aircraft in compliance with the requirements of article 37 and Schedule 4 is demonstrated to all passengers | Before the aircraft reaches flight level 130 the method of use of the oxygen provided in the aircraft in compliance with the requirements of article 37 and Schedule 4 is demonstrated to all passengers |
| When flying above flight level 120 all passengers and cabin crew are recommended to use oxygen | When flying above flight level 130 all passengers and cabin crew are recommended to use oxygen |
| During any period when the aircraft is flying above flight level 100 oxygen is used by all the flight crew of the aircraft | During any period when the aircraft is flying above flight level 100 oxygen is used by all the flight crew of the aircraft. |
(4) This article does not apply—
(a)to a flight under and in accordance with the terms of a police air operator’s certificate; or
(b)in a case where a pressure greater than 700 hectopascals is maintained in all passenger and crew compartments throughout the flight.