out in article 21. The Emissions Monitoring Plan must contain the information specified in  Schedule 4.  24. —(1) If an aeroplane operator submits an Emissions Monitoring Plan for approval by the  Regulator in accordance with article 23, a Regulator must approve and issue the Emissions  Monitoring Plan unless—  (2) An Emissions Monitoring Plan issued under paragraph (1) replaces any Emissions  Monitoring Plan previously issued to the aeroplane operator.  (3) An Emissions monitoring Plan may contain any conditions the Regulator considers  necessary to give proper effect to the requirements of this Order.  (4) An aeroplane operator must comply with any condition included in its Emissions Monitoring  Plan.  25. —(1) If a Regulator refuses an application for an Emissions Monitoring Plan, the Regulator  must give notice to the applicant.  (2) A notice under paragraph (1) must state—  (3) An aeroplane operator who is given a notice under paragraph (1) must make a revised  application to the Regulator before the end of the period of 31 days beginning with the day that the  notice was given.  (4) Article 24 and this article apply to a revised application under paragraph (3) as they apply to  the original application, but for the purposes of such a revised application, the references to the  period of 2 months in article 19 are to be read as references to a period of 24 days.  26. —(1) An aeroplane operator must notify the Regulator of any proposals for modification of  its Emissions Monitoring Plan.  (2) The aeroplane operator must resubmit the Emissions Monitoring Plan to the Regulator for  approval if a material change is made to the information contained within the Emissions  Monitoring Plan.  (3) A material change is a change to the information presented in the Emissions Monitoring Plan  that would—  (4) The aeroplane operator must also resubmit the Emissions Monitoring Plan in the event of a  change to the information presented in the plan that—  16 (a) arises from a change in the availability of data, due to the use of new types of measuring  instrument, sampling methods or analysis methods, or for other reasons, which leads to  higher accuracy in the determination of emissions,  (b) otherwise affect the decision by the Regulator with regard to whether the aeroplane  operator’s approach to monitoring conforms with the requirements.  (a) affect the status or eligibility of the aeroplane operator for an option under the emissions  monitoring requirements, or  Modification of the Emissions Monitoring Plan  (b) if amendments of the application are required in order for an Emissions Monitoring Plan  to be issued, the nature of those amendments.  (a) the reasons for the decision; and  (b) the aeroplane operator has not agreed to amendments of the application required to satisfy  the Regulator that the application does so comply.  (a) the Regulator is not satisfied that the application complies with the requirements of this  Order; and  Issue of Emissions Monitoring Plans  Refusal of application for Emissions Monitoring Plans 