Maintenance Directive NL-2011-001 One-time variations to maintenance intervals

This maintenance directive is published by the CAA-NL, acting as Competent Authority designated by The Netherlands for continuing airworthiness.

Type Approval Holder’s Name



Supersedes OAL 1990-42/4 dated 30 June 1999


One-time variations to maintenance intervals


All Dutch registered aircraft with an EASA CofA

TCDS number



Previously CAA-NL issued OAL 1990-42, based upon Regeling Onderhoud Luchtvaartuigen (ROL) Art. 6, which regulated one-time variations to maintenance intervals, also called extensions, for aircraft not operated in commercial air transport. For commercial air transport, the operator had to define a policy, acceptable to the authorities. JAA A&GM section 2 Maintenance, Part 3, Temporary Guidance Leaflet 26 provided a standard for applying extensions.

With the introduction of Part M for the general aviation, the ROL has been amended to exclude the aircraft regulated under the EASA system.

In the EASA system, there are no regulations for extensions, other than that the design approval holders instructions for continuing airworthiness need to be complied with.

This directive is issued in order to:

  1. provide criteria for extensions, including Commercial Air Transport operations;

  2. improve alignment of the Dutch requirements for extensions with Part-21;

  3. provide criteria for an accepted procedure as referred to in AMC M.A.301-3.

Reason for revision: This MD has been changed to identify that this MD is not mandatory but may be used by an operator as acceptable means of compliance. This MD is issued by the CAA-NL to provide flexibility to operators for the accomplishment of maintenance, in accordance with the M.A.302 approved aircraft maintenance programme, in the absence of recommendations by the design approval holder.

Effective date

14 February 2011
  • One-time variations to maintenance intervals should only be granted when complying with the requirements as published in Appendix A of this MD.

NOTE 1: until amendment of Aircraft Maintenance Programme and/or Continuing Airworthiness Management Exposition as applicable, the procedures contained therein may be applied.

  • As of 01 May 2012 all Aircraft Maintenance Programmes and all Continuing Airworthiness Management Expositions should comply with this MD.

NOTE 2: Application of this MD in the development, revision and application of Aircraft Maintenance Programmes and Continuing Airworthiness Management Expositions is allowed from the effective date.

Appendix A Limitations to one-time variations to maintenance intervals
Appendix B Acceptable Means of  Compliance and Guidance Material