March 25, 2024


Sofema Aviation Services (SAS) reviews the Part M & Part 145 regulatory requirements related to the functioning of the Aircraft Technical Library.

Introduction – Applicable Maintenance Data

Applicable Maintenance data is:

  • Any applicable requirement, procedure, standard, or information issued by the competent authority or the Agency,
  • Any applicable airworthiness directive,
  • Applicable instructions for continuing airworthiness, issued by type certificate holders (TCH), Supplementary type certificate holders (STCH).
  • Other data by Annex I (Part-21) to Regulation (EU) No 748/2012.
  • Any applicable data issued by point 145.A.45(d).

Availability of Technical Data

The organization shall ensure that all applicable maintenance data is current and readily available for use when required including:

  • All applicable maintenance requirements;
  • All applicable ADs;
  • The appropriate sections of the

o Aircraft maintenance programme,

o Aircraft maintenance manual,

o Repair manual,

o Supplementary structural inspection document,

o Corrosion control document,

o Service bulletins,

o Service sheets modification leaflets,

o Non-destructive inspection manual,

o Parts catalogue,

o Type certificate data sheets,

o Vendor maintenance and repair manual, service bulletins, and service letters,

o Any document issued by the type certificate holder as maintenance data.

Note: In the case of operator or customer-provided maintenance data it is not necessary to hold such provided data when the work order is completed.

Engine / APU Maintenance Supporting Data

Applicable maintenance data typically includes

  • Engine maintenance and/or overhaul manual
  • Airworthiness limitations related to Engines if applicable
  • Eng. Wiring diagrams
  • Eng. Parts catalogue
  • Eng. Troubleshooting manual (TSM)

o Issued by the engine TCH (or aircraft TCH if the engine is certified as part of the aircraft) or by

o The DAH.

  • APU maintenance and/or overhaul manual
  • APU wiring diagrams
  • APU parts catalogue
  • APU TSM troubleshooting

o Issued by the aircraft TCH, or

o Issued by the APU manufacturer and acceptable to the TCH of the aircraft on which it is installed or to the DAH.

145.A.45 Maintenance data Requirement’s Ref  (EU) No 1321/2014 & (EU) 2021/700

The organisation shall hold and use applicable current maintenance data in the performance of maintenance, including modifications and repairs.

  • ‘Applicable’ means relevant to any aircraft, component or process specified in the organisation’s approval class rating schedule and in any associated capability list.
  • In the case of maintenance data provided by an operator or customer, the organisation shall hold such data when the work is in progress, with the exception of the need to comply with point 145.A.55(c).

Applicable maintenance data shall be any of the following:

  • Any requirement, procedure, operational directive or information issued by the authority responsible for the oversight of the aircraft or component;
  • Any AD;
  • Instructions for continuing airworthiness (ICAW), issued byData I.A.W Annex I:

o Type certificate holders,

o Supplementary type certificate holders,

o Data I.A.W Annex I (Part-21) to Regulation (EU) No 748/2012,

o (In the case of aircraft or components from third countries the airworthiness data mandated by the authority responsible for the oversight of the aircraft or component).

  • Any applicable standard, such as but not limited to, maintenance standard practices recognised by the Agency as a good standard for maintenance;

Note 1: The organisation shall establish procedures to ensure that if found, any inaccurate, incomplete, or ambiguous procedure, practice, information, or maintenance instruction contained in the maintenance data used by maintenance personnel is recorded and notified to the author of the maintenance data.

Note 2: The organisation may only modify maintenance instructions in accordance with a procedure specified in the maintenance organisation’s exposition.

  • Shall demonstrate result in equivalent or improved maintenance standards and shall inform the type-certificate holder of such changes. (exclude the engineering design of repairs and modifications.)

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Next Steps

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Aircraft Airworthiness, Aircraft Maintenance, Aircraft Repair, Aircraft Technical Library, AMO, Applicable Maintenance Data, Aviation Regulatory Requirements, CAMO, Corrosion control, EASA, EASA CAMO, EASA Type Certificate, Engine maintenance, Instructions for continuing airworthiness (ICAW), Maintenance Data, Part 145, part M, SAS blogs, Technical Data, Technical Library, Troubleshooting manual (TSM), Type certificate holders