Sofema Aviation Services (SAS) www.sassofia.com considers the role of Operational Suitability Data (OSD) Related to the Master Minimum Equipment List (MMEL).
Introduction – Why do we need an MMEL Certification Basis?
In fact, before the year 2000, there was no standard requirement. Between 2000 & 2014 the standard was managed in accordance with JAR MMEL.
The Role of the MMEL
The MMEL is intended to ensure the maintenance of an acceptable level of safety (As intended in the applicable JAR or Equivalent Requirement) to approve an MMEL compliant with JARs required a degree of subjective acceptability with the authority taking a shared responsibility approach.
Moreover, there was in place a wide variety of TCH MMEL methodologies and no baseline guidance document comparable to FAA MMEL Policy Letters or TCCA guidance book.
CS MMEL Provides necessary requirements/criteria for compliance finding in a Type Certification framework & maintains consistency with the JOEB process with the JAR MMEL content integrated within the document.
CS MMEL Consists of:
- CS MMEL Section 1 Subpart A General
- CS MMEL Section 1 Subpart B MMEL
Regulatory Drivers for the MMEL
ORO.MLR.105 (A) REQUIRES EU OPERATORS TO:
- Base their new MELs on OSD MMEL available directly from the Type Certificate Holder.
- Data has to be made available by (S)TC Holders as per 21.A.62/108/120B.
- Design Approval Holders (DAH) were required to Update their MEL as per OSD MMEL at the earliest opportunity and not later than 18 December 2017 or 2 years after the OSD was approved, whichever is the latest.
Note: The MMELs status will no longer be published on the EASA website. Data has to be made available by (S)TC Holders as per 21.A.62/108/120B.
Operator Requirements for an MEL
Operators Shall have an MEL (ORO.MLR.105) if conducting:
- Commercial air transport operations (CAT);
- Commercial specialized operations;
- Non commercial operations with complex motor powered aircraft;
- Non commercial specialized operations with complex motor powered aircraft.
Optional MEL Requirement
May have an MEL (NCO.GEN.155), if conducting:
- Non commercial operations with non complex motor powered aircraft.
OSD Driven MMEL
With MMEL in OSD we have now:
- Approval process comparable to Type Design Certification
- Clearer sharing of duties and responsibilities between Agency and (S)TC Holders
- A tool (Process) for adapting EASA level of involvement
- Additional privileges for DOA holders for MMEL minor changes approval
MMEL Development Methodology
MoC to CS-MMEL.140
- “an acceptable level of safety as intended by the applicable requirements is maintained”
What is acceptable shall be defined in MoC “performance based requirements” not prescriptive (like CS-25 etc.)
Note – The Methodology is an essential aspect of the OSD MMEL
MMEL Safety Methodology
MoC to CS-MMEL.140/145
- CS MMEL.145 (c)(1) Consequences of the item failure:
Fail/pass criteria to be defined by TCH CS MMEL.145 (c)(2) Consequences of the next worst failure/event:
- Not HAZ or CAT except if supported by quantitative assessment
- Fail/pass criteria to be defined by TCH
- CS MMEL.145 (d) quantitative assessment for items in minimal cut sets 2 to HAZ or 3 to CAT
Next Steps
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Sofema Aviation Services (SAS) www.sassofia.com provides regulatory training for EASA Part 21, CS 25 & OSD – please see the following 1-Day course. For additional details, please visit our websites or email team@sassofia.com
Tags:
Safety, FAA, CAT, JAR, OSD, MEL, MMEL, Type Certificate, Minimum Equipment List (MEL), Operational Suitability Data (OSD), Master Minimum Equipment List (MMEL)
