Understanding Part-NCO MELs and INOP equipment

Florian Rhyn • 19 April 2019

in community General Aviation

1 likes

Dear EASA and GA community

I have never met a pilot, in CAAs even, who truly understood what the implications are of INOP equipment under Part-NCO. A clarification would be greatly appreciated and a clear answer would go a long way.

Legal basis:
- ED Decision 2014/005/R, its annex or, consolidated and simpler, the Easy Access Rules for Generic Master Minimum Equipment Lists CS-GEN-MMEL
- NCO.GEN.155 and AMC2 NCO.GEN.155

NCO.GEN.155 states that, under Part-NCO, we may establish an MEL and shall notify it and all revisions to the authority (e.g. an e-mail with the PDF). This is to be read in contrast to NCC and CAT, where the wording is very similar but the word “approved” is replaced by “notified” in NCO. Consequently, the CAA does not have a legal basis to “approve” an MEL under NCO and that is fine.

The ED Decision’s executive summary states the following:
“[…] Moreover, in accordance with the additional requirements for air operations for commercial purposes laid down in Annex IV to Article 8 of the Basic Regulation, an operator must establish a Minimum Equipment List (MEL) or equivalent document based on the Master Minimum Equipment List (MMEL).
This requirement for commercial operations has been transposed in the Implementing Rules for Air Operations, namely in Part ORO. The possibility of establishing an MEL on a voluntary basis for non-commercial operations of other-than-complex motor-powered aeroplanes has been also foreseen in the Implementing Rules for Air Operations in Part-NCO.
Following these considerations, the Agency introduces with this Decision the CS-GENERIC-MMEL for other-than-complex motor-powered aeroplanes with the aim of assisting the type certificate holder in developing the Master Minimum Equipment List (MMEL)."
Clearly, this CS-GEN-MMEL is a template intended for type certificate holders to establish their MMEL. However, the second paragraph is referencing NCO.GEN.155 and, according to the third paragraph, this use case in NCO was a consideration when developing this CS-GEN-MMEL as a template.

AMC2 NCO.GEN.155 states that the standard format for MELs should be used (according MMEL and IATA 100/2200 Specification numbering system for MEL items) or be clear and unambiguous. So, in many cases NCO aircraft do not have an MEL and the CS-GEN-MMEL might be overkill and I could simply write an A5 paper that states: “Cessna 172, Registration xyz, Serial #12345 / Landing light INOP → Flying at night prohibited” and then I would be legal to fly with an INOP landing light. Of course I couldn’t list anything that is required by type design (oil pressure gauge etc.) or by the equipment rules in NCO.IDE.

Or is it even simpler? NCO.IDE.105 states that you shall not fly when any of the aeroplane equipment required for the intended flight are inoperative or missing, unless: an MEL or permit to fly is available.

In the landing light example for a daytime flight, is this considered equipment not required for the intended flight and therefore does not require an MEL?

The current confusing situation is not helpful in the GA community. Especially compared to the clearer FAA rules (FAR 91.213).

Thank you very much for anyone taking some time to shed light on this subject. :-)

Best regards

Florian

Julian Scarfe • 5 years ago

(I replied in the other place, but I'll also comment here)

You're correct in that NCO.IDE.105 only refers to required equipment, and therefore if equipment is not required for the intended flight, it can be inoperative.

The equipment requirements in Part-NCO are pretty minimal, and so there are few cases in which an MEL can reasonably offer an alleviation and still maintain a sensible level of safety. But there may be a few where the manufacturer has developed specific Operational or Maintenance procedures in their MMEL to mitigate the inoperability of the required equipment, and there are a couple of generic cases in CS-MMEL.

But in general I would say there is little operational advantage in an NCO operator developing an MEL. You might find it useful to avoid having to refer to Part-NCO though.

The ability to use the CS-GEN-MMEL material for those aircraft without an approved MMEL was identified a few years ago by the (now) GA COM, hence GM1 NCO.GEN.155(b) as follows, introduced a couple of years ago:

"If an MMEL established as part of the operational suitability data is not available and items subject to operational requirements are listed in the available MMEL without specific relief or dispatch conditions but only with a reference to the operational requirements, the operator may refer to CS-MMEL or CS-GEN-MMEL guidance material, as applicable, to develop the relevant MEL content for such items."

Note that these equipment requirements are distinct requirements from those (M.A.403 in Part-M, or ML.A.403 in the forthcoming Part-ML) for the deferral of defects, including inoperative equipment, though they are obviously related.

Personally, I find FAR 91.213 rather difficult to follow, though I suppose if you're used to it it makes sense.

Comments (2)

General Aviation