Adequate margins (Take-Off - aeroplanes) NCC.POL.125

Axel Wegener • 15 February 2024
in community Air Operations

Need some urgent clarification. NCC.POL.125 (b)(2) when talking about OEI Take-off, the net flight path has to clear the screen height and all obstacles until the 3rd segment (which is the acceleration altitude) by 35ft - right? What is meant with adequate margin related to the (NCC) rule and could it be 0ft? 

GM2 talks about 'Attachment C of ICAO Annex 6, Part I' for an illustrated example. Unable to find in the www ...or elsewhere. Would appreciate any help/hints.

Btw. Annex 6 is about Commercial Aviation...

Comments (5)

Benjamin Hari

Hi Axel,

NCC.POL.125 (b)(2) refers to regulations regarding the performance requirements for aircraft, specifically in the context of non-commercial operations with complex motor-powered aircraft (NCC) under EASA (European Union Aviation Safety Agency) regulations. When discussing One Engine Inoperative (OEI) take-off scenarios, the regulation indeed requires that the net flight path must clear all obstacles by a certain height up to a specific segment of the flight.

For the OEI take-off scenario, the regulation specifies that the net flight path must clear the screen height and all obstacles until the third segment (which is generally defined as the acceleration segment) by 35 feet. This requirement ensures that, in the event of an engine failure, the aircraft can safely continue its climb and clear any obstacles in its flight path with a minimum safety margin.

The term "adequate margin" in the context of aviation safety typically refers to the additional safety buffer beyond the minimum regulatory requirements to account for various uncertainties or operational variations. However, when a regulation specifies a certain clearance height (like the 35 feet mentioned), that specified height becomes the minimum required safety margin. In this context, having an "adequate margin" would mean meeting or exceeding this minimum requirement. It would not be acceptable to have a 0-foot margin over obstacles because the regulation explicitly requires a 35-foot clearance.

Regarding GM2 and the reference to "Attachment C of ICAO Annex 6, Part I", this would be detailed guidance material provided to help understand and apply the regulations. Annex 6 of the ICAO (International Civil Aviation Organization) standards relates to the operation of aircraft and, in Part I, specifically to international commercial air transport operations with aeroplanes. Even though Annex 6 primarily addresses commercial aviation, its standards and recommended practices (SARPs) often serve as reference points for developing regulations and guidance material across various aviation sectors, including non-commercial operations.

Finding specific attachments or guidance material like "Attachment C" can sometimes be challenging due to the way these documents are distributed and accessed. Usually, these documents are available through official channels such as the ICAO's document store or through national aviation authorities and regulatory bodies like EASA. If you are unable to find the document on the web, contacting these organisations directly or accessing their digital libraries and document stores might provide the information you need.


Axel Wegener

Understood so far. By reading the documents again it becomes more clear that CAT.POL.A.210 defines a margin of 35ft (min), whereas for NCC.POL.125 it is only given the 'adequate margin', so not to interpret as an 'add' to the 35ft (from CAT), but being the 'absolute' obstacle clearing distance. With that in mind, it should never and could never be Zero (0) ft!
Maybe the GM2 NCC.POL.125 should make that point more obvious.

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