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NPA 2016-18

Prediction of wind shear for aeroplanes performing commercial air transport operations

This Notice of Proposed Amendment (NPA) addresses a safety issue related to the effects of wind shear on commercial air transport (CAT) aeroplanes. Wind shear is defined as a sudden change of wind velocity and/or direction. BEA, the French Bureau of Investigation and Analysis for Civil Aviation Safety, issued Safety Recommendation (SR) FRAN-2009-0121 for a regulation to be introduced on the installation of predictive wind shear systems (PWSs) in accordance with ICAO recommendations contained in its Annex 6 Part I ‘Operation of Aircraft — International Commercial Air Transport — Aeroplanes’.

The objective of this NPA is to mitigate the risks linked to the effect of wind shear during a take-off from, approach to and landing at an airport.

Although large aeroplanes having a maximum certified take-off mass (MCTOM) of more than 60 tonnes manufactured today are generally equipped with PWSs, there are many aeroplanes in service which either only have reactive wind shear systems (RWSs) or no wind shear warning systems at all. RWSs only trigger a warning once wind shear has been encountered, thus preventing the flight crew from anticipating such an event. PWSs, however, provide alerts to the flight crew prior to encountering wind shear events, thus enabling better management of the safety risk related to it.

This NPA does not contain a regulatory proposal. Based on the assessment performed by EASA, the conclusion is that no regulatory action is needed to require RWSs and/or PWSs for European-registered aircraft. The NPA provides an answer to SR FRAN-2009-012 addressed to EASA as regards equipping aeroplanes with PWSs and RWSs.

The proposed way forward is expected to maintain the current level of safety.