EASA SIB 2017-14: Terrain Awareness Warning Systems

What to do

Owners and operators of affected turbine-powered aeroplanes should plan to install Class B TAWS that meet acceptable standards such as ETSO-C151b, especially for aircraft with a Certificate of Airworthiness issued after 1 January 2019. They should also ensure that any existing TAWS functions in avionics are not disabled or inhibited and include checks in the aircraft maintenance program to maintain TAWS functionality. While recommendations for retrofitting existing aircraft are voluntary, operators are encouraged to consider installation to improve safety.

Summary

EASA Safety Information Bulletin No. 2017-14 provides guidance on Terrain Awareness Warning Systems (TAWS) for turbine-powered aeroplanes with a maximum certified take-off mass of less than 5,700 kg and seating for six to nine passengers. The bulletin references regulatory opinions and accident reports to highlight the importance of TAWS in reducing controlled flight into terrain (CFIT) accidents. It applies primarily to small commercial turbine-powered aircraft operating under instrument and visual flight rules.

What changed

EASA Opinion 15/2016 proposes a regulatory change requiring turbine-powered aeroplanes with a maximum certified take-off mass of 5,700 kg or less and seating for six to nine passengers, first issued a Certificate of Airworthiness after 1 January 2019, to be equipped with Class B TAWS meeting acceptable standards such as ETSO-C151b. The bulletin also discusses considerations regarding retrofitting TAWS on existing aircraft and extending requirements to non-commercial operations, but these were not mandated due to proportionality concerns.

Why it matters

This bulletin informs operators, manufacturers, and maintenance organizations about upcoming regulatory requirements and safety recommendations aimed at reducing CFIT accidents in small turbine-powered aircraft. Compliance with TAWS installation enhances flight safety and aligns with international ICAO recommendations, impacting operational procedures and maintenance programs. Understanding these changes helps aviation professionals prepare for equipment upgrades and regulatory compliance.