EASA SIB 2019-01R1
GPS Week Rollover
Summary
EASA Safety Information Bulletin 2019-01R1 is a revised safety information bulletin addressing the GPS Week Rollover issue affecting aviation navigation and timing systems that rely on GPS receivers. It highlights the potential impact on onboard systems such as Global Navigation Satellite Systems receivers, Flight Management Systems, and Air Traffic Management Systems, without specifying particular aircraft or engine models. The bulletin aims to raise awareness among pilots, air operators, and air navigation service providers about the GPS week counter reset occurring on 6 April 2019.
What Changed
EASA SIB 2019-01R1 revises the original SIB 2019-01 issued on 11 February 2019 by correcting the reference to Commission Regulation (EU) 1034/2011. It updates information regarding the GPS week rollover event and clarifies the timing of the rollover in relation to GPS and UTC time.
Why It Matters
This bulletin is important because the GPS week rollover can cause navigation and timing errors in critical aviation systems, potentially affecting flight safety and air traffic management. Operators and maintenance teams need to be aware of the rollover to prevent system failures or incorrect data interpretation that could disrupt operations or compromise situational awareness.
What To Do
EASA recommends that stakeholders ensure GPS receivers have the latest software updates installed and verify with manufacturers the robustness of their equipment against the GPS week rollover. Operators should conduct tests simulating the rollover event if possible and assume potential failures if the GPS receiver's resilience cannot be confirmed, implementing appropriate mitigation measures accordingly. No mandatory compliance deadlines are specified.