Contact

Aeronautical Information Management Department
222 Soi Vibhavadi Rangsit 28,
Vibhavadi Rangsit Rd., Chatuchak,
Chatuchak, Bangkok 10900 Thailand

Tel: +662 568 8831

Fax: +662 576 1903

AFS: VTBAYOYX

Email: [email protected]

AIC for Thailand

AIC

05/25

Effective from 04 SEP 2025

to UFN

Published on 24 JUL 2025

INCREASED GLOBAL NAVIGATION SATELLITE SYSTEM
(GNSS) INTERFERENCE ENCOUNTERS

1 INTRODUCTION

Disruptions towards the performance of Global Navigation Satellite System (GNSS) equipment and related avionics have been increasingly encountered within the Bangkok FIR due to GNSS Radio Frequency Interference (RFI), with most encounters from flights inbound and outbound from the western direction (Yangon FIR).

2 DESCRIPTION

2.1 For flights entering/leaving Bangkok FIR from the west, flight crews are advised to verify aircraft position by means of conventional navigation aids and remain prepared to revert to conventional procedures where appropriate.

2.2 Flight crews are encouraged to promptly report via special air-report (AIREP) to air traffic control any observed interruption, degradation or anomalous performance of GNSS equipment or related avionics (eg., map shifts, suspected GNSS spoofing, lost or misleading position, time anomalies, etc., including their duration).

2.3 Flight crews are encouraged to report GNSS RFI occurrences through Thailand's Aviation Safety Occurrence Reporting Portal which can be accessed at https://portal.caat.or.th/occurrence .

3 VALIDITY