A number of air navigation service providers (ANSPs) have called attention to instances of pilots’ apparently not understanding the procedures for deviating around weather, prompting Eurocontrol to remind flight crew that they must seek approval from controllers before returning to their previously assigned route once they have resolved the weather conflict. The agency issued an updated version of that safety reminder early this month to explain to crews that they must also request permission to deviate around weather before they begin maneuvering.

In non-oceanic airspace, a crew’s returning to a previously assigned route without communications when clear of the weather makes the controller’s job more difficult and may lead to potential conflicts with other aircraft.

Eurocontrol’s safety reminder focuses on ICAO’s Pans-ATM 8.6.9, Information Regarding Adverse Weather. ICAO documents its expectation that in most cases pilots will have the time to request permission for weather deviations before initiating any turns. There is one exception to the ICAO rule: “In oceanic airspace only, depending on the circumstances, it may be permissible for pilots to return to the previously assigned route without prior notification to ATC.”