Subchapter 9.5 – Weather Deviations and Route Changes

Inform ATC as soon as you detect weather ahead that you cannot avoid. Give him time to find a solution.

Example: "Zurich Approach, HB-CDA, heavy precipitation at Flight Level 100, unable to proceed on current routing, request 20-degree left deviation to avoid."

ATC will respond: "HB-CDA, approved, turn left heading 310, continue on current routing after weather."

You execute the turn and report back when weather is clear: "Zurich Approach, HB-CDA, weather clear, resuming cleared route."