Weather Deviations
General Procedures
Route deviations may be necessary due to weather or other operational constraints. When issuing a route deviation, ATC should provide a direct “when able” point for the aircraft to rejoin its original flight plan. If no point is provided, the aircraft shall remain on its deviation heading and advise ATC when able to return to its cleared route.
ATC should be aware that multiple aircraft may be deviating simultaneously, increasing workload and airspace complexity. Clear and concise communication is critical to ensure proper separation and coordination.
Altitude Deviations
ATC shall monitor aircraft altitude compliance using Mode C altitude readouts. An altitude deviation within 200 feet of the assigned altitude is considered acceptable. If an altitude deviation of 300 feet or more is observed, ATC must intervene.
Weather Deviation Requests
If a pilot requests a weather deviation, ATC shall prioritize response when the pilot states “WEATHER DEVIATION REQUIRED” on frequency. This phrase indicates that priority handling is requested.
Urgency Upgrade
- If the situation escalates, the pilot may upgrade the request to an urgency status.
- ATC shall assess the situation and respond accordingly to ensure flight safety.
Completion of Deviation
- The pilot must notify ATC when:
- Weather deviation is no longer required.
- The aircraft has rejoined its cleared route.
ATC Response Actions
Upon receiving a weather deviation request, ATC shall take one of the following actions:
If Separation Can Be Maintained:
- Issue a clearance for the aircraft to deviate from its assigned track.
If There is Conflicting Traffic and Separation Cannot Be Assured:
- Deny the requested deviation and advise the pilot.
- Inform the pilot of conflicting traffic.
- Request the pilot’s intentions to determine the best course of action.
ATC shall continue to monitor the situation and ensure the aircraft receives further instructions as necessary to maintain separation and operational efficiency.