Meteorological information is mandated for safe, regular, efficient civil aviation, not optional guidance, anchoring legal obligations across international and domestic systems. ICAO Annex 3 sets the objective and core standards for providing forecasts, warnings, and observations tailored to aviation hazards and distribution to operators, flight crew, ATS units, and SAR services. States implement Annex 3 via designated meteorological authorities and register differences; the Bureau of Meteorology example shows compliance responsibilities and alignment of domestic SARPs to Annex.
Core regulatory sources
- ICAO Annex 3: scope, required products, formats, and supply mechanisms for aviation meteorology, including SIGMETs, AIRMETs, and hazard reporting standards.
- WMO aviation page: confirms meteorology’s critical role and its alignment with international safety and efficiency objectives.
- FAA framework: 14 CFR Part 91 requires pilots to obtain all available information preflight; there is no such thing as a “legal weather briefing”, only compliance with §91.103 and AC 91-92 guidance for self-briefings.
Who must do what
- Pilots: under §91.103, must obtain all available information, including weather, NOTAMs, and runway data; records of briefings support showing compliance but are not a separate legal category.
- Operators (Part 121/135): must use approved sources for weather reports and forecasts at departure, destination, and alternates; weather program approval and source control are required.
- ATC/ATS units: must disseminate relevant weather hazards to aircraft and coordinate hazard information per Annex 3 and ATS procedures, including SIGMET/volcanic ash dissemination.
Weather hazards that trigger duties
Annex 3 requires tailored products covering turbulence, icing, wind shear, volcanic ash, tropical cyclones, and other aviation-specific phenomena with defined formats and dissemination channels. WAFS provides global gridded forecasts that underpin flight-level wind/temperature/turbulence/icing guidance and set expectations for what operators can reasonably access and act on. WMO and state authorities emphasize hazard-focused, efficiency-oriented products to meet safety and regularity objectives in daily operations.
Liability: when weather becomes fault
Weather can be an external hazard, but liability turns on use, interpretation, and communication of available information within governing standards. Pilot negligence risk increases when proceeding despite forecasted hazards that a reasonable pilot should have heeded under §91.103 and AC 91-92 preflight and inflight updates. Operator liability arises when failing to use approved sources or distribute updated advisories to crews per Part 121/135 weather program requirements and Ops Specs. ATS liability risk relates to failures in required dissemination of significant meteorological information within ATS responsibilities tied to Annex 3 interface procedures.
Tech raises the standard of care
Modern tools—high-resolution satellites, radar mosaics, numerical models, and global WAFS grids—improve predictability and availability, which elevates expectations for what information should be integrated into decisions and records. FAA’s 2024 Aviation Weather Handbook consolidates interpretation guidance consistent with contemporary data sources, shaping what counts as reasonable weather analysis for pilots and dispatchers. As states adopt Annex 3 updates and publish differences, regulated parties must track evolving product formats and distribution mechanisms to stay compliant.
FAA: Part 91 vs 121 vs 135 weather
- Part 91: general aviation; pilot-centric duty to obtain all available information under §91.103; no formal “legal briefing”, but AC 91-92 outlines compliant self-briefing processes and documentation practices.
- Part 135: charter/commuter; stricter operational control and weather source approval requirements, including use of approved reports and forecasts for IFR alternates.
- Part 121: scheduled air carriers; dispatch/flight-release systems with mandatory use of approved weather sources and continuous monitoring/updates as part of operational control.
Practical compliance checklist
- Use Annex 3–aligned, state-approved weather products for planning, release, and enroute updates; confirm provider approval status for 121/135.
- Document preflight self-briefing with comprehensive coverage of METARs, TAFs, SIGMET/AIRMET, winds aloft, NOTAM-integrated weather impacts, and risk mitigation per AC 91-92.
- Integrate WAFS gridded products and state hazard advisories into performance, fuel, and route decisions; update when new SIGMETs or ash advisories publish.
- Train ATS and dispatch interfaces on required dissemination and handoff procedures for significant weather to avoid gaps in communication chains.