Inflight Weather Advisory Broadcasts

AIM ¶ 7-1-8 — Inflight Weather Advisory Broadcasts

AIM 7-1-8 explains how ARTCCs broadcast SIGMETs, AIRMETs, CWAs, and Urgent PIREPs to alert pilots of hazardous weather within 150 miles.

In Plain English

AIM 7-1-8 describes how ARTCCs (Air Route Traffic Control Centers) alert pilots to hazardous weather while you're flying. When any part of a hazardous weather area falls within 150 miles of the airspace they control, ARTCCs broadcast an alert once on all frequencies (except emergency frequencies).

These broadcasts are alerts only — they tell you that a hazardous weather advisory exists and direct you to contact the nearest Flight Service facility for the full details. Advisories that trigger these broadcasts include:

Convective SIGMET (thunderstorms, hail, tornadoes)
SIGMET (severe icing, severe turbulence, volcanic ash, dust/sandstorms)
AIRMET (except in the contiguous U.S.)
Urgent PIREP
CWA (Center Weather Advisory)

Terminal facilities (tower cab and approach control) have the option to limit broadcasts to weather within 50 miles of their airspace.

Why it matters: as PIC, you're responsible for avoiding hazardous weather. When you hear an ARTCC alert, switch over to Flight Service to get specifics so you can make a sound diversion or altitude-change decision.

AIM Source Text

FAA AIM ¶ 7-1-8

7-1-8. 7-1-8. Inflight Weather Advisory Broadcasts ARTCCs broadcast a Convective SIGMET, SIGMET, AIRMET (except in the contiguous U.S.), Urgent Pilot Report, or CWA alert once on all frequencies, except emergency frequencies, when any part of the area described is within 150 miles of the airspace under their jurisdiction. These broadcasts advise pilots of the availability of hazardous weather advisories and to contact the nearest flight service facility for additional details. EXAMPLE- 1. Attention all aircraft, SIGMET Delta Three, from Myton to Tuba City to Milford, severe turbulence and severe clear icing below one zero thousand feet. Expected to continue beyond zero three zero zero zulu. Attention all aircraft, convective SIGMET Two Seven Eastern. From the vicinity of Elmira to Phillipsburg. Scattered embedded thunderstorms moving east at one zero knots. A few intense level five cells, maximum tops four five zero. Attention all aircraft, Kansas City Center weather advisory one zero three. Numerous reports of moderate to severe icing from eight to niner thousand feet in a three zero mile radius of St. Louis. Light or negative icing reported from four thousand to one two thousand feet remainder of Kansas City Center area. NOTE- Terminal control facilities have the option to limit hazardous weather information broadcast as follows: Tower cab and approach control positions may opt to broadcast hazardous weather information alerts only when any part of the area described is within 50 miles of the airspace under their jurisdiction. REFERENCE- FAA Order JO 7110.65, Para 2-6-6, Hazardous Inflight Weather Advisory.

Oral Exam Questions a DPE Might Ask

Q1When does an ARTCC broadcast a hazardous weather advisory alert?

Per AIM 7-1-8, ARTCCs broadcast the alert once on all frequencies except emergency frequencies when any part of the described area is within 150 miles of the airspace under their jurisdiction.

Q2What types of weather advisories trigger these inflight broadcasts?

Per AIM 7-1-8, the broadcasts cover Convective SIGMETs, SIGMETs, AIRMETs (except in the contiguous U.S.), Urgent Pilot Reports, and Center Weather Advisories (CWAs).

Q3After hearing an ARTCC hazardous weather alert, what should you do to get the details?

Per AIM 7-1-8, the broadcast only advises that an advisory exists; pilots should contact the nearest Flight Service facility for additional details.

Related Paragraphs in AIM Chapter 7

¶ 7-1-1

NWS Aviation Weather Program

¶ 7-1-10

Weather Observing Programs

¶ 7-1-11

Weather Radar Services

¶ 7-1-12

ATC Weather Avoidance

¶ 7-1-13