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149 ms- §7-1-12AIM — FAA OPERATIONAL GUIDANCE
7-1-12 — ATC Inflight Weather Avoidance Assistance
a. ATC Radar Weather Display. 1. ATC radars are able to display areas of precipitation by sending out a beam of radio energy that is reflected back to the radar antenna when it strikes an object or moisture which may be in the form of rain
- §7-1-13AIM — FAA OPERATIONAL GUIDANCE
7-1-13 — Runway Visual Range (RVR)
There are currently two configurations of RVR in the NAS commonly identified as Taskers and New Generation RVR. The Taskers are the existing configuration which uses transmissometer technology. The New Generation RVRs were deployed in Novem
- §7-1-14AIM — FAA OPERATIONAL GUIDANCE
7-1-14 — Reporting of Cloud Heights
a. Ceiling, by definition in the CFRs and as used in aviation weather reports and forecasts, is the height above ground (or water) level of the lowest layer of clouds or obscuring phenomenon that is reported as “broken,” “overcast,” or “obs
- §7-1-15AIM — FAA OPERATIONAL GUIDANCE
7-1-15 — Reporting Prevailing Visibility
a. Surface (horizontal) visibility is reported in METAR reports in terms of statute miles and increments thereof; e.g., 1/16, 1/8, 3/16, 1/4, 5/16, 3/8, 1/2, 5/8, 3/4, 7/8, 1, 1 1/8, etc. (Visibility reported by an unaugmented automated sit
- §7-1-16AIM — FAA OPERATIONAL GUIDANCE
7-1-16 — Estimating Intensity of Rain and Ice Pellets
a. Rain 1. Light. From scattered drops that, regardless of duration, do not completely wet an exposed surface up to a condition where individual drops are easily seen. 2. Moderate. Individual drops are not clearly identifiable; spray is o
- §7-1-17AIM — FAA OPERATIONAL GUIDANCE
7-1-17 — Estimating Intensity of Snow or Drizzle (Based on Visibility)
a. Light. Visibility more than 1/2 statute mile. b. Moderate. Visibility from more than 1/4 statute mile to 1/2 statute mile. c. Heavy. Visibility 1/4 statute mile or less.
- §7-1-18AIM — FAA OPERATIONAL GUIDANCE
7-1-18 — Pilot Weather Reports (PIREPs)
a. FAA air traffic facilities are required to solicit PIREPs when the following conditions are reported or forecast: ceilings at or below 5,000 feet; visibility at or below 5 miles (surface or aloft); thunderstorms and related phenomena; ic
- §7-1-19AIM — FAA OPERATIONAL GUIDANCE
7-1-19 — PIREPs Relating to Airframe Icing
a. The effects of ice on aircraft are cumulative‐thrust is reduced, drag increases, lift lessens, and weight increases. The results are an increase in stall speed and a deterioration of aircraft performance. In extreme cases, 2 to 3 inches
- §7-1-20AIM — FAA OPERATIONAL GUIDANCE
7-1-20 — Definitions of Inflight Icing Terms
See TBL 7-1-9, Icing Types, and TBL 7-1-10, Icing Conditions. Clear Ice | See Glaze Ice. Glaze Ice | Ice, sometimes clear and smooth, but usually containing some air pockets, which results in a lumpy translucent appearance. Glaze ice resul
- §7-1-21AIM — FAA OPERATIONAL GUIDANCE
7-1-21 — PIREPs Relating to Turbulence
a. When encountering turbulence, pilots are urgently requested to report such conditions to ATC as soon as practicable. PIREPs relating to turbulence should state: 1. Aircraft location. 2. Time of occurrence in UTC. 3. Turbulence intens
- §7-1-22AIM — FAA OPERATIONAL GUIDANCE
7-1-22 — Wind Shear PIREPs
a. Because unexpected changes in wind speed and direction can be hazardous to aircraft operations at low altitudes on approach to and departing from airports, pilots are urged to promptly volunteer reports to controllers of wind shear condi
- §7-1-23AIM — FAA OPERATIONAL GUIDANCE
7-1-23 — Clear Air Turbulence (CAT) PIREPs
CAT has become a very serious operational factor to flight operations at all levels and especially to jet traffic flying in excess of 15,000 feet. The best available information on this phenomenon must come from pilots via the PIREP reporti
- §7-1-24AIM — FAA OPERATIONAL GUIDANCE
7-1-24 — Microbursts
a. Relatively recent meteorological studies have confirmed the existence of microburst phenomenon. Microbursts are small scale intense downdrafts which, on reaching the surface, spread outward in all directions from the downdraft center. Th
- §7-1-25AIM — FAA OPERATIONAL GUIDANCE
7-1-25 — PIREPs Relating to Volcanic Ash Activity
a. Volcanic eruptions which send ash into the upper atmosphere occur somewhere around the world several times each year. Flying into a volcanic ash cloud can be extremely dangerous. At least two B747s have lost all power in all four engines
- §7-1-26AIM — FAA OPERATIONAL GUIDANCE
7-1-26 — Thunderstorms
a. Turbulence, hail, rain, snow, lightning, sustained updrafts and downdrafts, icing conditions-all are present in thunderstorms. While there is some evidence that maximum turbulence exists at the middle level of a thunderstorm, recent stud
- §7-1-27AIM — FAA OPERATIONAL GUIDANCE
7-1-27 — Thunderstorm Flying
a. Thunderstorm Avoidance. Never regard any thunderstorm lightly, even when radar echoes are of light intensity. Avoiding thunderstorms is the best policy. Following are some Do's and Don'ts of thunderstorm avoidance: 1. Don't land or tak
- §7-1-28AIM — FAA OPERATIONAL GUIDANCE
7-1-28 — Key to Aerodrome Forecast (TAF) and Aviation Routine Weather Report (METAR)
Key to Aerodrome Forecast (TAF) and Aviation Routine Weather Report (METAR) (Front) TAF | KPIT 091730Z 0918/1024 15005KT 5SM HZ FEW020 WS010/31022KT FM091930 30015G25KT 3SM SHRA OVC015 TEMPO 0920/0922 1/2SM +TSRA OVC008CB FM100100 27008KT
- §7-1-29AIM — FAA OPERATIONAL GUIDANCE
7-1-29 — International Civil Aviation Organization (ICAO) Weather Formats
The U.S. uses the ICAO world standard for aviation weather reporting and forecasting. The World Meteorological Organization's (WMO) publication No. 782 “Aerodrome Reports and Forecasts” contains the base METAR and TAF code as adopted by the
- §7-2-1AIM — FAA OPERATIONAL GUIDANCE
7-2-1 — General
a. Aircraft altimeters are subject to the following errors and weather factors: 1. Instrument error. 2. Position error from aircraft static pressure systems. 3. Nonstandard atmospheric pressure. 4. Nonstandard temperatures. b. The stan
- §7-2-2AIM — FAA OPERATIONAL GUIDANCE
7-2-2 — Barometric Pressure Altimeter Errors
a. High Barometric Pressure: Cold, dry air masses may produce barometric pressures in excess of 31.00 “Hg. Many aircraft altimeters cannot be adjusted above 31.00 “Hg. When an aircraft's altimeter cannot be set to pressure settings above 31