Weather Judgment – Go or No-Go

Aviation Weather and Pilot Judgement

Judgment, often defined as the ability to arrive at a wise decision, is the combination of knowledge and skill, tempered by experience. Studies show that pilot judgment can, in large part, be learned, and that
learning process starts with sound pilot education.

Personal Weather Minimums

In aviation, you can also improve your “Go or No-Go” weather judgment by setting personal weather minimums based on your level of training and experience.

For instance, using a personal minima of 2,000 and five instead of the regulatory VFR minimums of 1,000 and three. You may then gradually reduce your personal minimums to whatever limits you find comfortable, at or above the legal limits. And while we are on the subject of pilot judgment, it is reasonably obvious that pilots can’t make good decisions based upon incomplete, or missing information. Knowing what is going on around you is called situational awareness.

[perfectpullquote align=”full” bordertop=”false” cite=”” link=”” color=”” class=”” size=””]It is the combination of situational awareness and sound pilot judgment that is the key to safe flying.[/perfectpullquote]

Here are some safety-related “DON’Ts” for everyone – beginner and pro alike:

  • DON’T fly in or near thunderstorms.

Scattered thunderstorms may be safely circumnavigated, but do not try to fly through or under one.

  • DON’T continue VFR into Instrument Meteorological Conditions (IMC).

Wait it out or turn around if you find enroute weather lowering below your personal limits.

  • DON’T forget there may be areas en route, or even near airports, which are below VFR minimums, even though reporting stations are at or near VFR minimums.

Be especially cautious when the temperature and dew point spread is 3°C or less – fog may form.

  • DON’T proceed “on-top,” hoping to find a hole in the clouds at the other end, or hoping to get Air Traffic Control (ATC) to “talk you down” if you get caught on top.

Allow more margin for weather at night. Scud, lower clouds, and even the horizon may be difficult or impossible to see on dark nights. And always stay above the highest terrain, until a safe landing is assured.

  • DON’T fly into areas of rain when the air temperature is near freezing.

Ice can form on the windshield impairing forward vision and/or, worse, on the wings decreasing aircraft performance. Remember, flight into known icing conditions is prohibited for all aircraft not properly certificated for flight in icing conditions or not properly equipped with anti-icing equipment.

  • And finally, if you do get caught in weather, immediately contact Flight Watch or Flight Service or any available ATC facility.

They will do their utmost to assist you.


Note: The 3 hours of required training in FAR 61.109 (a) (3) towards Private Pilot training is not sufficient to safely fly in lowered visibility conditions. Don’t let that fool you into developing false sense of security. Unintentional VFR flights into IMC conditions are usually fatal.

Good Aviation Weather Briefing – The Basics

A good weather briefing starts with developing total awareness of the overall “big picture” prior to obtaining a detailed or standard briefing. Most pilots start by monitoring weather patterns via TV’s The Weather Channel several days before the flight. The day or evening before the flight, pilots may wish to obtain an outlook briefing from Flight Service Station (FSS), or electronically from a Direct User Access Terminal (DUAT) vendor, or downloading weather and forecast charts from the Internet. (When using DUATs don’t hesitate to contact Flight Service Station to clarify any information you do not fully understand.)

As close to departure time as possible, call Flight Service Station or log on to DUATs for a standard briefing. Of course, you can access high-quality weather products on the Internet nowadays, but make sure that they are suitable for aviation use, and the products are current. If a standard briefing was obtained several hours prior to the flight, or when the weather is questionable, it is a good practice to call a Flight Service Station for an abbreviated briefing just prior to takeoff.

The FAA has established a universal toll-free telephone number for Flight Service Stations: 1-800 WX BRIEF (1-800-992-7433). Prior to contacting FSS you should have your general route of flight worked out. When you reach FSS, you will be answered by a recorded announcement, followed by instructions for both touch-tone and rotary dial telephone users. Touch-tone users can elect to speak with a briefer, listen to any of the direct-access services, or select a menu which identifies those services and their Associated codes. The direct-access services are Telephone Information Briefing Service (TIBS) for weather and aeronautical information, and “fastfile” for flight plan filing. If you are using a rotary dial or pulse-tone equipped telephone, you will be switched automatically to a weather briefer, who will provide the information desired; or if requested, connect you to one of the direct-access services.

To help the briefer provide you with the best service, state your request (i.e., request: a standard, abbreviated, or outlook briefing; or to file a flight plan). So that your briefing can be tailored to your needs,
provide the briefer with the following “background information”:

  • Your qualifications (e.g., student, private, or commercial pilot, and if instrument rated)
  • The type of flight planned (e.g., VFR or IFR)
  • The aircraft’s N-number or Pilot’s name
  • The aircraft type
  • Departure point
  • Estimated time of departure
  • Proposed flight altitude(s)
  • Proposed route-of-flight, if other than direct; specify any landing en route
  • Destination, and
  • Estimated time en route

Ask the briefer to provide a standard briefing. This briefing will follow specific procedures and use standard phraseology developed by FAA flight services personnel. The briefer will first advise you of any adverse conditions along your proposed route of flight. When a VFR flight is proposed, and actual or forecast conditions make VFR flight questionable, the briefer will describe the conditions and may advise you that “VFR flight (is) not recommended.” If this occurs you are still entitled to a complete briefing; however, if you feel that the weather conditions are beyond your capabilities or that of your aircraft or equipment, you should consider terminating the briefing, and your flight. This will free the briefer to handle other incoming calls. Just because the briefer does not issue this statement does not necessarily guarantee a flight free from adverse weather effects. Phenomena such as thunderstorms, turbulence, mountain obscurations, and strong winds do not, in and of themselves, warrant this statement. Only you as a pilot-in-command know your own capabilities and limitations.

Briefers will typically summarize weather reports and forecasts, unless you specifically request that they be read verbatim. Try not to interrupt the briefer unless the briefer is speaking too fast. At the conclusion of the briefing ask for any additional information you may require, or for clarification of any point you do not completely understand. The amount of detail in your weather briefing will depend upon the complexity of the weather situation. It is both your responsibility and prerogative as a pilot to obtain a standard briefing.

Types of Aviation Weather Briefings

Standard Briefing

The standard preflight briefing will include the following elements:

  • Adverse Conditions: Significant meteorological information that might influence you, the pilot, to alter your proposed route of flight, or even cancel your planned flight entirely (e.g., thunderstorms, icing, turbulence, low ceilings or visibility)
  • Synopsis: A brief statement as to the cause of the weather (e.g., fronts or pressure systems) which are pertinent to your proposed route-of-flight
  • Current Conditions: When your proposed time of departure is within two hours, a summary of the current weather, including Pilot Weather Reports (PIREPs) and radar weather information applicable to your planned flight
  • En Route Forecast: The briefer will summarize the forecast conditions (unless requested to read the forecasts verbatim) along your proposed route in a logical order (i.e., climb- out, enroute, and descent)
  • Destination Forecast: The destination forecast for your planned ETA will be provided, including any significant changes expected within one hour of your planned time of arrival
  • Winds Aloft: The briefer will summarize forecast winds aloft for the proposed route. Temperature information will be provided on request; and
  • Notice to Airmen (NOTAMs): “Current” NOTAMs pertinent to your proposed route of flight will be provided. However, information on Global Positioning System (GPS) outages, Long Range Navigation (LORAN), and military training routes and areas (e.g., Military Training Routes (MTRs) and Military Operations Areas (MOAs)), along with PUBLISHED NOTAMs must be specifically requested. (When requesting the status of MTRs and MOAs please provide the briefer with the route number identifier or MOA name.) It is always good judgment to inquire whether the briefer has access to all military activity along your proposed route, or whether you will also need to contact another Flight Service Station (on standard FSS radio frequencies) along your route-of-flight to check on the activity and status of designated military areas.

Abbreviated Briefing

Request an Abbreviated Briefing when you need information to supplement other electronically acquired data (e.g., TIBS or DUATs), update a previous briefing, or when you need only one or two specific items. Provide the briefer with appropriate background information, the time you received the previous information, and the specific items needed. You should indicate the source of the information already received so that the briefer can limit the briefing to the information that you have not received, and provide appreciable changes
in meteorological conditions or aeronautical information since your previous briefing. To the extent possible, the briefer will provide the information in the sequence used in a Standard Briefing. If you request only one or two specific items, the briefer is required to advise you if adverse conditions are present or forecast. Details on these conditions will be provided at your request. Often, and especially when doing local flying, you may want to update the weather at a specific airport. You can do this by directly dialing an automated
weather system, if available, at that airport.

Outlook Briefing

You should request an Outlook Briefing whenever your proposed time of departure is six or more hours in the future. In this case, the briefer will provide you with available forecast data applicable to your proposed departure time. This type of briefing is provided for planning purposes only. You should obtain a Standard Briefing as close to departure as possible in order to obtain the latest current conditions, forecasts, and NOTAMs. Often, graphical weather depiction’s obtained through DUATs or the Internet can provide excellent trend information and so may be used accordingly.

In-flight Briefing

If at all possible, obtain a preflight briefing by telephone or by electronic means prior to departure. In cases when you are already in flight and you need to obtain a standard briefing or update a previous briefing in-flight, you should contact Flight Service not Flight Watch. After contact, you should advise the specialist of the type of briefing you require and provide appropriate background information. You will then be provided information as specified in the above paragraphs, depending on the type of briefing requested. The FLIGHT WATCH service is not meant to provide you with a full standard briefing. Rather, rely on FLIGHT WATCH to provide you with the most current en route weather. And when using FLIGHT WATCH, always give a PIREP so other pilots may benefit from your reports of the weather, ride, etc.

In-flight Data Linked Weather

Technology advancements now allow suitably equipped aircraft to receive textual and graphical data linked weather products and other information. However, just like weather information received over the Internet, it is imperative (and even more so in-flight) that the pilot use the most current information, not out-of-date or invalid weather products. Also remember while airborne, to judiciously spread your time between “head in the cockpit” and “outside” watching for other traffic. That is good judgment!