Notes from the Instrument Procedures Handbook – Departure Weather
FAA-H-8083-16 Instrument Procedures Handbook
Chapter 1 Departures
Takeoff Minimums
Takeoff minimums are typically lower than published landing minimums, and ceiling requirements are only included if it is necessary to see and avoid obstacles in the departure area.
The FAA establishes takeoff minimums for every airport that has published Standard Instrument Approaches. These minimums are used by commercially operated aircraft, namely Part 121 and Part 135 operators.
FAA designated standard minimums: 1 statute mile (SM) visibility for single- and twin-engine aircraft, and 1⁄2 SM for helicopters and aircraft with more than two engines.
Aircraft operating under 14 CFR Part 91 are not required to comply with established takeoff minimums. Legally, a zero/ zero departure may be made, but it is never advisable.
If an airport has non-standard takeoff minimums, a 
is placed in the notes sections of the instrument procedure chart. In the front of the TPP booklet, takeoff minimums are listed before the obstacle departure procedure.
Ceiling and Visibility Requirements
All takeoffs and departures have visibility minimums (some may have minimum ceiling requirements) incorporated into the procedure.
Visibility
Visibility is the ability, as determined by atmospheric conditions and expressed in units of distance, to see and identify prominent unlighted objects by day and prominent lighted objects by night. Visibility is reported as statute miles, hundreds of feet, or meters.
Prevailing Visibility
Prevailing visibility is the greatest horizontal visibility equaled or exceeded throughout at least half the horizon circle, which need not necessarily be continuous. Prevailing visibility is reported in statute miles or fractions of miles.
Runway Visibility Value (RVV)
Runway visibility value is the visibility determined for a particular runway by a transmissometer. A meter provides continuous indication of the visibility (reported in statute miles or fractions of miles) for the runway. RVV is used in lieu of prevailing visibility in determining minimums for a particular runway.
Tower Visibility
Tower visibility is the prevailing visibility determined from the airport traffic control tower at locations that also report the surface visibility.
Runway Visual Range (RVR)
Runway visual range is an instrumentally derived value, based on standard calibrations, that represents the horizontal distance a pilot sees down the runway from the approach end. RVR, in contrast to prevailing or runway visibility, is based on what a pilot in a moving aircraft should see looking down the runway.
Ceilings
Ceiling is the height above the earth’s surface of the lowest layer of clouds or obscuring phenomena that is reported as broken, overcast, or obscuration and not classified as thin or partial.
IFR Alternate Requirements
On AeroNav Products charts, standard alternate minimums are not published. If the airport has other than standard alternate minimums, they are listed in the front of the approach chart booklet.
For airplane 14 CFR Part 91 requirements, an alternate airport must be listed on IFR flight plans if the forecast weather at the destination airport, for at least 1 hour before and for 1 hour after the estimated time of arrival (ETA), the ceiling is less than 2,000 feet above the airport elevation, and the visibility is less than 3 SM.
For an airport to be used as an alternate, the forecast weather at that airport must meet certain qualifications at the ETA. Standard airplane alternate minimums for a precision approach are a 600-foot ceiling and a 2 SM visibility. For a non-precision approach, the minimums are an 800-foot ceiling and a 2 SM visibility.