Figure 2-23. Special visual flight rule altitude assignment phraseology
f. Climb to Visual Flight Rule
When requested by the pilot, authorize an aircraft to climb to VFR on request if the only weather
limitation is restricted visibility.
g. Ground Visibility Below One Mile
When the ground visibility is officially reported at an airport as less than one mile, treat a request
for SVFR operations at that airport by other than helicopters as follows:
NOTE: FAR 91 does not prohibit helicopter SVFR flights when visibility is less than one mile.
(1) Inform departing aircraft that ground visibility is less than one mile and that a clearance
cannot be issued.
(2) Inform arriving aircraft operating outside the control zone that ground visibility is less than
one mile and that, unless an emergency exists, a clearance cannot be issued.
(3) Inform arriving aircraft operating within the control zone that ground visibility is less than
one mile. Ask if the aircraft can depart the control zone with a flight visibility of a least one mile. If the
reply is "Yes," issue a clearance out of the control zone. If the reply is "No" or an emergency exists,
issue a clearance as soon as traffic conditions permit.
(4) Authorize scheduled air carrier aircraft in the United States to conduct operations if ground
visibility is NOT less than one-half statute mile.
(5) Clear an aircraft to fly through the control zone if he reports flight visibility is at least one