§ 135.609 VFR ceiling and visibility requirements for Class G airspace. ( a ) Unless otherwise specified in the certificate holder's operations specifications, when conducting VFR helicopter air ambulance operations in Class G airspace, the weather minimums in the following table apply:In uncontrolled airspace there is less risk of a VFR aircraft colliding with an instrument flight rules (IFR) aircraft emerging from a cloud, so aircraft are permitted to fly closer to clouds. An exception to this rule is class B airspace , in which ATC separates VFR traffic from all other traffic (VFR or IFR), which is why in class B airspace
Aircraft Speed. No person may operate an aircraft at or below 2,500' above the surface within 4NM of the primary airport of a Class D airspace area at an indicated airspeed of more than 200 knots. Class D. VFR Cloud Clearance. Flight Visibility. 3 statute miles. Distance from Clouds. 500 feet below. 1,000 feet above.
§ 91.119 Minimum safe altitudes: General. § 91.121 Altimeter settings. § 91.123 Compliance with ATC clearances and instructions. § 91.125 ATC light signals. § 91.126 Operating on or in the vicinity of an airport in Class G airspace. § 91.127 Operating on or in the vicinity of an airport in Class E airspace. § 91.129 Operations in Class DNormal VFR operations in Class D airspace with an operating control tower require the celing and visibility to be at least A - 1,000 feet and 1 mile B - 1,000 feet and 3 miles C - 2,500 feet and 3 miles TlCYbeD.