Definition
A subsection of Title 14 of the Code of Federal Regulations, Part 91, Section 155, which establishes special VFR weather minimums for helicopters. Under §91.155(b), helicopters operating under VFR in Class G airspace at or below 1,200 feet above the surface during the day may operate clear of clouds with less than 1 statute mile flight visibility, provided the helicopter is operated at a speed that allows the pilot adequate opportunity to see and avoid other aircraft and obstructions in time to prevent a collision.
Plain English
This is the rule that lets helicopters fly in lower visibility than airplanes, as long as they stay clear of clouds and fly slow enough to spot and avoid other traffic and obstacles in time.
Context Anchor
Seen in the Instrument Procedures Handbook under Helicopter VFR Minimums and in preflight decisions about helicopter operations in low-level Class G airspace.
Derivation
The § symbol means 'section' and comes from the Latin signum sectionis. The numbering follows the Code of Federal Regulations format: Part 91, Section 155, paragraph (b). Knowing this helps you read any FAR citation — the number before the period is the part, after the period is the section, and lettered paragraphs subdivide the rule.
Why Pilots Care
Helicopter pilots rely on this paragraph to confirm they meet legal weather minimums before departing on a VFR flight; operating below these values without an instrument clearance can result in a violation or unsafe flight.
Analogy
The citation works like an exact address in the rulebook: Part 91 is the area, §91.155 is the rule, and (b) is the specific paragraph.
Grounding Statement
Picture a helicopter moving slowly below a low cloud layer in low-level uncontrolled airspace: §91.155(b) is the rule that makes the operation depend on staying out of clouds and being able to see hazards in time.
Intuition Check
Do not read §91.155(b) as a blanket permission to fly in bad weather. It is a narrow rule for specific low-level airspace, and the helicopter must still stay out of clouds and be flown slowly enough to avoid traffic and obstacles.
Example Sentence 1
Operating under §91.155(b), the EMS pilot reduced airspeed in the reduced visibility to maintain adequate time to see and avoid terrain and other aircraft.
Example Sentence 2
The briefing highlighted that §91.155(b) allows helicopters to operate with lower ceilings than airplanes in certain uncontrolled airspace.