Section 1. General

3/29/18 10/12/17 AIM Chapter 3. Airspace Section 1. General 3−1−1. General a. There are two categories of airspace or airspace areas: 1. Regulatory (Class A, B, C, D and E airspace areas, restricted and prohibited areas); and 2. Nonregulatory (military operations areas [MOA], warning areas, alert areas, controlled firing areas [CFA], and national security areas [NSA]). 3−1−2. General Dimensions of Airspace Segments Refer to Code of Federal Regulations (CFR) for specific dimensions, exceptions, geographical areas covered, exclusions, specific transponder or equipment requirements, and flight operations. 3−1−3. Hierarchy of Overlapping Airspace Designations a. When overlapping airspace designations apply to the same airspace, the operating rules associated with the more restrictive airspace designation apply. NOTE− Additional information on special use airspace (prohibited areas, restricted areas [permanent or temporary], warning areas, MOAs [permanent or temporary], alert areas, CFAs, and NSAs) may be found in Chapter 3, Airspace, Section 4, Special Use Airspace, paragraphs 3−4−1 through 3−4−8 . 1. Class A airspace is more restrictive than Class B, Class C, Class D, Class E, or Class G airspace; b. Within these two categories, there are four types: 2. Class B airspace is more restrictive than Class C, Class D, Class E, or Class G airspace; b. For the purpose of clarification: 1. Controlled, 3. Class C airspace is more restrictive than Class D, Class E, or Class G airspace; 2. Uncontrolled, 4. Class D airspace is more restrictive than Class E or Class G airspace; and 3. Special use, and 4. Other airspace. c. The categories and types of airspace are dictated by: 1. The complexity or density of aircraft movements, 2. The nature of the operations conducted within the airspace, 3. The level of safety required, and 4. The national and public interest. d. It is important that pilots be familiar with the operational requirements for each of the various types or classes of airspace. Subsequent sections will cover each class in sufficient detail to facilitate understanding. General 5. Class E is more restrictive than Class G airspace. 3−1−4. Basic VFR Weather Minimums a. No person may operate an aircraft under basic VFR when the flight visibility is less, or at a distance from clouds that is less, than that prescribed for the corresponding altitude and class of airspace. (See TBL 3−1−1.) NOTE− Student pilots must comply with 14 CFR Section 61.89(a) (6) and (7). b. Except as provided in 14 CFR Section 91.157, Special VFR Weather Minimums, no person may operate an aircraft beneath the ceiling under VFR within the lateral boundaries of controlled airspace designated to the surface for an airport when the ceiling is less than 1,000 feet. (See 14 CFR Section 91.155(c).) 3−1−1 AIM 10/12/17 TBL 3−1−1 Basic VFR Weather Minimums Airspace Flight Visibility Class A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Not Applicable Class B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 statute miles Class C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 statute miles Class D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 statute miles Class E Less than 10,000 feet MSL . . . . . . . . . . . . . . . . . . . . . . . . 3 statute miles At or above 10,000 feet MSL . . . . . . . . . . . . . . . . . . . . . . 5 statute miles Class G 1,200 feet or less above the surface (regardless of MSL altitude). Day, except as provided in section 91.155(b) . . . . . . . . . . 1 statute mile Night, except as provided in section 91.155(b) . . . . . . . . . 3 statute miles More than 1,200 feet above the surface but less than 10,000 feet MSL. Day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 statute mile Night . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 statute miles More than 1,200 feet above the surface and at or above 5 statute miles 10,000 feet MSL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Distance from Clouds Not Applicable Clear of Clouds 500 feet below 1,000 feet above 2,000 feet horizontal 500 feet below 1,000 feet above 2,000 feet horizontal 500 feet below 1,000 feet above 2,000 feet horizontal 1,000 feet below 1,000 feet above 1 statute mile horizontal Clear of clouds 500 feet below 1,000 feet above 2,000 feet horizontal 500 feet below 1,000 feet above 2,000 feet horizontal 500 feet below 1,000 feet above 2,000 feet horizontal 1,000 feet below 1,000 feet above 1 statute mile horizontal 3−1−5. VFR Cruising Altitudes and Flight Levels (See TBL 3−1−2.) TBL 3−1−2 VFR Cruising Altitudes and Flight Levels If your magnetic course (ground track) is: 0 to 179 . . . . . . . . . . . . . . . . 180 to 359 . . . . . . . . . . . . . . 3−1−2 And you are more than 3,000 feet above the surface but below 18,000 feet MSL, fly: Odd thousands MSL, plus 500 feet (3,500; 5,500; 7,500, etc.) Even thousands MSL, plus 500 feet (4,500; 6,500; 8,500, etc.) And you are above 18,000 feet MSL to FL 290, fly: Odd Flight Levels plus 500 feet (FL 195; FL 215; FL 235, etc.) Even Flight Levels plus 500 feet (FL 185; FL 205; FL 225, etc.) General