1. Special attention should be given to the parts which differ from U.S. CFRs. (a) The Canadian Airways Class B airspace restriction is an example. Class B airspace is all controlled low level airspace above 12,500 feet MSL or the MEA, whichever is higher, within which only IFR and controlled VFR flights are permitted. (Low level airspace means an airspace designated and defined as such in the Designated Airspace Handbook.) (b) Unless issued a VFR flight clearance by ATC, regardless of the weather conditions or the 2. Segments of VOR airways and high level routes in Canada are based on L/MF navigation aids and are charted in brown color instead of blue on en route charts. (d) VFR flight requires visual contact with the ground or water at all times. (c) The requirement for entry into Class B airspace is a student pilot permit (under the guidance or control of a flight instructor). height of the terrain, no person may operate an aircraft under VMC within Class B airspace. a. Pilots of aircraft are required to adhere to airways or routes being flown. Special attention must be given to this requirement during course changes. Each course change consists of variables that make the technique applicable in each case a matter only the pilot can resolve. Some variables which must be considered are turn radius, wind effect, airspeed, degree of turn, and cockpit instrumentation. An early turn, as illustrated below, is one method of adhering to airways or routes. The use of any available cockpit instrumentation, such as Distance Measuring Equip- ment, may be used by the pilot to lead the turn when making course changes. This  is consistent  with the intent of 14 CFR Section 91.181, which requires pilots to operate along the centerline of an airway and along the direct course between navigational aids or fixes. b. Turns which begin at or after fix passage may exceed airway or route boundaries. FIG 5 − 3 − 1 contains an example flight track depicting this, together with an example of an early turn. 5 − 3 − 5. Airway or Route Course Changes En Route Procedures 5 − 3 − 18 FIG 5 − 3 − 1 Adhering to Airways or Routes 8/15/19 3/15/07 12/31/20 AIM  7110.65R CHG 2 AIM