4.
Radar Vectors
4.1
Controllers may vector aircraft within CON-TROLLED AIRSPACE for separation purposes, noise abatement considerations, when an operational advantage will be realize by the pilot or the controller, or when requested by the pilot. Vectors outside of CONTROLLED AIRSPACE will be provided only on pilot request. Pilots will be advised as to what the vector is to achieve when the vector is controller initiated and will take the aircraft off a previously assigned nonradar route. To the extent possible, aircraft operating on RNAV routes will be allowed to remain on their own navigation.
5.
Changeover Points (COPs)
5.1 COPs are prescribed for Federal airways, jet routes, area navigation routes, or other direct routes for which an minimum en route altitude (MEA) is designated under 14 CFR Part 95. The COP is a point along the route or airway segment between two adjacent navigation facilities or waypoints where changeover navigation guidance should occur. At this point, the pilot should change navigation receiver frequency from the station behind the aircraft to the station ahead.
5.2 The COP is normally located midway between the navigation facilities for straight route segments, or at the intersection of radials or courses forming a dogleg in the case of dogleg route segments. When the COP is NOT located at the midway point, aeronautical charts will depict the COP location and give the mileage to the radio aids.
5.3
COPs are established for the purpose of preventing loss of navigation guidance, to prevent frequency interference from other facilities, and to prevent use of different facilities by different aircraft in the same airspace. Pilots are urged to observe COPs to the fullest extent.
6.
Airway or Route Course Changes
6.1 Pilots of aircraft are required to adhere to airways/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 in FIG ENR 3.5.1, is one method of adhering to airways/routes. The use of any available cockpit instrumentation, such as distance measuring equipment, 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.
6.2 Turns which begin at or after fix passage may exceed airway/route boundaries. FIG ENR 3.5.1 contains an example flight track depicting this, together with an example of an early turn.
FIG ENR 3.5.1
Adhering to Airways or Routes
6.3 Without such actions, as leading a turn, aircraft operating in excess of 290 knots true airspeed (TAS) can exceed the normal airway/route boundaries depending on the amount of course change required, wind direction and velocity, the character of the turn fix, (DME, overhead navigation aid, or intersection), and the pilot’s technique in making a course change. For example, a flight operating at 17,000 feet MSL with a TAS of 400 knots, a 25 degree bank, and a course change of more than 40 degrees would exceed the width of the airway/route; i.e., 4 nautical miles each side of centerline. However, in the airspace below 18,000 feet MSL, operations in excess of 290 knots TAS are not prevalent and the provision of additional IFR separation in all course change situations for the occasional aircraft making a turn in excess of 290 knots TAS creates an unacceptable waste of airspace and imposes a penalty upon the preponderance of traffic which operates at low speeds. Consequently, the FAA expects pilots to lead turns and take other actions they consider necessary during the course changes to adhere as closely as possible to the airways or route being flown.
Federal Aviation Administration Twentieth Edition
ENR 4. NAVIGATION AIDS/SYSTEMS
ENR 4.1 Navigation Aids . En Route
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