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AIM

10/12/17

5−3−18

En Route Procedures

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.

c. Without such actions as leading a turn, aircraft

operating in excess of 290 knots true air speed (TAS)

can exceed the normal airway or 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 or 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 operate at low speeds.

Consequently, the FAA expects pilots to lead turns

and take other actions they consider necessary during

course changes to adhere as closely as possible to the

airways or route being flown.

5−3−6. Changeover Points (COPs)

a. COPs are prescribed for Federal airways, jet

routes, area navigation routes, or other direct routes

for which an 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 in navigation guidance

should occur. At this point, the pilot should change

navigation receiver frequency from the station

behind the aircraft to the station ahead.

b. 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.

c. 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.

5−3−7. Minimum Turning Altitude (MTA)
Due to increased airspeeds at 10,000 ft MSL or above,

the published minimum enroute altitude (MEA) may

not be sufficient for obstacle clearance when a turn is

required over a fix, NAVAID, or waypoint. In these

instances, an expanded area in the vicinity of the turn

point is examined to determine whether the published

MEA is sufficient for obstacle clearance. In some

locations (normally mountainous), terrain/obstacles

in the expanded search area may necessitate a higher

minimum altitude while conducting the turning

maneuver. Turning fixes requiring a higher minimum

turning altitude (MTA) will be denoted on

government charts by the minimum crossing altitude

(MCA) icon (“x” flag) and an accompanying note

describing the MTA restriction. An MTA restriction

will normally consist of the air traffic service (ATS)

route leading to the turn point, the ATS route leading

from the turn point, and the required altitude; e.g.,

MTA V330 E TO V520 W 16000. When an MTA is

applicable for the intended route of flight, pilots must

ensure they are at or above the charted MTA not later

than the turn point and maintain at or above the MTA

until joining the centerline of the ATS route following

the turn point. Once established on the centerline

following the turning fix, the MEA/MOCA deter-

mines the minimum altitude available for

assignment. An MTA may also preclude the use of a

specific altitude or a range of altitudes during a turn.

For example, the MTA may restrict the use of 10,000

through 11,000 ft MSL. In this case, any altitude

greater than 11,000 ft MSL is unrestricted, as are

altitudes less than 10,000 ft MSL provided

MEA/MOCA requirements are satisfied.

3/15/07

7110.65R CHG 2

AIM

9/13/18