background image

AIM

10/12/17

5−3−25

En Route Procedures

outbound turns. An aircraft’s flight guidance system

may use reduced bank angles for all turns including

turns in holding, especially at higher altitudes, that

may result in exceeding holding protected airspace.

Use of a shallower bank angle will expand both the

width and length of the aircraft track, especially as

wind speed increases. If the flight guidance system’s

bank angle limit feature is pilot−selectable, a

minimum 25 degree bank angle should be selected

regardless of altitude unless aircraft operating

limitations specify otherwise and the pilot advises

ATC.

(4) Where a holding distance is published,

the turn from the outbound leg begins at the published

distance from the holding fix, thus establishing the

design turn point required to remain within protected

airspace. RNAV systems apply a database coded or

pilot−entered leg distance as a maximum length of the

inbound leg to the holding fix. The RNAV system

then calculates a turn point from the outbound leg

required to achieve this inbound leg length. This often

results in an RNAV−calculated turn point on the

outbound leg beyond the design turn point. (See

FIG 5−3−8). With a strong headwind against the

outbound leg, RNAV systems may fly up to and

possibly beyond the limits of protected airspace

before turning inbound. (See FIG 5−3−9.) This is

especially true at higher altitudes where wind speeds

are greater and ground speed results in a wider

holding pattern.

FIG 5−3−8

RNAV Lateral Guidance and Holding – No Wind 

FIG 5−3−9

RNAV Lateral Guidance and Holding – Effect of Wind

9/13/18

AIM