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AIM

10/12/17

5−3−26

En Route Procedures

(5) Some RNAV systems compute the

holding pattern based on the aircraft’s altitude and

speed at a point prior to entering the hold. If the

indicated airspeed is not reduced to comply with the

maximum holding speed before this point, the

computed pattern may exceed the protected airspace.

Loading or executing a holding pattern may result in

the speed and time limits applicable to the aircraft’s

current altitude being used to define the holding

pattern for RNAV lateral guidance. This may result in

an incorrect hold being flown by the RNAV system.

For example, entering or executing the holding

pattern above 14,000 feet when intending to hold

below 14,000 feet may result in applying 1 

½  minute

timing below 14,000 feet.

NOTE−

Some systems permit the pilot to modify leg time of  holding

patterns defined in the navigation database; for example,

a hold−in−lieu of procedure turn. In most RNAV systems,

the holding pattern time remains at the pilot−modified time

and will not revert back to the coded time if the aircraft

descends to a lower altitude where a shorter time interval

applies.

(b) RNAV systems are not able to alert the

pilot for excursions outside of holding pattern

protected airspace since the dimensions of this

airspace are not included in the navigation database.

In addition, the dimensions of holding pattern

protected airspace vary with altitude for a charted

holding pattern, even when the hold is used for the

same application. Close adherence to the pilot actions

described in this section reduce the likelihood of

exceeding the boundary of holding pattern protected

airspace when using RNAV lateral guidance to

conduct holding.

(c) Holding patterns may be stored in the

RNAV system’s navigation database and include

coding with parameters defining how the RNAV

system will conduct the hold. For example, coding

will determine whether holding is conducted to

manual termination (HM), continued holding until

the aircraft reaches a specified altitude (HA), or

holding is conducted until the holding fix is crossed

the first time after entry (HF). Some systems do not

store all holding patterns, and may only store patterns

associated with missed approaches and hold−in−lieu

of procedure turn (HILPT). Some store all holding as

standard patterns and require pilot action to conduct

non−standard holding (left turns).

(1) Pilots are cautioned that multiple

holding patterns may be established at the same fix.

These holding patterns may differ in respect to turn

directions and leg lengths depending on their

application as an en route holding pattern, a holding

pattern charted on a SID or STAR, or when used on

an instrument approach procedure. Many RNAV

systems limit the database coding at a particular fix to

a single holding pattern definition. Pilots extracting

the holding pattern from the navigation database are

responsible for confirming that the holding pattern

conforms to the assigned charted holding pattern in

terms of turn direction, speed limit, timing, and

distance.

(2) If ATC assigns holding that is not

charted, then the pilot is responsible for programming

the RNAV system with the assigned holding course,

turn direction, speed limit, leg length, or leg time.

(3) Changes made after the initial execu-

tion may not apply until the next circuit of the holding

pattern if the aircraft is in close proximity to the

holding fix.

8. Pilot Action. The following actions are

recommended to ensure that the aircraft remains

within holding protected airspace when holding is

performed using either conventional NAVAID

guidance or when using RNAV lateral guidance.

(a) Speed. When ATC furnishes advance

notice of holding, start speed reduction to be at or

below the maximum holding speed allowed at least 3

minutes prior to crossing the holding fix. If advance

notice by ATC is not provided, begin speed reduction

as expeditiously as practical. It is acceptable to allow

RNAV systems to determine an appropriate decelera-

tion point prior to the holding fix and to manage the

speed reduction to the RNAV computed holding

speed. If the pilot does not permit the RNAV system

to manage the deceleration from the computed point,

the actual hold pattern size at holding entry may differ

from the holding pattern size computed by the RNAV

system.

(1) Aircraft are expected to enter holding at

or below the maximum holding speed established in

paragraph 5−3−8 j 2(a) or the charted maximum

holding speed.

[a] All fixed wing aircraft conducting

holding should fly at speeds at or above 90 KIAS to

minimize the influence of wind drift.

3/15/07

7110.65R CHG 2

AIM

9/13/18