TACAN Holding

T-34C INSTRUMENTS

CHAPTER SIX

APP CONT:

"Navy _____ ,_____ Approach, hold as published at the Initial

Approach Fix (or IAF Name) for the TACAN RWY 17/23 approach at destination.

Time now 57, expected further clearance time 20, destination weather, 900 broken,

visibility 2 miles with light rain, altimeter 30.06, duty runway ____." (Figures 630

and 631).

The holding clearance, if not "hold as published," will specify the length of the legs.

NOTE

If the holding fix is on an airway, you may not be assigned a

holding radial. Use the radial that defines the airway. When

holding on an airway expect either a one minute (timed) pattern or

leg lengths as specified by ATC.

A sample clearance:

APP CONT:

"Navy, Center, hold south of REDDI on V115, use three mile legs,

time now 57, expected further clearance at time 20." (Figure 632).

Turns are commenced upon reaching specified DMEs (timing is not involved if the

leg lengths are specified by DME). Your radius of turn will carry you slightly

beyond these points. ATC is aware of this.

When turning to intercept the inbound course in TACAN holding, an intercept

greater than "doubletheangle" will be needed. Normally a 30 to 45 degree angle

of intercept will establish the aircraft on the inbound course. Lead the turn to

establish the aircraft on the inbound course. This is to compensate for the greater

spacing between radials when holding away from the station. For example, at 2 NM

from the station, a 6 course error represents onefifth NM off course. Twenty NM

from the station, the same 6 course is 2 NM off course. Discuss with your

instructor the appropriate amount of intercept under varying circumstances.

Determine wind direction using the same method from VOR station holding (TAIL

RADIALWIND). During VOR holding, the number of degrees of crab, used on

the outbound leg, equals the number of degrees off course after the inbound turn on

the nowind orbit. This will not work as well in TACAN holding, again due to the

greater radial spacing further from the station.

The following method will aid in determining wind corrections during TACAN holding.

Refer to Figure 629. Here the aircraft is holding between 12 to 15 DME on the 45

radial.

Determine the outermost leg length - in this case 15 DME.

ii.

Determine the length of the holding pattern - 3 NM.

RADIO INSTRUMENT FLIGHT PROCEDURES 6-47