Timed Approaches from a Holding Fix — AIM 5-4-10 Explained

AIM Text

TIMED APPROACHES may be conducted when the following conditions are met:
1. A control tower is in operation at the airport where the approaches are conducted.
2. Direct communications are maintained between the pilot and the center or approach controller until the pilot is instructed to contact the tower.
3. If more than one missed approach procedure is available, none require a course reversal.
4. If only one missed approach procedure is available, the following conditions are met:
  1. Course reversal is not required; and,
  2. Reported ceiling and visibility are equal to or greater than the highest prescribed circling minimums for the IAP.
5. When cleared for the approach, pilots must not execute a procedure turn. (14 CFR section 91.175.)
Although the controller will not specifically state that “timed approaches are in use,” the assigning of a time to depart the final approach fix inbound (nonprecision approach) or the outer marker or fix used in lieu of the outer marker inbound (precision approach) is indicative that timed approach procedures are being utilized, or in lieu of holding, the controller may use radar vectors to the Final Approach Course to establish a mileage interval between aircraft that will ensure the appropriate time sequence between the final approach fix/outer marker or fix used in lieu of the outer marker and the airport.
Each pilot in an approach sequence will be given advance notice as to the time they should leave the holding point on approach to the airport. When a time to leave the holding point has been received, the pilot should adjust the flight path to leave the fix as closely as possible to the designated time. (See FIG 5-4-19.)
FIG 5-4-19
Timed Approaches from a Holding Fix

EXAMPLE-
At 12:03 local time, in the example shown, a pilot holding, receives instructions to leave the fix inbound at 12:07. These instructions are received just as the pilot has completed turn at the outbound end of the holding pattern and is proceeding inbound towards the fix. Arriving back over the fix, the pilot notes that the time is 12:04 and that there are 3 minutes to lose in order to leave the fix at the assigned time. Since the time remaining is more than two minutes, the pilot plans to fly a race track pattern rather than a 360 degree turn, which would use up 2 minutes. The turns at the ends of the race track pattern will consume approximately 2 minutes. Three minutes to go, minus 2 minutes required for the turns, leaves 1 minute for level flight. Since two portions of level flight will be required to get back to the fix inbound, the pilot halves the 1 minute remaining and plans to fly level for 30 seconds outbound before starting the turn back to the fix on final approach. If the winds were negligible at flight altitude, this procedure would bring the pilot inbound across the fix precisely at the specified time of 12:07. However, if expecting headwind on final approach, the pilot should shorten the 30 second outbound course somewhat, knowing that the wind will carry the aircraft away from the fix faster while outbound and decrease the ground speed while returning to the fix. On the other hand, compensating for a tailwind on final approach, the pilot should lengthen the calculated 30 second outbound heading somewhat, knowing that the wind would tend to hold the aircraft closer to the fix while outbound and increase the ground speed while returning to the fix.

Source: FAA Aeronautical Information Manual · current edition · paragraph 5-4-10.

Research Notes

AIM 5-4-10 covers Timed Approaches from a Holding Fix — the approach technique when multiple aircraft are sequenced from a holding fix.

The scenario: Multiple IFR aircraft are holding at a fix. ATC sequences them onto the approach at specific times. The first aircraft commences the approach; the next aircraft commences when authorized by ATC at the proper interval.

Pilot's responsibility: Comply with the sequencing time. Begin the approach descent at the assigned time. Don't anticipate by starting early.

Modern context: Less common today as RNAV and radar vectoring have largely replaced timed-approach techniques. Still used at some airports during weather-induced backup.

Reference: AIM 5-4-10; FAA-H-8083-16 Chapter 5.

5-4-10. Timed Approaches from a Holding Fix

AIM Text

FIG 5-4-19
Timed Approaches from a Holding Fix

Research Notes

This free course covers everything you need to get started the right way.

AIM Text

FIG 5-4-19 Timed Approaches from a Holding Fix

Research Notes

This free course covers everything you need to get started the right way.

FIG 5-4-19
Timed Approaches from a Holding Fix