I have tried to find what timed approach is, but I cannot find any reference to it. Could you let me know what it is and when it is used?
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I had never heard of this or seen an approach with a holding fix at the FAF or outer marker when I ran across a question on timed approaches from a holding fix in Gardner’s Complete Advanced Pilot. As you can see from the quotes at the bottom of the post, it is unlikely to ever be used. But they are still available to the controller, FAA Order JO 7110.65W Air Traffic Control.
FAA_H_8083-15B Instrument Flying Handbook 2012
Timed approaches from a holding fix are conducted when many aircraft are waiting for an approach clearance. Although the controller does not specifically state “timed approaches are in progress,” the assigning of a time to depart the FAF inbound (nonprecision approach), or the outer marker or fix used in lieu of the outer marker inbound (precision approach), indicates that timed approach procedures are being utilized.
In lieu of holding, the controller may use radar vectors to the final approach course to establish a distance between aircraft that ensures the appropriate time sequence between the FAF and outer marker or fix used in lieu of the outer marker and the airport. Each pilot in the approach sequence is given advance notice of the time they should leave the holding point on approach to the airport. When a time to leave the holding point is received, the pilot should adjust the flightpath in order to leave the fix as closely as possible to the designated time.
Timed approaches may be conducted when the following conditions are met:
A control tower is in operation at the airport where the approaches are conducted.
Direct communications are maintained between the pilot and the Center or approach controller until the pilot is instructed to contact the tower.
If more than one MAP is available, none require a course reversal.
If only one MAP is available, the following conditions are met:
a) Course reversal is not required; and
b) Reported ceiling and visibility are equal to or greater than the highest prescribed circling minimums for the IAP.
When cleared for the approach, pilots should not execute a procedure turn.
The actual order specifies that Timed approaches using either nonradar procedures or radar vectors to the final approach course may be used at airports served by a tower if the following conditions are met and goes on to give similar conditions.
The AIM has an example of how they might be used.
The sons of the guys who wrote that procedure are now in the “Old Controllers’ Home”, I can only guess at their intent. The last time I had to run timed approaches was when I was taking non-radar problems to certify on Denver Sector 26 (COS/PUB low) in 1968! R Butler – ATC Controller
We did some timed approaches when I worked a U.S. non-radar approach control in the ’80s. Don’t believe there are any non-radar approach controls left, and I don’t know a single radar controller who would try it if there were a radar outage of some sort. We also had to run them at the FAA Academy in training back in the ’70s. You would need to assign different missed approaches to succeeding aircraft, so #2 doesn’t catch #1 on the miss.
It’s a lot of radio and brain work to do successfully. Non-radar at a radar facility, (because of an outage) is usually very limited now. (One in, one out) Backup radar systems preferred, even if not as accurate. vector4fun
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1$\begingroup$ if the last paragraphs are quotes, could you put them in quoteblocks, and possibly provide the sources? $\endgroup$– FedericoNov 8, 2018 at 14:49
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$\begingroup$ I cannot disagree with any of the above, but I'm not sure it really addresses the question. There are a great many published non-precision VOR and NDB approaches that involve a timed procedure turn, followed by starting the clock when a fix is crossed, and executing a missed approach based on elapsed time. (for a given airspeed) Is this what the OP was asking? Because I can provide a more detailed answer... (but I'm not sure how to post pictures in an answer) $\endgroup$ Nov 8, 2018 at 17:29
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$\begingroup$ Actually, there is a perfect example of timing from the Final Approach Fix, (FAF) to the Missed Approach Point, (MAP) of 4.4 NM in the lower right corner of the ILS LOC rw 7 approach depicted above. Depending on the airspeed being flown the time to the MAP is shown on the second row. For aircraft without distance measuring equipment the pilot would rely on timing to know when the MAP was reached. I would be happy to post this as an answer, but I do not know how to add a picture, and don't want to refer to another answer in case it is later deleted. $\endgroup$ Nov 8, 2018 at 17:39
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$\begingroup$ @MichaelHall That's not the same thing as a timed approach $\endgroup$– TomMcWNov 8, 2018 at 20:02
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$\begingroup$ @TomMcW, it isn't obvious to me what the OP was asking. $\endgroup$ Nov 8, 2018 at 20:15