DME Hold entry

[A Squared]

Hey, look at the big brain on A Squared.

Heheheh, didn't do Brad much good, he still wound up dead <g>

 

[JRSLim]

Jules

Heheheh, didn't do Brad much good, he still wound up dead <g>

Say Hold again -- I dare ya, I double dare ya, Say hold one more time!

 

[A Squared]

Say Hold again -- I dare ya, I double dare ya, Say hold one more time!

W-what????

 

[100LL... Again!]

With a 4nm leg, you would want to modify your teardrop entry a little since flying a 30 degree offset for 4 miles might put you an awfully long way from the inbound course.

I would fly the 30 degree offset for about 45 sec to 1 minute, then parallel the inbound for the rest of the outbound leg.

 

[A Squared]

With a 4nm leg, you would want to modify your teardrop entry a little since flying a 30 degree offset for 4 miles might put you an awfully long way from the inbound course.

I would fly the 30 degree offset for about 45 sec to 1 minute, then parallel the inbound for the rest of the outbound leg.

Not necessarily. The templates which determine protected airspace for holding have enough width to provide protection for a teardrop entry as long as the holding leg, In fact the longer the holding leg, the "fatter" the airspace template is proportionally. you may wish to stay close to the inbound course as a mater of personal preference (I probably would also) but it is not required to remian in hte protected area.

 

[100LL... Again!]

That is essentially what I meant. The protected area is HUGE on such a hold, but 4nm on a 30 degree divergent course would require a pretty hefty intercept to regain the course (zero-wind).

If the wind was pushing you toward the course, you would find it slightly less of a problem. If the wind was drifting you away, you might end up with a long drive before recapturing the inbound course.

Since the sine of 30 degrees is .5, four miles of 30 degree offset would put you close to two miles away from the inbound.

By way of comparison, a 120 aircraft would travel 2nm in 1 min outbound, putting it 1 nm from the inbound, which is fairly close to the zero-wind turn diameter at that airspeed (no wind).

A 180 knot aircraft would travel 3nm, putting it 1.5 miles offset, again fairly close to the turn diameter at that speed (no-wind).

So, a really slow aircraft would end up close to two miles from the inbound, with a turn diameter of close to 1 nm, necessitating a decent intercept angle to regain the course (plus or minus wind, of course).

 

[JRSLim]

I think it is required

For the hold entry, there's no reason to go to the 4NM, but for the legs you need follow the chart. If the disance for the leg is specified, then that is the distance that is required - confirmed by AIM 5-3-7:

b. If the holding pattern is charted and the controller doesn't issue complete holding instructions, the pilot is expected to hold as depicted on the appropriate chart.


5 Distance Measuring Equipment (DME)/ GPS Along Track Distance (ATD)
...The controller or the instrument approach procedure chart will specify the length of the outbound leg. The end of the outbound leg is determined by the DME or ATD readout.


I can see where initially it seems the distance should be a limit not a specified requirement at least as far as obstacle clearance- if you are covered out to 4NM, then you should be safe at 2NM. However if ona GPS approach you made a short holding pattern and turned inbound within 2NM of the FAF, your unit would go active, possibly making things a bit tight. The Aim states when a Barb defines a procedure turn, the point at which the turn may be commenced and the type and rate of turn is left to the discretion of the pilot. However when a holding pattern replaces a procedure turn, the holding pattern must be followed - same with a teardrop. If it shows a mileage or a time, that is part of the procedure.

'The Jepp plate only shows 4nm in the profile view', but is still shows it.

 

[100LL... Again!]

I'll take a look at an NOS chart.

Sometimes Jep uses their own version of the terminology that means the same thing, but can appear to mean something else.

I can't remember where I saw that before, but comparing NOS to JEP is interesting when it comes to the more unusual elements of approaches, such as this 4nm hold, which is not especially common.

 

[A Squared]

However if ona GPS approach you made a short holding pattern and turned inbound within 2NM of the FAF, your unit would go active, possibly making things a bit tight.

You'll notice that the hold is located at an intermediate point, 5 nm from the FAF, not at the FAF. Furthermore, you can fly the procedure with no procedure turn from one of the IAF's located on either side if the hold This requires a 90 degree turn onto the intermediate course which gives you leess than 5 nm (after a 90 degree turn) to get established before the FAF, which is obviously deemed adeqate, but you're saying that intercepting the inbound course 2 nm *further out* (ie: 7NM to get established) would not be adequate? Doesn't make sense.

 

[JRSLim]

You'll notice that the hold is located at an intermediate point, 5 nm from the FAF, not at the FAF. Furthermore, you can fly the procedure with no procedure turn from one of the IAF's located on either side if the hold This requires a 90 degree turn onto the intermediate course which gives you leess than 5 nm (after a 90 degree turn) to get established before the FAF, which is obviously deemed adeqate, but you're saying that intercepting the inbound course 2 nm *further out* (ie: 7NM to get established) would not be adequate? Doesn't make sense.

Er, uhmm ahh, nevermind.
Guess THAT part of my reply doesn't apply. Got so caught up in the excitement I didn't take a real close look at the chart.
Guess I don't have to worry about Jules bustinig a cap in my face.

 

[A Squared]

Guess I don't have to worry about Jules bustinig a cap in my face.

LOL!

 

[HMR]

I can see where initially it seems the distance should be a limit not a specified requirement at least as far as obstacle clearance- if you are covered out to 4NM, then you should be safe at 2NM. However if ona GPS approach you made a short holding pattern and turned inbound within 2NM of the FAF, your unit would go active, possibly making things a bit tight. The Aim states when a Barb defines a procedure turn, the point at which the turn may be commenced and the type and rate of turn is left to the discretion of the pilot. However when a holding pattern replaces a procedure turn, the holding pattern must be followed - same with a teardrop. If it shows a mileage or a time, that is part of the procedure.

'The Jepp plate only shows 4nm in the profile view', but is still shows it.

Good post. BUT, even if the hold was at the FAF, I still don't agree with your procedure. As I said before, the profile view on the Jep shows 4nm the same way it shows 10nm on most other approaches. Using your logic, would you fly 10nm legs because it's in the profile view?

It sounds like you're not using your GPS properly. If you're going to hold, the GPS should be in "OBS"(or equivalent) mode. This will prevent your GPS from going active within 2nm and also prevent auto-sequence eveytime you cross the fix while holding. If you're doing one turn for the PT, you WANT the GPS to go active so that you have .3nm sensitivity for intercepting and flying the approach.

 

[JRSLim]

From the way I read it, if there is a published time or distance, then that is the requirement that must be adheared to, and not just a limit or suggestion.
I mostly use the Garmin 430, and while I feel I am pretty good with it, I admit I have never done a hold to a GPS apporach with it. I was thinking that you would use OBS for the hold, but the manual states that the unit automatically goes into suspend when entering the hold, and then cancells that to return to auto sequensing when inbound-- which means if you have more than one circuit, yo would have to hit OBS. I will have to make a point to practice that.
Thanks for the input. The plus side about having your head up you a** as far as I do sometimes, is that I don't have to use foggles for practice apporoaches!

 

[Tinstaafl]

Can't answer for TERPS, but ICAO's PANS-OPS imposes another limitation for sector 2/teardrop entries.

The outbound of a sector 2/teardrop entry is a 30 deg reciprocal offset from the holding pattern inbound track for no longer than the outbound time of the holding pattern *with a catch*: The outbound time of the entry is not to be greater than 1 min 30 sec even if the holding pattern has a greater duration timing. If timing for more than 1:30 on the sector 2 entry then the period after 1:30 is to be flown parallel to the holding pattern outbound heading ( +/- any wind allowance).

 

[integrale]

This is from one of my USAF advanced insturment school materials.
"ATC expects pilots to fly the complete holding pattern as published. Therefore, do not shorten the holding pattern without clearance from ATC."