Help with new approach

[Lance F]

http://204.108.4.16/d-tpp/0812/00983ILD27.PDF
ILS27 at KAHN has been a good practice approach and good alternate when the weather turned bad around here for a long time. It never changed.
However, with the new Nov 20 issue there are substantial changes; a couple of which I'm not sure about.
1. There is an arrow coming off the AHN VORTEC labeled "2500 to BLLDG 087deg (5.3)" . Is it a transition route?
2. What is the purpose of the intermediate fix IMAVE?

The published missed approach hold used to be at the NDB BJT, which was very convenient for practice. Now it's 23.6 miles away at VESTO,

Thanks!

 

[bbchien]

It's a pretty good bet they're about to decommission BJT, which serves no other purpose that to support the NDB apporach to 27. I thought initially that something had happened to the radar coverage.

I can only speculate why IMAVE is there- maybe it's a radar fix.

 

[KennyFlys]

I flew this rascal a few dozen times during IR training. It has changed a bit.

1. There is an arrow coming off the AHN VORTEC labeled "2500 to BLLDG 087deg (5.3)" . Is it a transition route?

The plate I have from my Jawjuh days doesn't show a tower. The new plate has a tower at 919 feet en route between the VORTAC and Bulldog; approximately one mile west of Bulldog. It appears they want you back at 2500 MSL before you cross the VORTAC outbound to insure you're sufficiently higher than the tower.

The hold instructions changed to show that as well. Previously, it was simply a left turn to 2500.

2. What is the purpose of the intermediate fix IMAVE?

VESTO is an IAF requiring no PT before joining the localizer at CEKUV. IMAVE becomes an intermediate fix on the localizer intercepting with R-088 AHN.

It shows 2500 to IMAVE but that still doesn't change to lower until Bulldog. So, I'm thinking they want you no less than 2500 for the entire course, not just crossing Bulldog at 2500. It apears that may be more for traffic departing the hold for the approach. I'm still a bit confused on that one as I'd never go below the altitude established for the entry or as directed; whichever is higher.

The published missed approach hold used to be at the NDB BJT, which was very convenient for practice. Now it's 23.6 miles away at VESTO,

That's probably due to the tower now located ahead of Bulldog. The tower is only about a mile west of Bulldog so that presents too much opportunity to overshoot the fix as well as be off on altitude during the hold.

They take you out to VESTO where there isn't much chance of hitting anything but a bird. The other side of it is Athens is getting more and more busy so they may want holding traffic well away from the approach course.

The holds around KAUS takes you out to the boonies much like this one.

 

[TangoWhiskey]

"2500 to BLLDG 271° (6.2)" is not a transition route (bold line, not thin: you're already on the approach course by the time you get here) but it does mark the altitude, heading, and distance between IMAVE IF and BLLDG if you're flying the approach using VESTO as the IAF.

Another comment: While you can identify IMAVE as 11.5 DME from AHN, I'm kind of surprised that the also note it as being with the AHN R-088 centers. That's a very acute angle to be using it to identify a fix. Since DME is required per the title, why would they even note the AHN R-088 at IMAVE?

 

[TMetzinger]

Maybe for rho/theta RNAV systems?

 

[ghogue]

"2500 to BLLDG 271° (6.2)" is not a transition route (bold line, not thin: you're already on the approach course by the time you get here) but it does mark the altitude, heading, and distance between IMAVE IF and BLLDG if you're flying the approach using VESTO as the IAF.

It is a transition from the enroute structure, AHN VOR, to the IAF BLLDG, the fix at which you would begin the Procedure Turn.

edit. Okay, I see. You were referring to the info on the Intermediate segment from IMAVE to BLLDG. I didn't catch the specific info you posted and thought you were referring to the Transition from AHN to BLLDG as the OP had asked about.

 

[TangoWhiskey]

It is a transition from the enroute structure, AHN VOR, to the IAF BLLDG, the fix at which you would begin the Procedure Turn.

You're correct. I was commenting on the "271 (6.2)" note, and Lance asked about the "087 (5.3)" note.

 

[ghogue]

You're correct. I was commenting on the "271 (6.2)" note, and Lance asked about the "087 (5.3)" note.

I just posted an edit above, about that at the same time as your post.

 

[poadeleted20]

1. There is an arrow coming off the AHN VORTEC labeled "2500 to BLLDG 087deg (5.3)" . Is it a transition route?

Yes (and it is a thin line). AHN is an enroute feeder and BLLDG is the IAF. This allows the approach to be flown from AHN without making AHN an IAF.

2. What is the purpose of the intermediate fix IMAVE?

One thing it does is allow GPS-equipped aircraft to be cleared direct to IMAVE without giving them vectors to final or running them out to VESTO. There is an exception to the "must go through an IAF" rule which allows GPS-equipped aircraft to be cleared direct to an IF as long as they will not have to make more than a 90-degree turn to join the approach.

The published missed approach hold used to be at the NDB BJT, which was very convenient for practice. Now it's 23.6 miles away at VESTO,

It does indeed look like they're getting ready to decommission the BJT NDB -- they just did that with the Colbe LOM here at Salisbury.

 

[Lance F]

One thing it does is allow GPS-equipped aircraft to be cleared direct to IMAVE without giving them vectors to final or running them out to VESTO. There is an exception to the "must go through an IAF" rule which allows GPS-equipped aircraft to be cleared direct to an IF as long as they will not have to make more than a 90-degree turn to join the approach.

That I didn't know. Thanks, Ron. I wonder if you could request direct to the IF rather than vectors to final? That could be a time saver if ATC would do it.

 

[poadeleted20]

That I didn't know. Thanks, Ron. I wonder if you could request direct to the IF rather than vectors to final? That could be a time saver if ATC would do it.

I'm not sure it would be a time-saver if VTF is possible (with VTF you'd intercept further in), but you can certainly ask if VTF is not available.

 

[Lance F]

I'm not sure that there is a way to set up an approach to an IF on the GPS either, at least in a 430.

 

[TangoWhiskey]

I'm not sure that there is a way to set up an approach to an IF on the GPS either, at least in a 430.

Could you not load the approach with BLLDG as the IAF, then insert IMAVE as the previous waypoint before BLLDG, then go direct IMAVE? Activate the approach as soon as you pass IMAVE. You're still far enough outside BLLDG for it to scale down / go active for the approach.

 

[flyingcheesehead]

I'm not sure that there is a way to set up an approach to an IF on the GPS either, at least in a 430.

Could you not load the approach with BLLDG as the IAF, then insert IMAVE as the previous waypoint before BLLDG, then go direct IMAVE? Activate the approach as soon as you pass IMAVE. You're still far enough outside BLLDG for it to scale down / go active for the approach.

No, this is way easier than that on the 430.

When you choose the approach and it asks you where to start the approach, choose VESTO. Activate the approach, push FPL to bring up the flight plan, push the big knob for cursor mode, twist the large outer part of the knob until IMAVE is highlighted, then press direct, enter, enter. Done.

 

[gismo]

No, this is way easier than that on the 430.

When you choose the approach and it asks you where to start the approach, choose VESTO. Activate the approach, push FPL to bring up the flight plan, push the big knob for cursor mode, twist the large outer part of the knob until IMAVE is highlighted, then press direct, enter, enter. Done.

I'd do one more thing if you're on autopilot at the time. And that's to put the AP into heading mode after centering the heading bug on your current course. Once you have the direct to IF programmed switch back to GPS guidance. I've found that it's generally a good idea to do this whenever making flight plan chances that go beyond picking a waypoint out of the existing plan for a direct-to shortcut, especially if you want to avoid unwanted heading changes and/or rapid changes in bank angle.

 

[John Collins]

That I didn't know. Thanks, Ron. I wonder if you could request direct to the IF rather than vectors to final? That could be a time saver if ATC would do it.

Yes (and it is a thin line). AHN is an enroute feeder and BLLDG is the IAF. This allows the approach to be flown from AHN without making AHN an IAF.
One thing it does is allow GPS-equipped aircraft to be cleared direct to IMAVE without giving them vectors to final or running them out to VESTO. There is an exception to the "must go through an IAF" rule which allows GPS-equipped aircraft to be cleared direct to an IF as long as they will not have to make more than a 90-degree turn to join the approach.
It does indeed look like they're getting ready to decommission the BJT NDB -- they just did that with the Colbe LOM here at Salisbury.

The controller can only use the direct to an IF if the approach is a GPS or RNAV, not an ILS. There are 5 other requirements for use of this type of clearance to a GPS or RNAV IF: radar monitoring required, aircraft filed with advanced RNAV equipment code (/G), pilot is to be advised to expect the direct to the IF at least 5 NM in advance, an altitude is assigned to the IF, and intercept can not be more than 90 degrees and altitude permits normal descent to FAF.

 

[wsuffa]

Interesting the requirement for simultaneous reception of the DME and the LOC, too.....

 

[Lance F]

The controller can only use the direct to an IF if the approach is a GPS or RNAV, not an ILS.

Then I am still wondering why there is an IF shown on this approach. For what or whose purpose?