AVSIG: 30/90 degree intercept? wwswsigarch.jpg (7236 bytes)

✈ . . . . . . ✈ . . . . . ✈ . . . . ✈ . . . ✈ . . ✈ . ✈ . . ✈ . . . ✈ . . . . ✈ . . . . . ✈ . . . . . . Touch-and-Go to our Live Forum (This is a Read-only Archive of the 2004-2017 AVSIG Forum)


AVSIG Discussion Sections >> Air Traffic Control

Scott Dunham (RDU)
Top Gun


Reged: 04/29/04
Posts: 6470
Loc: Chapel Hill, NC
Re: 30/90 degree intercept?
      07/25/17 02:37 AM

Reading the TERPS manual late at night always makes my head hurt, but yes, at an IAF that works. DME arcs are a good analogy that might make you feel better about it - the intercept angle is 90 degrees if the DME transmitter is on or in line with the final approach course, but the DME source can also be offset from the FAC. If it's on the other side of the localizer from the aircraft, the intercept angle can actually be more than 90 degrees and still legal. Because of the distance from the runway and the wider localizer course further from the airport, the intercept angle is less critical than when you're vectoring closer to the FAF, hence the 20/30 degree limits approaching the FAF.

The key is that the intercept has to occur within obstacle protected airspace, and far enough out to give the crew a sporting chance to get laterally established and stable before the FAF. TERPS establishes minimum distances for the intermediate segment from the arc/LOC intercept to FAF to do that. In the 7110 example, the critical distance would be from SECND to the FAF, and at POC it would be LIZZE to HAWNN. The holding pattern template and protected trapezoid at LIZZE should cover the obstacle clearance at the turn, but I need to look a bit more to see what guarantees that the IF length is adequate to get stabilized in all non-DME cases.

Post Extras Print Post   Remind Me!     Notify Moderator


Entire topic
Subject Posted by Posted on
* 30/90 degree intercept? Stephen Loeffler (SoCal TRACON) 07/23/17 09:34 PM
. * * Re: 30/90 degree intercept? Scott Dunham (RDU)   07/25/17 02:37 AM
. * * Re: 30/90 degree intercept? Stephen Loeffler (SoCal TRACON)   07/25/17 03:36 PM
. * * Re: 30/90 degree intercept? Kcid LlirreM   07/27/17 08:35 AM
. * * Re: 30/90 degree intercept? B. Butler (Oregonian)   07/31/17 05:55 PM
. * * Re: 30/90 degree intercept? Stephen Loeffler (SoCal TRACON)   07/28/17 03:53 AM
. * * Re: 30/90 degree intercept? Scott Dunham (RDU)   07/30/17 10:32 AM
. * * Re: 30/90 degree intercept? Scott Dunham (RDU)   07/26/17 01:38 AM
. * * Re: 30/90 degree intercept? sreyoB yrraL   07/26/17 05:06 AM
. * * Re: 30/90 degree intercept? Stephen Loeffler (SoCal TRACON)   07/26/17 03:54 PM
. * * Re: 30/90 degree intercept? sreyoB yrraL   07/27/17 12:57 AM
. * * Re: 30/90 degree intercept? Stephen Loeffler (SoCal TRACON)   07/28/17 03:44 AM
. * * Re: 30/90 degree intercept? sreyoB yrraL   07/28/17 10:30 AM
. * * Re: 30/90 degree intercept? Scott Dunham (RDU)   07/26/17 12:44 PM
. * * Re: 30/90 degree intercept? Jeff Hartmann CIC   07/26/17 02:29 PM
. * * Re: 30/90 degree intercept? Stephen Loeffler (SoCal TRACON)   07/26/17 03:55 PM
. * * Re: 30/90 degree intercept? Jeff Hartmann CIC   07/27/17 02:08 AM
. * * Re: 30/90 degree intercept? sreyoB yrraL   07/25/17 10:10 AM
. * * Re: 30/90 degree intercept? Scott Dunham (RDU)   07/26/17 01:41 AM
. * * Re: 30/90 degree intercept? Todd Alfes   07/24/17 10:08 PM
. * * Re: 30/90 degree intercept? sreyoB yrraL   07/23/17 11:17 PM
. * * Re: 30/90 degree intercept? Todd Alfes   07/24/17 10:33 PM
. * * Re: 30/90 degree intercept? Stephen Loeffler (SoCal TRACON)   07/24/17 11:24 AM
. * * Re: 30/90 degree intercept? sreyoB yrraL   07/24/17 11:35 AM
. * * Re: 30/90 degree intercept? Stephen Loeffler (SoCal TRACON)   07/25/17 03:50 PM
. * * Re: 30/90 degree intercept? sreyoB yrraL   07/25/17 07:31 PM
. * * Re: 30/90 degree intercept? Stephen Loeffler (SoCal TRACON)   07/24/17 12:04 AM
. * * 30/90 degree intercept? Ray Tackett   07/23/17 10:02 PM

Extra information
0 registered and 5 anonymous users are browsing this forum.

Moderator:  Mike Overly 



Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled

Rating:
Thread views: 6629

Rate this thread

Jump to

Contact Us AVSIG

Powered by UBB.threads™ 6.5.5

Logout   Main Index    AVSIG Aviation Forum