Intercepting the localizer at IAD
09-27-2013, 01:56 PM
#1
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Intercepting the localizer at IAD
The other day I was flying into iad and told to intercept the localizer close to 30 miles out. I don't fly into there that often. I simply cleaned up the fms, and intercepted in white needles. I figured that intercepting in green would have caused the autopilot to constantly turn back and forth chasing the localizer because we were so far out. My captain told me that technically we have to be in green needles in order to be legal because our instructions were "intercept the localizer." Anyone have any thoughts on the best way to do this next time it comes up with a fed on board?
09-27-2013, 03:38 PM
#2
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Originally Posted by Taildragger86
The other day I was flying into iad and told to intercept the localizer close to 30 miles out. I don't fly into there that often. I simply cleaned up the fms, and intercepted in white needles. I figured that intercepting in green would have caused the autopilot to constantly turn back and forth chasing the localizer because we were so far out. My captain told me that technically we have to be in green needles in order to be legal because our instructions were "intercept the localizer." Anyone have any thoughts on the best way to do this next time it comes up with a fed on board?
09-27-2013, 03:56 PM
#3
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Joined APC: Oct 2012
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It is perfectly legal. If cleared for an instrument approach simply switch to green needles (localizer) when within the localizer service limits. You could even back FMS data up with the localizer in blue needles too. Much more on this, but what you did is appropriate. If not on the visual, definitely go "green" before the FAF.
09-27-2013, 04:29 PM
#6
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Originally Posted by Cubdriver
What's a typical localizer service limit USMC? 20 miles?
Originally Posted by cfibrad
The short answer is 18 NM from the antenna, ref AIM chapter 1.
As soon as taildragger tells me which runway I will look it up and post it.
ESV's can be extensive if situations are right and there is a need for procedural control out to such a distance. I did a 40 nm localizer approach some time ago at KIAH.
09-27-2013, 04:35 PM
#9
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I've heard that argument at FedEx, too. It makes no sense.
If your aircraft intercepts the LOC, then who cares how it got there. What if you're hand-flying with the flight director off?
Arming NAV, white needles or any other mode and using that to intercept the LOC is transparent to ATC, as long as you end up with the raw data LOC display centered.
Obviously if you were going to have the autopilot track it and intercept G/S, you'll eventually need to enter a mode that actually tracks the ILS.
But, for long distance intercepts of the LOC where signal strength may be low, I don't see the problem.
If your aircraft intercepts the LOC, then who cares how it got there. What if you're hand-flying with the flight director off?
Arming NAV, white needles or any other mode and using that to intercept the LOC is transparent to ATC, as long as you end up with the raw data LOC display centered.
Obviously if you were going to have the autopilot track it and intercept G/S, you'll eventually need to enter a mode that actually tracks the ILS.
But, for long distance intercepts of the LOC where signal strength may be low, I don't see the problem.
09-27-2013, 04:37 PM
#10
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Originally Posted by captain152
30nm is a helluva long way out to intercept a LOC. Is it legal? Sure, but it's probably gonna bounce around a bit until you get to 20-25 out.
40?! Holy balls! I hope you're VFR
40?! Holy balls! I hope you're VFR
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