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?

What runway at KIAD?

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.

What's a typical localizer service limit USMC? 20 miles?

The short answer is 18 NM from the antenna, ref AIM chapter 1.

cfibrad is correct - in the US - without an ESV.
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.

In ORD, they'll ask you to join 40 out.

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

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.

They meet the same tolerances as they do once they get inside the 18nm SSV. Some localizers bounce around in pretty close. The first time I flew the ILS to 31L at KDAl I thought I was on the ski slopes doing the Giant Slolam! (but it too was within tolerance - but I wonder how a pilot feels the first time going into KDAL IMC and the A/P seems to be chasing its' tail. But then come to think about it - what do you expect with signals bouncing off the downtown skyscrapers?

Nope....#7 in line behind Royal Jordanian.

IAH is my personal best...62 miles out in the middle of the night. I backed it up with the GPS of course, but it was pretty much on the GPS course and relatively steady the whole way in. Guess that'll happen with a lot of flat land - but I was impressed the transmitter was even that strong.

It was runway 1R

As I recall, the LAX 25L localizer was one example of this. You would be cleared to intercept it a long way out, but not to follow the GS until FUELR intersection.

Interesting find Taildragger.
LOC IAD does not have an ESV associated with the facility except for the DME. The DME ESV is out to 19nm between 3,000 and 4,800'
According to this information it would not be correct for ATC to instruct you to intercept the LOC outside of the standard 18nm service volume. I'll have to ask one of the ATC'ers that I work with about it more on Monday or maybe a controller with local knowledge on the forum will provide some input.

LOC LAX is an example of a LOC that has numerous ESVs associated with the facility. The LOC has an ESV all the way out 85nm from 10,000-15,000'! There is another LOC and DME ESV at 42nm between those same altitudes and you'll see from the approach plate that procedurally they want to use LUVYN at no lower than 10,000' at 41DME off of the LOC. The GS also has an ESV that would encompass FUELR, though it shows it only at 8100 and it looks like the plate reads that you could be at 7,000 or above.

ESV? Extended service volume?

I can now pick-up DFW's loc's 90+ miles away! From over cotton pick'n FSM!!!

ATC w/radar can practically ignore NAVAID service volumes (FAAH 7110.65, chapter 4, sec. 1).

Not true. See below

Yes. ATC can direct an intercept outside of SV, but they remain responsible for monitoring position (and making deviation notifications) until within SV. 4-1-2, note 3. (Pg 184).

Yes - I saw the note and looked at the reference.
Tomorrow I'll be asking some of the ATC'ers that I work with to explain this to me further. It sounds more like ATC using radar to guide the aircraft onto a 'fictitious' LOC course. From my perspective - if that LOC signal has not been checked out there it can 't be used - period. If TERPS sent a procedure to me with a LOC fix out at 40nm and there was no ESV request attached - it would be rejected and returned for redesign or request the appropriate ESV - and IF it passed then we would give it to them.

The current SV limits are standards that were written in a different era of technology. Everyday, thousands of airplanes at hundreds of airports are joining localizers outside of 18 miles, and they're all tracking quite reliably.

This is what the Air Force taught us:
I'm trying to find the equivalent statement in the FAA regulations. I'm sure it's in there, because most of the stuff in 11-217 comes from CFRs, AIM, etc.

No....much of the technology is still the same and even with the newer loc antennas or GS antenna - the SVs remain the same. Yes....100s of aircraft may be intercepting locs outside 18nm. MANY locs have ESVs outside of 18nm. You, as a pilot or controller, might very well not know if a loc, (or any other ground based NAVAID) has an ESV. One clue on the chart would be any point located outside of SSVs with DME provided from the facility - as was the case with the example of LAX Rwy 25s from earlier in the thread.

Sluggo -
In the first bolded case - there would be an ESV if the procedure depicts a fix outside of the SV. Until I ask my co-workers for further clarification, I'll state again that in a case such as EasternATC or the OP may be describing, **technically** the aircraft would be under radar control outside of the SV while "intercepting and tracking the localizer", because **technically**, without an ESV, the localizer signal does not exist outside of the SV and signal strength and quality of the signal in space can not be guaranteed to meets minimum tolerences.

This is nothing new. It's been in 7110.65 and practiced by ATC for at least 20 years now. I was an AF instrument instructor and we always covered this during the required annual IRC (Instrument Refresher Course)....


Sluggo: 7110.65, pg 184, 4-1-2 note 3

I've asked two and got different answers.
I think the one with some ATC experience from a LONG time ago might not have the most *recent* answer, so I've asked the co-worker with recent ATC experience to contribute to the thread. He agrees with EasternATC and nfn, but has some additional explanation to pass on that I hope will add to the conversation too. Hopefully we'll see him on someday today so check back for the latest updates!

or you could legally be in white that far out, with your blue needle preview as the backup. Or pilot flying in white and pnf in green as a backup.

We used to handle it like this....Green needles up for verification and HDG mode for AP. the LOC may swing back and forth but you can tweak the heading to keep you on the LOC course until you get solid reception on the LOC……that way AP doesn’t chase the swinging LOC.

Get'er done :D

Enjoy the Ride
 

Don't worry about the Fed on the jumpseat. If Approach cleared you to intercept and assuming cleared you for the approach, arm the APP mode and enjoy the ride.

Ferrying a 767 into ORD once from SEA, we were 20 miles outside of SEXXY for 14R and the approach controller told us "to turn right to a heading of 120, maintain 4,000' until SEXXY, cleared for the visual to 14R, cleared to land and cleared to the ramp. Goodnight". It was 3:00 AM and that was the last transmission we heard until the engines were shut down. As for the autoflight, we left it on just for the heck of it and it did a beautiful job once the APP mode was armed.

Not a big deal and the Marine answered your technical questions.

G'Night Mates:)

There was a very tragic and infamous crash of an airliner decades ago that was cleared, late at night, not by the approach controller, but by an enroute controller for an instrument approach some 40 miles from the airport.

It is why the NASA aviation reporting system, in part, exists today.

Why the splitting of hairs on this. Depending on your aircraft equipment and/or ops specs it is perfectly legal to use the fms in lieu of the localizer until you reach the FAF. Especially, if you are told to intercept LOC 20+ miles out. The guy that had the captain who demanded actual localizer capture was not correct, but since he was captain....

At my former airline, the FOM spelled out the procedure for this. We were to intercept the localizer via FMS needles until 18NM at which point we were to switch to the ground based localizer.

Go green, track the course and if the signal "strays" you off course it will be ATC's job to monitor that.

It seems that unless the critical area is protected as in the other A/C holding short of the CATII line, I always get a variance ride with the LOC in IAD as well as many others. My suggestions arm NAV and hand fly it..

+1, 31L at DAL is all over the place

Disregard. Wrong thread.