Tech Question for the experienced!

[Justino]

Hey all I know this is not a regional question but I have trusted your info before so here it goes:

Can I "legally" use a vor cross radial, not a approach transition route, to ident a FAF on a LOC course?

I have called AOPA and they had no clue. I can't find it anywhere. Is it a legal substitute for a radar fix (triangle depiction) on the Jepp plates (see MKE Loc 25L)


Thanks

Justino

ps. interview prep !

 

[tittyjet]

I have no idea...fly glass and these problems will be history.

Ask chperplt -- he knows these things.

 

[Rogue5]

It has been a LONG time since I could quote chapter and verse of the FAR/AIM, but I brushed a few cobwebs out of my brain and remembered this reference in the AIM:

1-1-9. Instrument Landing System (ILS)

a. General

1. The ILS is designed to provide an approach path for exact alignment and descent of an aircraft on final approach to a runway.

2. The ground equipment consists of two highly directional transmitting systems and, along the approach, three (or fewer) marker beacons. The directional transmitters are known as the localizer and glide slope transmitters.

3. The system may be divided functionally into three parts:

(a) Guidance information: localizer, glide slope;

(b) Range information: marker beacon, DME; and

(c) Visual information: approach lights, touchdown and centerline lights, runway lights.

4. Precision radar, or compass locators located at the Outer Marker (OM) or Middle Marker (MM), may be substituted for marker beacons. DME, when specified in the procedure, may be substituted for the OM.

5. Where a complete ILS system is installed on each end of a runway; (i.e., the approach end of Runway 4 and the approach end of Runway 22) the ILS systems are not in service simultaneously.


I believe this applies to the question you ask, and that would lead me to say no. Those fixes need to be ID'd very precisely, and a cross radial will not cut it. Thats the way I understood it.

 

[tittyjet]

rogue5:

If all of that was quoted from memory, you really need to get out more. Fish, find a girlfriend, softball, titty bar, bank robbery, knitting, visiting shut-ins .... ANYTHING!!

 

[Justino]

Thanks ! I thought so also! A cross radial is depicted going through the fix for what purpose then? One of those unknowns... again.

Thank you all for your help

Justino

Ps. I am trying to go glass cause I am sick of flying steam.

 

[Rogue5]

I know, I know... I need help.

BTW, I could remember that quote existed, but it was the trusty girlfriend who told me which section of the AIM it was in (she's be an F.O. for less time, and therefore still remembers the CFI stuff better).

 

[Wasted]

But the original question was with regard to a non-precision approach, not a precision approach....I don't see why you can't use cross radials on a non-precision (ie LOC 25L at KMKE) approach.

 

[TonyC]

Hey all I know this is not a regional question but I have trusted your info before so here it goes:

Can I "legally" use a vor cross radial, not a approach transition route, to ident a FAF on a LOC course?

I have called AOPA and they had no clue. I can't find it anywhere. Is it a legal substitute for a radar fix (triangle depiction) on the Jepp plates (see MKE Loc 25L)


Thanks

Justino

ps. interview prep !

It's not often that I have my Jepps sitting next to me, but since I do, here goes:


JEPPESEN Introduction Page 105, APPROACH CHART LEGEND APPROACH PLAN VIEW:

Right hand column, about halfway down, in reference to the point called TOWER: "The STO R-275* has a small arrowhead and is a cross radial forming Tower." On the previous page, right column, 2/3 down is the text "VOR cross radials and NDB bearings forming a position fix are 'from' a VOR and 'to' an NDB."


The triangle you see on the MKE LOC Rwy 25L is a Non-Compulsory Airspace Fix (Ref. INTRO page 105, upper left hand corner). Under the 2nd diagram on Jepps INTRO pg. 105 is the text, "Allowable substitutions for identifying a fix are noted in the planview." The IAF FAHEY can be defined three ways:

1. On the Localizer at 6.8 DME on the ILS IPXY DME
2. At the intersection of the Localizer and the HRK 010 Radial
3. By Radar

Radar is an OPTIONAL way of defining the fix. Notice that RADAR is not even required to fly the approach. (DME is not required to fly the approach, either. What you DO need is DME or another VOR receiver for the HRK 010 Radial or Radar to define FAHEY.) The Triangle doesn't mean RADAR FIX, and the words "RADAR FIX" shouldn't confuse the issue. The triangle is simply a Non-Compulsory Fix, and there are multiple ways to find it.


By the way, BAE also has an arrow (109 Radial) pointing at FAHEY, but it has a LARGE arrowhead - - it is an approach transition. It does NOT define FAHEY. If it defined FAHEY, it would also have a SMALL arrowhead (that's right, 2 arrowheads).

 

[Justino]

Wow, well thank you I followed your instructions and saw your point! That 4 sure clears the issue up. Thank you so much Tony.

Now back to more studying....

Justino