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separation on ILS/PMR app.

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freighthumper

Well-known member
Joined
Aug 19, 2002
Posts
173
Can anyone tell me what the minimum lateral separation is to 2 aircraft on a simultaneous close parallel approach?
 
Ive been digging through the AIM looking for it, all I can find is there is a 2000' equidistant no transgression zone(NTZ) between the parallel approach courses, but this is for simultaneous parallel apps with RW CLs spaced 4300 apart or more. Simultaneous close parallel(PMR) ops are for apps with RW CLs less than 4300 apart, and all I can find for this is the the minimum 3 miles radar sep, and 1000 vertical sep during turn on to close parallel final app course.
 
PRM apchs

I see what you mean, they dont really give a specific distance per say, but does mention the NTZ as being a minimum of 2000' like you said. This distance plus the staggarded altitude of the 2 apchs of 1000', having the right training, equipment and the TCAS turned to TA only. Then the PRM controller can issue an breakout or changes as the situations requires.

I guess its a question for an ATC person, but it seems to me each approach would be a bit different.
Anyway here is where I found what I could about this, hope this helps...


2004 AIm Page 656

figure 5-4-15

Under air traffic procedures for parallel ILS/MLS appchs.

Hope this helps.

Link to on-line AIM just in case you dont have the 2004 book.

http://www.faa.gov/ATpubs/AIM/index.htm
 
Last edited:
I'm not exactly sure at what point are you looking for lateral seperation. If it being vectored onto the approach, then it is 3 mile lateral and 1000 feet vertical. Once on the final approach course the two aircraft can be seperated laterally by as little as 3000 feet.

ILS-PRM approaches are required when two runway centerlines are spaces less than 4300 feet apart, but never less than 3000 feet.

Also, aircraft with TCAS II capability leave it in RA mode at all times. This was a change from the original FAA requirement. All TCAS II equipt aircraft follow the ATC issued heading change and if there is a conflicting vertical guidance between the RA and ATC, follow the vertical guidance from the RA.

FAA ILS-PRM website
 
Big difference

What you said and what the notice says you referenced is greatly different that the 2004 AIM that I referenced above.

The Aim mentions that hey waht you to follow the PRM controller's breakout instructions because they can react quicker and more accurately than the TCAS which might interpret and provide incorrect instructions in the event of a problem,....

BUt I'm not working right now so I would not have the latest policy changes that you guys are working to today.

One other thing was the minimum lateral distance was said to be 2500' not 3000', maybe this is a change as well...
 

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