Primary and Secondary Runway Ends

[scruffyduck]

Working on ADE has caused me to realize that I don't understand how the Primary and Secondary runway ends are defined. Does it relate to the heading given for the runway? Or is the lower number end always the primary (I don't think so). Is it therefore possible to have any number and therfore heading as the primary end?

Dunno why I have never sorted this out in my mind before but it has been triggered by trying to get the offset threshold and overruns placed at the correct end of the runway.

 

[rfields]

The primary end of the runway is the one which matches the true heading of the runway properties - yes I know runway designator numbers match the magentic heading - but the runway position matches the true heading.

In the vast majority of FS airports this is the lower of the two designators.

Even an airport like PAKT which has a true heading of 207.050 in FS2004 - mag 181.1 - is listed as Rwy 18 as the primary end and Rwy 36 as the secondary end.

This is the key:

<Runway number="18" designator="NONE"
lat="N62 19.23075"
lon="W150 5.62116"
alt="109.12M"
length="1063.75M"
width="22.86M"
heading="207.05"

That is the primary. Notice there is no property or place in FS except for an approach code or start spot for Rwy 36. It is defined as the secondary of Rwy 18. Rwy 36 has no properties.

You can reverse the headings and designators making Rwy 36 the primary - however, you can also play havoc with navaids especially loalizers if you are not very careful.

The runway property would need to have a heading of 27.05 to make Rwy 36 the primary.

 

[scruffyduck]

Thanks Reggie. That is a big help

 

[DougMatthews]

Working on ADE has caused me to realize that I don't understand how the Primary and Secondary runway ends are defined. Does it relate to the heading given for the runway? Or is the lower number end always the primary (I don't think so). Is it therefore possible to have any number and therfore heading as the primary end?

Dunno why I have never sorted this out in my mind before but it has been triggered by trying to get the offset threshold and overruns placed at the correct end of the runway.

The lower number is always the primary EXCEPT when there is no start at the low number end AND there is a start at the high number end.

Reggie's post is the downstream result of this.

There are 18 instances of this in FSX:

ICAO,NUMS
3AK,07/25
3MO,18/36
8U4,14/32
EDDF,18/36
EDGT,11/29
EDRS,04/22
I97D,1/19
I98D,9/27
KCHQ,18/36
LFLJ,05/23
LSZY,07/25
LYVR,16/34
MYZ3,07/25
S90,14/32
SUME,16/34
SVMP,08/26
U60,01/19
UNBB,06L/24R

-Doug

 

[scruffyduck]

Thanks Doug

 

[jvile]

Jon

What Doug's list is also saying are those runways are oneway. When the Start Location is deleted from a runway such as the Primary end in FS the runway property record must also say

primaryTakeoff="FALSE"
primaryLanding="FALSE"

I was going to bring this up in a future post when ADE is further along. If some one trys and change a Takeoff or Landing from TRUE to FALSE then a total of 3 records must be changed or some kind of warning issued.

The FALSE may not be honored if that end of the runway also has a ILS or non-precision record in the approach data. It can get confusing.

 

[DougMatthews]

Jon

What Doug's list is also saying are those runways are oneway. When the Start Location is deleted from a runway such as the Primary end in FS the runway property record must also say

primaryTakeoff="FALSE"
primaryLanding="FALSE"

I was going to bring this up in a future post when ADE is further along. If some one trys and change a Takeoff or Landing from TRUE to FALSE then a total of 3 records must be changed or some kind of warning issued.

The FALSE may not be honored if that end of the runway also has a ILS or non-precision record in the approach data. It can get confusing.

Affirmative. The runway data we get from Jeppesen is the individual (i.e. 18 - one way) runway. We have to pair them up (i.e. 18/36). In these cases we only get one end.

-Doug