View Full Version : Definitive Airfield / Airstrip Location Point
Martinburney
2nd May 2003, 18:10
Hi all
It has always been a bone of contention, exactly where the reading
for a grid or Lat/Long reference is, for an Airfield/ Airstrip.
Surely by now, a definitive location should be qualified.
My suggestion is that, it should be at the centre of the runway, or
main runway, if there is more than one.
Your opinion is appreciated.
Regards Martin
matspart3
2nd May 2003, 18:14
For a Licensed aerodrome, it's the Aerodrome Reference Point...there is a definition of that in CAP168...but I think it often coincides with the midpoint of the longest runway, as per the centre of the ATZ
Mike Cross
2nd May 2003, 20:42
The definition is in Annex 14 of the International Convention on Civil Aviation (Commonly known as ICAO Annex 14).
While I can help on Annex 15 I don't have a copy of Annex 14, perhaps someone with access to one could post the answer.
Mike
Whipping Boy's SATCO
2nd May 2003, 21:54
It's something along the lines of:
"For a RW aerodrome the ARP is the geographical centre of the Main Instrument RW.
For non-runway aerodromes (grass fields) the ARP is the centre of the notified landing area."
I will scour my Annex 14 when I get back to on on Tuesday.
vintage ATCO
3rd May 2003, 00:31
Not a lot in Annex 14, viz
2.2 Aerodrome Reference Point
2.2.1 An aerodrome reference point shall be established for an aerodrome.
2.2.2 The aerodrome reference point shall be located near the initial or planned geometric centre of an aerodrome and shall normally remain where first established.
2.2.3 The position of the aerodrome reference point shall be measured and be reported to the aeronautical information services authority in degrees, minutes and seconds.
CAP168 defines the ARP as the geographical centre of the aerodrome and the centre of its traffic zone where an ATZ is established. This is normally taken to be the centre of the longest instrument runway.
VA
bletchleytugie
3rd May 2003, 00:34
Annex 14 Chapter 2 Aerodrome Date
2.2 Aerodrome Reference Point
2.2.1 An aerodrome reference point shall be established for an aerodorme.
2.2.2 The ARP shall be located near the intial or planned geometric centre of the aerodrome and shall normally remain where first established.
2.2.3 The position of the ARP shall be measured and reported to AIS in degrees, minutes and seconds.
Thats what my copy has to say on the subject.
Vintage atco must have got in on the act whilst I was composing my initial response!!
Vintage atco must have got in on the act whilst I was composing my initial response!!
StrateandLevel
4th May 2003, 01:47
"It has always been a bone of contention, exactly where the reading for a grid or Lat/Long reference is, for an Airfield/ Airstrip."
Does it really matter? If you are flying VFR you can see it out of the window. If you are flying a precision approach it will guide you to the runway. If you need a position to feed into the INS then a chart of airfield locations will tell you.
Is this another GPS users obsession?
It is indeed as my learned ATCO friends have said. No contention there.
Where it gets interesting is with older airfields that have changed "shape" over time, and hence the ARP has "moved". I had lots of fun with these when compiling the A4A airfields list! In the end, I decided that two ARPs less than 500m apart were probably the same place.
Similar with ex-RAF fields that have been returned to agriculture etc but where microlighting etc takes place on one part of the former field.
I have a suspicion that the RAF etc during WW2 may have been a bit less precise about how they defined the ARP - perhaps the CO's office?