Separation in a non-radar approach environment

[Sky Conductor]

Hi

I'm looking for information regarding procedural separation in a non-radar approach environment. I'm aware of all the various methods described in Doc 4444 and Mats Part 1. What i'm really interested in is Geographical separation or "deemed separation". As these are different for each airfield and are only available in Mats part 2 i believe. Interested in responses from all countries. What is allowed at your unit? Anyone any experience in methods used to separate departures against an arrival who will fly a dme arc leading to final approach?

PM me if you wish

Thanks

SC

[Spitoon]

In my experience geographic separation is usually used for flights operating visually and can be really useful for handling Special VFR flights - clearance such as one aircraft holding to the E of one point and another to the W of another point can be used to ensure the aircraft are never closer than the distance between the two points (I hope I don't need to draw a picture to show the relative positions of the points and aircraft!).

Deemed separation can be used for both visual and instrument flights and is applied when there is no suitable (or convenient) separation in Doc 4444 but the relevant authority is content that either there's no possibility that the aeroplanes will bang into each other or it satisfies some legal nicety (c.f. aircraft inside CAS are deemed separated from those outside CAS).

Certainly used this way in the past in the UK and I've seen similar principles applied elsewhere.

[Chilli Monster]

Anyone any experience in methods used to separate departures against an arrival who will fly a dme arc leading to final approach?

Yes.

Basrah Airport, in the south of Iraq. We have a waypoint (WOGET) which is the IAF for a DME arc leading to both the ILS 32 and VOR approach 14. The waypoint is 15 DME from the VOR (which is on the Airport) at 90 degrees to the runway axis. There is a hold associated with the waypoint.

Traffic departing 14 or 32 is deemed separated from traffic either holding at WOGET or inbound to the same runway as the departure, established on the arc, PROVIDED the departure flies runway heading until vertical separation is achieved.

Hope this helps

[Sky Conductor]

Thanks Spitoon. Yes we use the one east/one west all the time for Special VFR's

Yes Chilli that is exactly what i'm looking for. Check PM.

Doc 4444 (ICAO - Air Traffic Management) 5.4.1.2.1.2.1 states:
When aircraft are operating on tracks which are separated by considerbly more than the foregoing minimum figures, States may reduce the distance at which lateral separation is achieved.

I know they are dont come under ICAO but I believe in the US that NDB separation is right down to 6nm if the tracks are 90 degrees apart rather that 15nm and 30 degrees. This or similiar apply to anyone else?

[rennaps]

Usually, deemed separation is established when the ICAO Pans-Ops obstacle protection areas do not overlap. Procedurally separated holding patterns are when the primary obstacle protection areas for the holdings do not overlap.

[1Charlie]

NZ VOR or RNAV tracking minimum lateral sep is 24 degrees and 8nm up to A100

Provided an aircraft is contained on a visual app or an instrument app an aircraft may depart into a sector separated by 45* from the arrival area (Aircraft's present track to final app track) until the arriving aircraft is within 3 mins from the airfield. This may be used when the arriving aircraft is making a base turn approach from the overhead provided the aircraft has reported established outbound.

[7478ti]

Consider adopting modern RNP based procedures for traffic separation. They have been used successfully now for well over a decade, in several states in particular, even for far more critical terrain separation. RNP is also used internationally, at higher RNP levels, such as for oceanic and remote area traffic separation. If you have suitable fractions of FMS RTA equipped aircraft operating at the relevant airfields, or regions, use of RTA in conjunction with 3D RNP procedures can also help.

Regards,
ti