1. ASSTAR Airborne Separation Operations in Oceanic Airspace Bob McPike, NATS ASAS-TN2 Conference Glasgow, September 2006

2. page 2 Overview  Background to oceanic operations  ASAS operations to improve flight flexibility  ASAS operations to manage airspace congestion

3. page 3 Oceanic Communications  No VHF Radio or radar cover over most of the North Atlantic Region (NAT)  Voice communications provided by High Frequency (HF) Radio  HF subject to weather effects –Audibility can be limited –Sometimes communication is impossible  So ATC issues strategic clearances –Issued prior to entering an oceanic Flight Information Region (FIR) –Extend from Oceanic Control Area (OCA) entry to landfall –Long-term conflict prediction used to ensure no separation loss over whole route

4. page 4 Oceanic Separation Standards  Separation standards governed by various uncertainties: –Communication unreliability –Navigational accuracy –Accuracy of forward estimates (driven by weather forecasts)... so separation standards are very large 10 mins 60 miles 1000 ft 15 mins

5. page 5 ASAS in Oceanic Airspace  ASAS concepts under consideration by ASSTAR for oceanic airspace –In-Trail Procedure (ATSA-ITP and ASEP-ITP) –In-Trail Follow (ASEP-ITF) –Self-Separation on a Free-Flight Track (SSEP-FFT)  Status –Concepts and procedures defined –Simulations will be conducted in Amsterdam November 2006 to March 2007

6. page 6 In-Trail Procedure FL340 FL360 FL350 > 10 mins ATSA-ITP Criteria Aircraft at FL340 would like to climb ….. But standard longitudinal separation does not exist at level above Crew request an ITP Climb 5 mins

7. page 7 In-Trail Follow 5 mins 5 minutes : No standard longitudinal separation ITF Airborne Separation Established: In-Trail Follow Climb Approved, Maintaining In-Trail Airborne Separation In-Trail Separation maintained over extended period Second climb approved –Maintaining ITF Separation In-Trail Follow cancelled Exit Oceanic Airspace FL360 FL350 FL340

8. page 8 Self-Separation on a Free-Flight Track  Concept still in the early stages of development  FFT is an OTS track reserved for ASAS-capable aircraft  Aircraft on the track can change speed and level at their own discretion... but no lateral flexibility allowed  Aircraft requires downstream clearance to re-enter managed airspace

9. page 9 Using ASAS to manage airspace congestion  Oceanic/Domestic Interface - a Plumbing Problem? –Narrow ‘pipes’ in European/North American regions –European pipework highly complex (lots of crossing and converging traffic)

10. page 10 Traffic Concentration 24 May 2006

11. page 11 Traffic Streaming

12. page 12 Tactical re-routes in the NAT 15 minutes 4 minutes ITF

13. page 13 Thank you for listening bob.mcpike@nats.co.uk