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

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

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

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

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

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

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

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

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)

page 10 Traffic Concentration 24 May 2006

page 11 Traffic Streaming

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

page 13 Thank you for listening