ASSTAR Oceanic Applications
by Nico de Gelder, NLR
ASSTAR User Forum #1
4 April 2006, Roma
Overview
 General Introduction
 Oceanic ASAS Applications
– In Trail Procedure (ATSA-ITP)
– In Trail Procedure (ASEP-ITP)
– In Trail Follow (ASEP-ITF)
– Free Flight on an Oceanic Track (SSEP-FFT)
page 2
General Introduction
 Oceanic Environment
– Focus on the Organised Track System

Operational limitations caused by procedural separation standards

Structured system with potentially large benefits
– North Atlantic OTS is characterized by:

5-6 parallel tracks

Longitudinal separation of 10-15
minutes

Lateral separation of 60 NM

Vertical separation of 1,000 ft
page 3
General Introduction
 Oceanic Environment (cont’d)
– Reduction of Oceanic Separation is studied (RNP-4, 30/30 Separation)

30 mile lateral and longitudinal separation

Standards call for:
– Direct controller-pilot communication via voice or data link
– Aircraft navigation accuracy to RNP-4
– Appropriate ADS-C position reporting capability (air and ground)

Implementation from 2009 onwards
– starting with RNP-4, 30 mile longitudinal separation on one or two OTS
tracks
page 4
General Introduction
 Airborne ASAS application categories defined by FAA/Eurocontrol (in
PO-ASAS document)
– Airborne Traffic Situation Awareness (ATSA)

Neither delegation of separation responsibility nor delegation of tasks

In Trail Procedure (ATSA-ITP)
– Airborne Spacing (ASPA)
– Airborne Separation (ASEP)

Limited delegation of separation responsibility and associated tasks

In Trail Procedure (ASEP-ITP)

In Trail Follow (ASEP-ITF)
– Airborne Self-Separation (SSEP)

Full delegation of separation responsibility and associated tasks

Free Flight on an Oceanic Track (SSEP-FFT)
page 5
In Trail Procedure
Airborne Traffic Situation Awareness application
(ATSA-ITP)
page 6
In Trail Procedure (ATSA-ITP)
Other aircraft
Other aircraft
FL360
Other aircraft
ITP Aircraft
Reference Aircraft
FL350
ITP
Criteria
Standard
Longitudinal
Separation Requirement
FL340
Standard
Longitudinal
Separation Requirement
page 7
In Trail Procedure (ATSA-ITP)
 Anticipated Benefits
 enabling more frequent flight level changes for better flight efficiency
(fuel savings)
 improved safety by avoiding turbulent flight levels
 Requirements Focus Group (RFG)
– is creating standards for this application
– as part of ASAS Package 1
page 8
Initial Procedures for ATSA-ITP
 Flight Crew (given own aircraft/flight crew is qualified for ATSA-ITP)
– determine the need to climb/descend (at least) 2,000 ft
– check for Potentially Blocking Aircraft at intermediate level
– check for compliance with ATSA-ITP initiation conditions

Potentially Blocking Aircraft Reference Aircraft
– request ATSA-ITP flight level change with Reference Aircraft
 Example ATSA-ITP initiation conditions are:

procedural separation exists at the desired flight level

potentially blocking aircraft has qualified ADS-B Out

distance from the blocking aircraft exceeds 15 (or 20) NM

closure rate does not exceed 20 (or 30) kts

own aircraft (ITP aircraft) can climb with at least 300 fpm
page 9
Initial Procedures for ATSA-ITP (cont’d)
 Oceanic Controller
– check

Reference Aircraft is the only blocking aircraft

speed difference is less than 0.03 Mach

Reference Aircraft has not been cleared to manoeuvre
– issue ATSA-ITP clearance for a climb/descent (typically 2,000 ft)
 Flight Crew
– re-assess ATSA-ITP initiation conditions
– respond to ATSA-ITP clearance
– perform ATSA-ITP climb/descent

normal climb/descent with at least 300 fpm

monitoring of reference aircraft is not required
– report established at the new flight level
page 10
In Trail Procedure
Airborne Separation application
(ASEP-ITP)
page 11
In Trail Procedure (ASEP-ITP)
Other aircraft
Other aircraft
FL360
Other aircraft
ITP Aircraft
Reference Aircraft
FL350
ITP
Criteria
Standard
Longitudinal
Separation Requirement
FL340
Standard
Longitudinal
Separation Requirement
page 12
In Trail Procedure (ASEP-ITP)
 Expected Benefits
 enabling more frequent flight level changes for better flight efficiency
(fuel savings)
 improved safety by avoiding turbulent flight levels
 ASEP-ITP enables the controller
– to designate a Reference Aircraft as Target Aircraft, and
– to instruct the Clearance Aircraft

to climb/descend to a new flight level, and

to provide separation with the Target Aircraft
 And the clearance aircraft (after receipt of the clearance)
– to ensure that airborne longitudinal separation minimum is not infringed
– to climb/descend to the instructed level
page 13
Initial Procedures for ASEP-ITP
 Flight Crew (aircraft/flight crew qualified for ASEP-ITP)
– determine the need to climb/descend (at least) 2,000 ft
– check for Potentially Blocking Aircraft at intermediate flight level
– check for compliance with ASEP-ITP initiation conditions

Potentially Blocking Aircraft Reference Aircraft
– request ASEP-ITP flight level change with Reference Aircraft
 Example ASEP-ITP initiation conditions are:

procedural separation exists at the desired flight level

potentially blocking aircraft has qualified ADS-B Out

distance from the blocking aircraft exceeds 10 (or 15) NM

closure rate does not exceed 20 (or 30) kts

(or a more advanced distance/closure rate function)
page 14
Initial Procedures for ASEP-ITP (cont’d)
 Oceanic Controller
– check

Reference Aircraft is the only blocking aircraft

speed differences are less than 0.03 Mach (due to ADS-B limitation)

Reference Aircraft has not been cleared to manoeuvre
– issue ASEP-ITP climb/descent clearance
 Flight Crew
– respond to ASEP-ITP clearance
– perform ASEP-ITP climb/descent

monitor and maintain longitudinal separation
with Target Aircraft
– report established at the new flight level
page 15
Initial Procedures for ASEP-ITP (cont’d)
 Questions / Discussion Items
– ASEP-ITP is strongly based on ATSA-ITP, to enable a step-by-step
application development. Do you agree with this approach?
– Added benefit of ASEP-ITP is limited, unless ...
page 16
In Trail Follow
Airborne Separation application
(ASEP-ITF)
page 17
In Trail Follow
B
A
Required minutes-in trail
maintained by ASEP-ITF
Oceanic
Entry
Point
page 18
In Trail Follow
FL360
Other aircraft
ITF Aircraft
Target Aircraft
FL350
Airborne
Sep
Standard
Longitudinal
Separation Requirement
FL340
Standard
Longitudinal
Separation Requirement
Instructed
spacing
distance
page 19
In Trail Follow
 Anticipated Benefits
 enabling more frequent flight level changes for better flight efficiency  fuel
savings
 reduced controller workload
 enabling more aircraft to fly on the flight levels of an oceanic track  improved
track occupancy
 ASEP-ITF enables the oceanic controller
– to designate an aircraft as Target Aircraft
– to instruct the Clearance Aircraft

to remain behind the Target Aircraft, for example 2 minutes, and

to provide longitudinal separation with the Target Aircraft, for example 5 miles
 And the clearance aircraft must (after receipt of the clearance)
– acquire and maintain the instructed spacing
– ensure that the airborne longitudinal separation minimum is not infringed
page 20
Initial Procedure for ASEP-ITF
 Flight Crew (ITF case during Oceanic Ops)
– determine the need to climb/descend (at least) 1,000 ft
– check for Potentially Blocking Aircraft
– check for compliance with ASEP-ITF initiation conditions
– request ASEP-ITF flight level change with Lead Aircraft

Potentially Blocking Aircraft Lead Aircraft
 Example ASEP-ITF initiation conditions are:

potentially blocking aircraft has qualified ADS-B Out

potentially blocking aircraft is flying ahead of own aircraft

spacing with blocking aircraft exceeds 2 minutes

speed difference less than 0.03 Mach

but ... a more advanced spacing/speed function is anticipated, e.g. based
on the current sliding Mach technique
page 21
Initial Procedure for ASEP-ITF (cont’d)
 Oceanic Controller (ITF case during Oceanic Ops)
– check

Lead Aircraft is the only blocking aircraft

Lead Aircraft has not been cleared to manoeuvre
– issue ASEP-ITF climb/descent clearance

an exact Spacing Time, or

a Spacing Time bracket
(with Max value in instruction)
page 22
Initial Procedure for ASEP-ITF (cont’d)
 Flight Crew (ITF case during Oceanic Ops)
– respond to ASEP-ITF climb/descent clearance
– insert appropriate data in on-board system
– execute ASEP-ITF manoeuvre

acquire and maintain spacing value (typically 2 to 9 min)

provide longitudinal separation with lead aircraft
– climb/descend, report established at new flight level
– ASEP-ITF continues until cancelled by controller
 Oceanic Controller
– cancel ASEP-ITF

in relation with a climb/descent instruction

at the oceanic exit point
page 23
Initial Procedure for ASEP-ITF (cont’d)
 Questions / Discussion Items
– In case of climb/descent and then follow

Combined ITF-flight level instruction by the oceanic controller

First an ITF instruction, and thereafter a climb/descent instruction
– In case of ITF instruction at the oceanic entry point

Instruction to be given by domestic tactical controller
– ADS-B message set

needs to be expanded with Mach number or something similar
– Provision of airborne longitudinal separation

implicit as part of maintaining (a larger) spacing value including tolerances
– Speed range during ASEP-ITF

needs to be predictable, due to non-ITF aircraft behind the ITF pair

trade-off between (near-)optimal speed and (near-)optimal altitude
page 24
Free Flight on an Oceanic Track
Airborne Self-Separation application
(SSEP-FFT)
page 25
Free Flight on an Oceanic Track
Vertical Profile
Predicted Position
T minutes ahead
Predicted
Protection Zone
Traffic
Ownship
Vertical Resolution
Horizontal Profile
Predicted Position
Predicted
T minutes ahead
Protection Zone
Speed Resolution
Ownship
Traffic
page 26
Free Flight on an Oceanic Track
 Anticipated Benefits
 enabling more aircraft at the flight levels of a track (due to lower longitudinal
separation criteria)
 enabling more frequent flight level changes or even cruise climbs
 enabling more freedom in speed selections
 these factors contribute to better flight efficiency, improved track occupancy
and improved safety
 controller workload reduction
 SSEP-FFT characteristics
– Separation responsibility relative to all aircraft on the Free Flight Track is
transferred to the flight crew, for an extended period of time
– New entry/exit procedures will be required

aircraft will receive a clearance to enter the Oceanic Free Flight Track

aircraft will receive a clearance to return to managed airspace
– An Oceanic Free Flight Track has to be defined (in space, in time, legally)
page 27
Initial Procedures for SSEP-FFT
 Flight Crew (given aircraft/flight crew are qualified)
– Request oceanic clearance for Free Flight Track

between 90 and 30 minutes from reaching the oceanic boundary, as today
 Oceanic Planner Controller
– Check flow management issues

apply same or similar oceanic entry criteria as today
– Issue oceanic clearance for Free Fight Track
page 28
Initial Procedures for SSEP-FFT
 Flight Crew
– Respond to oceanic clearance, including confirmation of FFT exit
conditions with new estimates (if any)
– At the Oceanic Entry Point

Engage Free Flight mode

Transfer to Flight Information frequency Flight Crew
– Provides separation with all other aircraft on the Free Flight Track

Conflict Prevention, Conflict Detection and Conflict Resolution functions

Resolutions only in the vertical and speed domain

Appropriate display information and crew alerting
page 29
Initial Procedures for SSEP-FFT
 Flight Crew
– about 30 minutes from leaving oceanic airspace

contact Domestic Planning controller

request domestic airspace entry clearance
 Domestic Planning Controller
– issue clearance for entering domestic airspace

if acceptable based on requested exit point, time and flight level

controller may choose to offer an alternative clearance with a different flight
level

clearance also includes a domestic frequency to contact on entering
domestic airspace and a Mode A squawk
page 30
Initial Procedures for SSEP-FFT
 Flight Crew
– At the Oceanic Exit Point (i.e. domestic airspace entry point)

contact Domestic Tactical controller

disengage Free Flight Mode
page 31
Initial Procedures for SSEP-FFT
 Questions / Discussion Items
– Contacting a Domestic Planning controller?

planning controller currently has no access to a radio frequency (R/T)

ground system provisions in case of CPDLC (downstream clearance)

but ... we do not want to mandate CPDLC

though ... CPDLC is most likely mandated in the NAT prior to FF track deployment
– No horizontal resolutions

to avoid impact adjacent OTS tracks

no horizontal resolutions until proven to be really necessary
– Oceanic Free Flight Track(s) parallel to the OTS tracks

in between the existing OTS tracks, or

after RNP-4 implementation one of the OTS tracks will be designated as FF track
– Roll-out / roll-up of the Free Flight Track
– Local GNSS failure

A second GNSS - Galileo

A relatively low RNP value (e.g. RNP-4) – have some hours before exceeding RNP
page 32
THANK YOU
page 33
FEEDBACK
QUESTIONS
COMMENTS
and
NEW IDEAS
SUGGESTIONS
P.S. Feel free to send afterthoughts to degelder@nlr.nl
page 34