Discussion of Issues regarding ARINC 424, 7.2.5 26 August 2014 Presented to: NAT IMG Decision 44/4 – Ad-Hoc Task Force By: Tom Kraft Mobile: 202-369-2168 Email: tom.kraft@faa.gov

Background (1 of 2) April to May 2014 – NAT ANSPs reported increase in lateral deviations where aircraft began flying offsets one-half degree to the north of their cleared route 3 Apr 2014 – navigation data base update added new half-degree waypoints using ARINC 424, 7.2.5; Operators were not notified/unaware of change Suspect incorrect ARINC 424, 7.2.5, fix name used; verification procedure not used or ineffective 26 Apr 2014 – Gander (NavCanada) issued NOTAM to raise awareness of the issue (A3151/14 refers) Indication of lateral deviation was not obvious or readily detectable Flight crew display of active route does not show lateral deviation; only achieved by verification of full coordinates for the waypoint using another pilot-selectable display Controller can only detect lateral deviation using ADS-C or ATS surveillance service (e.g. radar); flight crew usually reported the position on the cleared route, not the actual aircraft position, which was incorrect

Background (2 of 2) Before Apr 2014, if ARINC 424, 7.2.5, waypoint name entered incorrectly, flight crew would receive an error message – not in the data base 29 May 2014 – New half-degree waypoints removed from data base 16 May 2014 – NAT IMG Decision 44/4 – U.S. would coordinate, as necessary, to investigate issues with use of ARINC 424, 7.2.5, and recommend mitigations for consideration by the NAT SPG groups Since May – U.S. has been coordinating via eMail and held three Web Ex meetings Today – Ad-Hoc Task Force WebEx – To understand the issues with current ARINC 424, 7.2.5, naming convention and review proposed changes 4-5 Sep 2014 – Ad-Hoc Task Force Meeting (Paris) – to review and agree on a strategy for resolving issues with the use of half-degree waypoints 22-26 Sep 2014 – NAT CNSG/11 (Prestwick) – contributory group to the NAT IMG 21-23 Oct 2014 – related AEEC (ARINC 424) Standards Meeting (Tucson, AZ) 4-7 Nov 2014 – NAT IMG/45 (Paris) – contributory group to the NAT SPG

Purpose of ARINC 424, 7.2.5, review To understand the issues with current ARINC 424, 7.2.5, naming convention and how its use contributes to potential lateral deviations Review proposed revision to ARINC 424, 7.2.5 Other perspectives to consider Human factors Global and ATC implications Conflicts with other naming conventions and schemes for entering waypoints Concept of use, flight crew procedures and training Cost and timeline to implement the proposed solution Contents of this presentation only represents work in progress and does not represent a position of the Ad-Hoc Task Force or any party

Current thinking Operational trials of “half-degree” tracks are planned in the NAT Organized Track System in Nov 2015 When using ARINC 424, 7.2.5, naming convention to routinely define ATC routes using half-degree waypoints, mitigation is needed to ensure an acceptable risk of lateral deviations Procedures and training are essential to verify full coordinates of waypoints entered by the flight crew, but are NOT in and of themselves the solution to the problem Other potential means to mitigate the risk of lateral deviations need to be considered. Including: Loading route information directly from CPDLC clearances (but only if aircraft capable) Using published waypoint names for half-degree waypoints Entering full coordinates for waypoints

Current ARINC 424, 7.2.5, issues Entering incorrect waypoint name can result in a small distance error (approximately 30 miles off of cleared route) that is not readily obvious to flight crew from displayed active route 6230N being 62°N 30°W N6230 being 62°30’N 030°W Placement of the four letters that signify cardinal direction (N, S, E and W) is the only discriminator for Longitudes < or > 100° longitude Whole and half-degrees latitude Waypoint name can conflict with lines of latitude or longitude in an ATC instruction, such as CROSS [line of latitude] at FL350 6230N being 62°N 30°W, per ARINC 424, 7.2.5 6230N being 62°30’N as [line of latitude] in ATC instruction Prefix/suffix confusion One mistake can cause error Same name, but different meaning

ARINC 424, 7.2.5, Current Proposed Naming Convention Criteria Geographical coordinates for fix Latitude Longitude xx° [00‘ or 30’] [N or S] [1]yy° [E or W] where xx = 2 integers representing degrees of latitude where [1]yy = 2 or 3 integers representing the degrees of longitude Core fix name convention format from source xx[1]yy 8 letters, different from those used for cardinal direction 2 different letter placements 4 letters, same as used for cardinal direction 4 different letter placements Letter assignment for fix names Quadrant (See Notes) Letter to use, if latitude 00’ (Whole °) 30’ (Half °) Northwest N Northeast E Southeast S Southwest W Letter assignment for fix names Quadrant (See Notes) Letter to use, if latitude 00’ (Whole °) 30’ (Half °) Northwest A H Northeast B J Southeast C K Southwest D L Letter placement for fix names If fix latitude whole ° If fix latitude half ° then, if longitude > 100° < 100° xx[1]yy xxyy[suffix] x[Ltr]xyy [prefix]xxyy where the assigned letter replaces [1] where the assigned letter replaces [suffix] where the assigned letter replaces [Ltr] where the assigned letter replaces [prefix] Letter placement for fix names If fix latitude whole ° If fix latitude half ° then, if longitude > 100° < 100° xxyy[suffix] [prefix]xxyy where the assigned letter replaces [suffix] where the assigned letter replaces [prefix] where the assigned letter replaces [prefix]

Obviously LARGE – Distance Error – Unnoticeably SMALL Proposed Change to ARINC 424, 7.2.5, Naming Convention Current Scheme Quadrant Latitude Longitude Half Degree Whole Degree Northwest (incl. NAT) 00° ≤ xx ≤ 89°30’ 001° < yy < 099° Hxxyy xxyyA xNxyy xxNyy 100° < 1yy < 179° xxyyH Axxyy Nxxyy xxyyN Northeast 000° < yy < 099° Jxxyy xxyyB xExyy xxEyy 100° < 1yy < 180° xxyyJ Bxxyy Exxyy xxyyE Southeast 00°30’ ≤ xx ≤ 89°30’ Kxxyy xxyyC xSxyy xxSyy xxyyK Cxxyy Sxxyy xxyyS Southwest Lxxyy xxyyD xWxyy xxWyy xxyyL Dxxyy Wxxyy xxyyW North Pole 90° N 000° W [TBD] South Pole 90° S Notes If fix located on Use letter assigned to Equator North quadrants Prime Meridian or 180th meridian East quadrants Note.— Current ARINC 424, 7.2.5, does not address fix names at Equator, Prime Meridian, 180th meridian, North Pole and South Pole. PREFIX/SUFFIX – Placement – PREFIX/SUFFIX (ONLY) INFIX/MIDFIX 8 new characters – Letters – (4) direction letters No N, S, E, or W – eliminates risk of confusion with waypoint coordinates Also, allows fewer placement perturbations

Discussion topics Topic What is the potential for flight crew errors? How would errors be detected and corrected? (trapped) What is the effect of uncorrected flight crew errors? What is the complexity of mental model needed to process the waypoints? Does the proposed naming scheme conflict with any other naming schemes or data entry conventions? Is the naming convention compatible with existing avionics and data bases? Does the naming convention yield a unique and unambiguous identifier for the fix? Can the naming convention be used to name fixes with whole or half-degree latitude and whole degree longitude anywhere on the globe? What is the effect on flight crew training and procedures? Can the naming convention be used by ATC – Is it compatible with existing systems? What would be the effect on air traffic controller training and procedures?

Note: While shown, current ARINC 424 does not address duplicate names at Equator, Prime Meridian and 180th meridian lines. Current ARINC 424, 7.2.5, Naming Convention Northwest Longitude Northeast 179°W-100°W 099°W-000°W 000°E-099°E 100°E-180°E Latitude 90°N–00°N xNxyy Nxxyy Half Exxyy xExyy xxNyy xxyyN Whole xxyyE xxEyy 00°30’S–90°S xxWyy xxyyW xxyyS xxSyy 00°30’S-90°S xWxyy Wxxyy Sxxyy xSxyy Southwest Southeast NAT Region Proposed ARINC 424, 7.2.5, Naming Convention Northwest Longitude Northeast 179°W-100°W 099°W-000°W 000°E-099°E 100°E-180°E Latitude 90°N-00°N Hxxyy xxyyH Half xxyyJ Jxxyy xxyyA Axxyy Whole Bxxyy xxyyB 00°30’S-90°S xxyyD Dxxyy Cxxyy xxyyC Lxxyy xxyyL xxyyK Kxxyy Southwest Southeast NAT Region