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Discussion of Issues regarding ARINC 424, 7.2.5

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).

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Discussion of Issues regarding ARINC 424, 7.2.5

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  1. 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 KraftMobile: 202-369-2168Email: tom.kraft@faa.gov

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. ARINC 424, 7.2.5,CurrentProposedNaming ConventionCriteria 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

  8. Obviously LARGE– Distance Error – Unnoticeably SMALL PREFIX/SUFFIX– Placement – PREFIX/SUFFIX(ONLY)INFIX/MIDFIX 8 new characters – Letters – (4) direction letters No N, S, E, or W – eliminates risk of confusionwith waypoint coordinates Also, allows fewer placement perturbations

  9. Discussion topics

  10. Note: While shown, current ARINC 424 does not address duplicate names at Equator, Prime Meridian and 180th meridian lines. NAT Region NAT Region

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