Unfortunately, we don’t fly with three in the cockpit anymore – or even four. The navigators job falls squarely onto the front two seats. Over one weekend in April there was one Gross Navigation Error, and two close calls reported on the North Atlantic.
April 22nd (Friday)
Democratic Republic of the Congo Boeing 727 100 (9QCDC/DRC001) from Santa Maria Island, Azores (LPAZ) to St. John’s NL (CYYT)
At 1235Z, Observed on radar to be over position 4720N 4745W, which was approximately 60 miles north of the cleared route 45N 45W – 47N 50W. The crew reported correctly while in oceanic airspace. The flight was cleared direct to YYT and landed without incident at CYYT. There was no traffic, and no other impact to operations.
April 24th (Sunday)
Neos Airline Boeing 767-300 (INDDL/NOS730) from Ferno, Italy (LIMC) to Havana, Cuba (MUHA)
Cleared via 49N030W 48N040W 45N050W. At 30W, the flight reported 48N040W 44N050W. The aircraft recleared to 45N050W prior to proceeding off course.
Apr 25th (Monday)
Transportes Aereos Portugueses Airbus A330-202 (CSTOO/TAP203) from Lisbon, Portugal (LPPT) to Newark, NJ (KEWR)
Cleared 46N030W 46N040W 45N050W. The aircraft reported proceeding via 46N030W 46N040W 44N050W, as per the original flight plan. The aircraft was recleared via 45N050W prior to proceeding off course.
Did you notice how hard it was to find the error in the above two examples?
Gross Navigation Errors are a really interesting topic, and relevant not just on the North Atlantic but in any Oceanic or Remote airspace where ATC cannot monitor the aircraft tracking.
What defines a GNE? Normally, 25nm: That is, when on “own navigation” the aircraft departs the cleared route by more than 25nm. The NAT Central Monitoring Agency (CMA) now defines a Gross Navigation Error as 10nm instead of 25nm.
Annually, the biggest offenders in order of “market share” are: 1. Corporate/Private, 2. Military/State 3. Civil airlines.
How to Avoid a GNE?
(aka How to avoid a Nastygram from the Authorities):
In general, when operating outside of ATC Radar coverage in any airspace:
- Crews: Don’t have more than one paper copy of the Flight Plan in the cockpit. Mark the active one “Master Document”. Hide any other copies where you won’t find them.
- Ops: If you send a new Flight Plan to the crew, tell them what the changes are – especially if you’ve filed a different route in Oceanic or Remote Airspace.
- Fly the Clearance, not the Filed Plan. This is the biggest gotcha. As soon as you reach the Oceanic Entry Point, or leave radar airspace – refer only to the most recent Clearance from ATC. The filed plan is a request only – sounds obvious, but most GNE’s occur because the crew fly the filed plan although there was a reroute.
- Be aware of the ‘ARINC424 problem’: In the aircraft FMS, and map display, the current common waypoint format is 5230N for position 52N030W (as prescribed by ARINC 424). To show position 5230N030W – ARINC 424 offers a format N5230. The potential for confusion is clear. ICAO, in NAT Ops Bulletin 3/15, have recommended that operators use the format H5230, if a five-letter FMS format waypoint is required. In addition pilots are recommended to cross check any waypoints that don’t have a ‘name’.
- Use a plotting chart – it’s mandatory. You don’t have to use ours, but use one.
- Use an Oceanic/Remote Area Checklist (sample link below).
And specifically on the Atlantic:
- Read the advice on the Daily Track Message – waypoint cross check, Fly the Clearance (and be sure it is the clearance!)
- Know the weather deviation procedures: Even with the new “Half Tracks”, there are no changes to the in flight contingency procedures and weather deviation procedures as detailed in PANS ATM Doc444 Para15.2 & 15.2.3.
Here’s some links and resources that we think are really useful:
- Sample Oceanic Paperwork
- Oceanic Checklist
- Oceanic Plotting Chart
- ICAO: Gross Navigation Errors: NAT Ops Bulletin 02/2014
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