Why all the fuss about plotting procedures and checking Flight Management System programming over and over again when flying oceanic? If you download the FMS waypoints from the same people who filed the flight plan, what can go wrong? What indeed.
First, let's tackle the actual reason why. No matter where you fly, human error can creep into FMS programming (even when it is downloaded), flight plan transmission to ATC, and a failure of either of these things with any of the other aircraft you share the sky with. When you fly domestically, however, you normally have someone watching you on radar and in most parts of the world, a computer is watching for conflicts in real time. You don't have that when flying oceanic. So that's the why.
Second, let's talk about the likelihood of something going wrong when oceanic. You've been doing this for years and can't remember the last time you had a problem. Maybe you've never had a problem. But you've heard that general aviation has 10 percent of the traffic and 90 percent of the GNE's. That just isn't true. I've talked to oceanic controllers who say most of the problems come from military flights and from several third world countries. Of those that remain, the number of problems from the airlines and general aviation are about the same, despite the fact there are so many more airliners. The difference, I think, is that the system gets most of its funding from the airlines and they are willing to overlook their transgressions more easily.
We aren't here to point fingers, only to illustrate that GNEs do occur and that we need to be careful.
What follows comes from the references shown below. Where I think it helpful, I've added my own comments in blue.
[ICAO NAT Doc 007, ¶8.1.6] Obviously, there are several combinations of airborne sensors, receivers, computers with navigation data bases and displays which are capable of producing like accuracies, and which with inputs to automatic flight control systems provide track guidance. However, regardless of how sophisticated or mature a system is, it is still essential that stringent navigation and cross checking procedures are maintained if Gross Navigation Errors (GNEs) are to be avoided. A GNE within NAT Airspace is defined as a deviation from cleared track of 25 NM or more. Some of these errors are detected by means of long range radars as aircraft leave oceanic airspace. Other such errors may also be identified through the scrutiny of routine position reports from aircraft.
[Flight Service Bureau] The NAT Central Monitoring Agency (CMA) now defines a Gross Navigation Error as 10nm instead of 25nm.
[ICAO NAT Doc 007, ¶15.3.1] The most common causes of GNEs, in approximate order of frequency, have been as follows:
[ICAO NAT Doc 007, ¶15.3.2] To illustrate the surprising nature of things which can go wrong, the following are examples of some extremely rare faults which have occurred:
I was once flying from Anchorage, Alaska to Tokyo, Japan when our navigator made the classic east versus west error in our longitude. When the INS got to that waypoint the airplane made a sharp right turn. That was a good thing, it got all of our attentions. We were lucky it wasn't a more subtle error.
I was once asked to audit a company GNE where the crew simply downlinked the Europe to White Plains flight plan from satellite and saw 99 waypoints loaded but for some reason KHPN was missing from the last leg. They typed in KHPN and called it good. At 30°W the airplane cycled from the 99th waypoint, which was at 30°W, directly to KHPN. The crew wasn't plotting or even monitoring headings at each waypoint. I recommended the crew be required to face the consequences.
[ICAO NAT Doc 007, ¶16.1] During the monitoring of navigation performance in the NAT MNPS (HLA) airspace, a number of lateral deviations are reported. There were 57 in 2012 and 66 in 2013. A lateral deviation of 25NM or greater is classified as a Gross Navigation Error (GNE). Of the 57 lateral deviations in 2012 19 were GNE’s and of the 66 lateral deviations in 2013 10 were GNE’s. Such errors are normally detected by means of long range radars as aircraft leave oceanic airspace but are increasingly confirmed by means of ADS-C waypoint reporting. In addition, however, on 51 occasions in 2012 and 71 occasions in 2013, potential navigation errors were identified by ATC from routine aircraft position reports (from “next” or “next plus one” waypoints) and ATC were able to intervene to prevent incorrect routing by the aircraft. The vast majority of these instances were attributable to a crew error of following of the filed flight plan route rather than the cleared route.
[ICAO NAT Doc 001, ¶5.5]
[ICAO NAT Doc 001, ¶5.10] Follow-up Action on Observed and Reported GNEs
In other words, they will be contacting the FAA. But what happens after that? I've asked and have never heard of certificate action as a result. The worst thing will be on behalf of the operator (or your owner). So, given that, what is the motivation? The answer is the obvious one: you don't want to hit anything or become lost.
[ICAO NAT Doc 007, ¶15.4] Never relax or be casual in respect of cross-check procedures. This is especially important towards the end of a long night flight.
Cross-checks begin approaching each waypoint. See: International Operations / En Route / Approaching Each Waypoint.
[ICAO NAT Doc 007, ¶15.4] Avoid casual R/T procedures. A number of GNEs have been the result of a misunderstanding between pilot and controller as to the cleared route and/or flight level. Adhere strictly to proper R/T phraseology and do not be tempted to clip or abbreviate details of waypoint coordinates.
[ICAO NAT Doc 007, ¶15.4] Make an independent check on the gate position. Do not assume that the gate coordinates are correct without cross-checking with an authoritative source. Normally one expects coordinates to be to the nearest tenth of a minute. Therefore, ensure that the display is not to the hundredth, or in minutes and seconds. If the aircraft is near to the Zero Degree E/W (Greenwich) Meridian, remember the risk of confusing east and west.
Systems that use GPS for initialization are far less likely to have this problem. Make sure you follow your aircraft manufacturer's latest procedures. I once flew a Challenger 604 that allowed the initialization be updated at the end of the runway but the procedure discouraged this practice if GPS was installed. Some of our pilots would always update the initialization with runway position because that's what they did before GPS. They were, of course, decreasing the accuracy of the system.
[ICAO NAT Doc 007, ¶15.4] Always return to the ramp and re-initialize inertial systems if the aircraft is moved before the navigation mode is selected. If after getting airborne, it is found that during initialisation a longitude insertion error has been made, unless the crew thoroughly understand what they are doing, and have also either had recent training on the method or carry written drills on how to achieve the objective, the aircraft should not proceed into NAT HLA airspace, but should turn back or make an en-route stop.
[ICAO NAT Doc 007, ¶15.4] Before departure, at least two pilots should independently check that the following agree: computer flight plan, ICAO flight plan, track plotted on chart, and if appropriate, the track message. In flight, involve two different sources in the cross- checking, if possible. Do not be so hurried in loading waypoints that mistakes become likely, and always check waypoints against the current ATC clearance. Always be aware that the cleared route may differ from that contained in the filed flight plan. Prior to entering the NAT HLA ensure that the waypoints programmed into the navigation computer reflect the Oceanic Clearance received and not any different previously entered planned or requested route.
[ICAO NAT Doc 007, ¶15.4] Before entering Oceanic Airspace make a careful check of LRNS positions at or near to the last navigation facility – or perhaps the last but one.
There are many ways to do this, some more accurate than others. See: International Operations / Navigation Accuracy Check.
[ICAO NAT Doc 007, ¶15.4] Never initiate an on-track uncleared level change. If a change of level is essential and prior ATC clearance cannot be obtained, treat this situation as a contingency and execute the appropriate contingency offset procedure, when possible before leaving the last cleared flight level. Inform ATC as soon as practicable.
This may seem almost nonsensical but it does happen. See: International Abnormal Procedures / Loss of RVSM Capability in Oceanic Airspace and International Abnormal Procedures / Weather Deviation in Oceanic Airspace.
[ICAO NAT Doc 007, ¶15.4] Do not assume that the aircraft is at a waypoint merely because the alert annunciator so indicates. Cross-check by reading present position.
[ICAO NAT Doc 007, ¶15.4] Flight deck drills. There are some tasks on the flight deck which can safely be delegated to one member of the crew, but navigation using automated systems is emphatically not one of them, and the Captain should participate in all navigation cross-check procedures. All such cross-checks should be performed independently by at least two pilots.
[ICAO NAT Doc 007, ¶15.4] Use a flight progress chart on the flight deck. It has been found that making periodic plots of position on a suitable chart and comparing with current cleared track, greatly helps in the identification of errors before getting too far from track.
Pilot message boards are filled with self-assured oceanic pilots claiming plotting is unnecessary. "I've been flying oceanic for thirty years," some of these will say, "and I've never plotted!" What you don't see are comments from all those sorry saps who got caught by personal error or just plain circumstance who could have been saved by a plotting chart. I've met several seasoned veterans who simply didn't know how and were afraid to admit that. Well, help is on the way: Navigation / Plotting 101.
It is very easy to find yourself with several copies of your flight plan as the trip planners flood you with paperwork and the trip evolves with changing winds and finally the actual clearance. The best way to avoid using the wrong information is to keep that information out of the cockpit in the first place. Even if you have two versions of the exact flight plan, you are unlikely to annotate both with changes. Once you've decided which flight plan is your master document, annotate it as such and purge all other copies from the cockpit.
[ICAO NAT Doc 007, ¶8.2.6] Misuse of the Master Document can result in GNEs occurring and for this reason strict procedures regarding its use should be established. These procedures should include the following:
I think this is a poor technique but if you insist on giving both pilots a copy, ensure only one says "MASTER DOCUMENT" on it and do not write on the other copy to avoid confusing which one has the relevant data. Once you get into the second page of the flight plan it is easy to lose sight of which one is the actual master document.
ICAO NAT Doc 001, Guidance and Information Material Concerning Air Navigation in the North Atlantic Region, Seventh Edition, January 2002
ICAO NAT Doc007, North Atlantic Operations and Airspace Manual, v 2016-1