Hello aviation professionals. Today I’m going to start with the In the News segment of the podcast, so let’s change gears right away and talk about Micro-SLOP.
ICAO says that Strategic Lateral Offset Procedures or SLOP reduces the vertical collision risk by 78% and is required in the North Atlantic FIRs Gander and Shanwick. SLOP is the offsetting to the right by one or two miles, or not at all. Micro-SLOP is offsetting to the right by increments of 0.1 miles, specifically between 0.1 and 2 NM. This is a new procedure for Atlantic crossings as of August 7, 2019 but should only be employed if your FMS is micro slop capable. In other words, you must be able to program offsets to 0.1.
These changes can be found in the ICAO NAT Document 007 rev2019-3, in section 8.5, pp.79-80.
Today I am going to review the NAT Systems Planning Group sample oceanic checklist, which was released in 2017. While there are many steps to ensure a successful oceanic flight, there are even more steps if something goes wrong, so having a plan or mental picture ahead of time is an advantage. Of course, we can’t prepare for every occurrence, but we can have a mental picture of what we will do if something happens at virtually any time during the flight.
I have talked about this in previous podcasts and it’s important to remember that NAT oceanic contingencies have changed so if you fly through the North Atlantic you may have different contingency procedures depending upon where you are when the failure occurs. Of course, contingency procedures are always non-clearance procedures, so you have been unable to get a new clearance and you need to descend or deviate.
I will be going through the checklist and touching on the points I think are important to highlight. Feel free to send me your comments.
The checklist starts with…
- Flight planning and specifically Communication/Navigation/Surveillance or CNS flight plan codes.
The only way ATC knows what areas of the NAT you are authorized to fly is from your flight plan.
Take a good look at items 10A and B and Item 18 of the ICAO flight plan form or talk to your flight planning provider. Ensure that the appropriate CNS and Performance-based Navigation codes are properly filed for RNP 4 or 10, ABS-C or B, CPDLC etc.
Each aircraft’s MEL should be reviewed for system deferrals that may affect the CNS capabilities of the aircraft.
- Oceanic documents
OFP, NOTAMs, weather, winds (the usual stuff) but have a good review of your
Extended Diversion Time Operations (EDTO) alternates, equal time point locations, and oceanic entry points.
Though most of us probably use an EFB, learning how to plot on paper is an invaluable skill and should be practiced occasionally. This is where International Procedures training is a great idea. Many are in-person initial courses and then follow-up with online recurrent training. Speak with your training provider.
ICAO groups who review oceanic errors have determined that the routine use of a plotting/orientation chart is an excellent aid to reduce lateral errors. Plotting the course can also serve as a critical aid in case of partial or total navigation failure.
The ICAO group found that reading from the OFP and comparing it to the chart can lead to an expectation bias, and this has led to errors based on “seeing what we expect to see”. Therefore, go in the other direction and read from the chart and compare to the OFP.
Plot your route clearance from coast out to coast in. Be sure to update this whenever your route clearance changes.
3. The Track Message if that’s applicable to the flight, and even if it’s not (I’ll expand on that later).
- Equal Time Point (ETP)
ETPs should be computed for contingencies such as medical divert, engine loss or rapid depressurization. Performance with a simultaneous engine loss and rapid depressurization should also be calculated. It is advisable to note the ETPs on the plotting/orientation chart.
Crewmembers should review with each other the appropriate diversion airport(s) when crossing ETPs. Pilot procedures should also include a manual method for computing ETPs.
ICAO recommends that Crews should not enter ETPs in the active route of the Long-Range Navigation System (LRNS) as this could create unwanted alerts on ground-based monitoring systems and could create confusion in the event of a revised route clearance. You can put ETPs in the fix page or something similar so the ETP is visible on the Navigation Display.
- Extended Twin Operations (ETOPS)
Analyze your ETOPS or Extended Diversion Time Operations (EDTO) by verifying that the ETOPS alternates meet the appropriate minutes limitations such as 120, 180, etc.
Identify ETOPS entry and exit points. Also review airspace boundaries for specific contingency procedures for weather deviations and in-flight contingencies and consider plans if any enroute diversion is required. Know where you plan to go at any point along the route.
- Track message Crews
It’s a good idea to have a current track message even if you are filed for a random route or filed above North Atlantic High-Level Airspace. Plotting adjacent tracks and/or crossing tracks whilst on a random route can help situational awareness in case you need to execute a contingency procedure.
Reviewing the date, effective Zulu time and Track Message Identifier (TMI) ensures fa current track message. Also be aware that the daily track message can change so have an operational procedure to receive the new message.
For Weather Analysis, look at enroute temperature and turbulence forecasts as well as diversion/emergency airport weather, volcanic activity, magnetic storms, and solar flares affecting the route of flight.
Verifying the accuracy of the LRNS is an important step once airborne so the checklist recommends reviewing possible navigation aids for an accuracy check prior to coast out. This planning may help to identify navigation aids that are limited or NOTAMed unusable and is helpful when departing airports close to oceanic airspace.
In the Cockpit
It is a requirement to have a master clock on board synchronized to UTC or GPS. This time source, which is typically the Flight Management System, must be used for all ETAs and ATAs. The use of multiple time sources on the aircraft has led to inconsistencies in reporting times to ATC and resulted in a loss of longitudinal separation.
- Check the Journey Log or Aircraft logbook.
Before entering a special area of operation, crews should focus on any write-ups that affect communication, navigation, surveillance, ETOPS, or RVSM requirements. Any discrepancies noted in the maintenance log or during the walk-around may require a new plan.
Speaking of RVSM, required equipment includes two primary independent altimetry sources, one altitude alert system and one automatic altitude control system. In most cases a functioning transponder that can be linked to the primary altimetry source is also required. Crews should note any issues that can affect accurate altimetry.
- Altimeter checks before taxi
Crews should set their altimeters to the airport QNH. Both primary altimeters must agree within ± 75 feet of field elevation. The two primary altimeters must also agree within the limits noted in the aircraft operating manual.
- Flight plan
The document designated as the Master Document should be carefully checked for date, type aircraft, fuel load and performance requirements. Crosschecks should also be done for routing and forecast groundspeeds. The Master Document should be carefully checked against the filed flight plan to ensure the routing agrees with both documents.
The enroute time should be compared against the total distance for a reasonable groundspeed. The enroute time should also be compared against the total distance for a reasonable fuel load.
Speaking of fuel, where I work, we check the operation of the cross-feed valve and verify the circuit breaker has not popped after checking that the valve operates correctly.
An HF check should be conducted on the primary and secondary HF radios in areas where dual HF radios are required. If possible, the HF checks should be done on the ground or before entering oceanic airspace. Make sure no one is near the HF antennae and listen for the ticking clock sound on 5000, 10,000 etc. You might be able to get your HF assignment on the ground at this point of the preflight on the applicable VHF frequency.
A SELCAL check should also be accomplished at each Oceanic Control Area (OCA) boundary even if you are datalink equipped.
Ensure SATCOM pre-flight complete to comply with FANS/CPDLC requirements.
Both pilots should independently verify the Present Position coordinates using either published ramp coordinates or determine position from the airport diagram. One pilot can read the known coordinates to the other pilot who verifies the FMC as the same.
A master source such as an enroute chart should also be used to confirm accuracy of coordinates at the oceanic boundaries.
This leads into airborne procedures a bit, but Operators are encouraged to use consistent symbols on the Master Document. For example, a circled number means the second crewmember has independently verified the coordinates entered or crosschecked by the first crewmember.
A checkmark may indicate that the track and distances have been confirmed. A diagonal line may indicate that the crew has confirmed the coordinates of the approaching and next waypoint. An X-symbol may indicate having flown overhead the waypoint. We use one slash for waypoint passage and a second slash once the position report has been completed. This results in an ‘X’ over the waypoint. I also start a clock for a ten-minute time reminder to plot the route 10 minutes after waypoint passage to verify we are on the correct track.
Some programming notes: Check the currency of the database. Crews should note if the database is projected to expire during their trip. MELs may allow relief to fly with an expired database but require the crews to manually crosscheck all data. The software version of the database should also be confirmed in case there has been a change.
- Independently verify waypoint entries
It is critical that one crewmember enters waypoint coordinates and that these are independently checked by another crewmember. It should be noted that the pilot should read from the FMS back to the Master Document when verifying data. Reading from the Master Document to the FMS has led to errors based on “seeing what we expect to see” or expectation bias.
Both the pilot loading and the pilot verifying the waypoint coordinates should use an independent means, such as checking the course and distance between waypoints against the Master Document, to verify the accuracy of the route loading.
- Check expanded coordinates of waypoints
Most FMSs allow entering abbreviated oceanic coordinates. There have been cases when there was an error in the expanded waypoint coordinate, but crews only checked the abbreviated coordinate. Verifying only the abbreviated coordinate could lead to a lateral error. In a reduced separation environment such as the North Atlantic, it’s imperative that crews check the expanded coordinates of all oceanic waypoints.
Flight crews should conduct a magnetic course and distance check between waypoints to further verify waypoint coordinates.
- Check course and distance in the oceanic segment
The NAT SPG recommends that crews conduct a magnetic course and distance check from oceanic entry to oceanic exit. Operators should establish a tolerance such as ± 2˚ and ± 2NM. The course and distance check comparing the Master Document against the LRNS are critical in detecting errors that may not have been noticed by simply checking coordinates. A difference of more than 2˚ between waypoints may be due to a difference of the magnetic variation in the database versus the variation used in the Master Document. Any difference outside the ± 2˚ or ± 2NM should be rechecked and verified.
- Uploading winds
LRNS units generally allow the crew to upload projected winds. This procedure allows more accurate reporting of ETAs. Some aircraft upload winds once airborne or enter them manually.
- Groundspeed check
The groundspeed should be noted before taxiing the aircraft. This was a new one for me. The Bulletin says crews should expect the groundspeed to read zero zero knots. The bulletin says that this procedure is a good practice to detect an error that may be developing in the LRNS.
This is a two-part topic so we will talk about the rest of the flight from the taxi phase onward next time. Thanks for listening.
NAT OPS Bulletin 2017-005 issued December 2017
ICAO NAT Document 007 rev2019-3, in section 8.5, pp.79-80.