Flight Levels in North Atlantic Tracks

[dmwalker 604]

I have been following BAW9L from EGLL to CYYZ and I have noticed on three occasions, FlightRadar24 shows it increasing its altitude by 1000ft at some point along the North Atlantic Track.

I have always understood that, when you enter a track, you can't change your altitude or speed until you have exited the other end. Is that not always so or is FlightRadar24 just giving some anomalous readings?

[Bob Scott 7,721]

Sure you can--you just have to get clearance from ARINC (via Gander/Shanwick/ACARS) to do it.  Obviously whether you'll get clearance depends on whether there's traffic near you on the level above.  The NATS are really busy at times, so it's not something you can count on for your fuel planning.

[Dave_YVR 973]

You can request another altitude with ATC and if it's available, they'll give it to you.

[jon b 2,047]

it certainly used to be a bit more rigid, but capacity and flexibility have increased with performance based navigation and more tracks being introduced.
There are some relatively new CPDLC message sets and procedures that have been brought in , these included the messages”SHANWICK ADVISES HIGHER LEVEL MAY BE AVAILABLE IF REQUESTED’ and my favourite “ RESUME NORMAL SPEED”

As ECON is quite often faster than the planned fixed Mach number this saves time and often fuel. So after receiving the resume normal speed message you can delete the fixed Mach number and cruise at ECON or anything else you fancy , you only need to tell oceanic if your new speed differs from your original cleared speed by +/- M.02.

Edited April 11, 2022 by jon b