North Atlantic Clearance/RCL Max Flight Level
 

Hello,

NAT 007 says to include a free text message in your RCL/Oceanic clearance request indicating maximum acceptable flight level using the format: MAX F330 , MAX F340 etc (just F, not FL).

My question is, does an automated system pick up on this text, and, if entered properly preclude you from being cleared above your stated max? To expand on that, is there a specific reason why you should write F350 and not FL350 other than "because they said so"?

A colleague asked me these questions recently. I didn't know the answers for certain, although I am inclined to think that there is/was no automation looking at this because I have been issued a NAT clearance above my stated max level. I had to reject the clearance and request a new one with a lower altitude, so I speculate that the max is something that a human must notice when issuing the clearance, or might not notice. Does anyone know?

F is the ICAO standard notation for flight level as used in flight plan submission. Perhaps that’s the reason?