Originally Posted by
Propellerhead
Also, how likely are you to actually divert? If the weather at destination is fine and there’s multiple runways I’d be less likely to take extra fuel for avoiding CBs en-route etc as I know I can likely dispense with the alternate (and probably get a direct routing after weather avoidance). If it’s a single runway, with no ILS in the Caribbean, I would be more cautious.
That’s the way I look at it. Also, the planned remainder is worth taking note of as that shows how much holding time you will have if you do commit to destination; sometimes that can be considerable if the alternate is a fair distance away for commercial/political reasons, so you can absorb significant delays without needing any extra fuel.
Looking back through my logbook, the most common cause of diversion has been medical followed by airspace closures. I can’t remember the last time I had to go somewhere else through lack of fuel at destination and I rarely take any extra.