Originally Posted by
josephfeatherweight
Australia is the only country in the world that imposes this “cross WAYPT at XX”, with the “up to 30 secs early, but not late” thrown in for good measure. I fly what would be considered a modern aircraft and the FMS has no function to readily assist with achieving these requirements - in fact, it actually throws you under the bus because the FMS displayed estimated time over a waypoint is usually about 3-4 mins later than the time you actually end up flying over it - the discrepancy appears to magically fix itself when you’ve got about 3-4 mins to run and no chance to fix it. This is not a case of unaccounted descent winds. Of course, we are aware of this and I usually just get the old whizwheel out to sort it out and achieve the requirement.
Everywhere else the the world, even where it is actually busy (eg New York), ATC just tell you what speed to fly and it all works out. What is especially frustrating is flying across the Bight at max chickens for 3.5 hours to then be required to “reduce speed to cross BVRLY at XX” - we’ve got ADSB/CPDLC - you can see where we are and what we’re doing...
By the way, I blame the system, NOT the controllers.
So, long story short, even relatively modern aircraft don’t necessarily have a function that assists with this issue.
(Other than distance to run and ground speed!)
Don’t know what you’re flying, but the Honeywell FMS that’s standard in most Australian buses will give you an estimate based on the current conditions to the second in which you will pass overhead the feeder fix. It’ll need a bit of managing as the conditions change, especially on the way down, but if you can’t cross the waypoint within 5 seconds of what you require, you shouldn’t be sitting in the seat.