Journey Man
6th Aug 2022, 01:31
Hi,
I have read some threads here that ask about specific aircraft type FMC behaviour towards speed constraints, but I have not seen a regulatory reference on how this should be approached.
On my aircraft with a Honeywell avionics suite, a speed constraint in climb is treated as applying "before" the waypoint, which makes sense as generally we are accelerating. In the cruise and descent the speed constraint is respected by the FMC from the waypoint the speed constraint is coded to, rather than at or by the waypoint. I have always treated intermediate speed constraints, in both conditions of acceleration and deceleration, as applying at the waypoint, so in descent I would need to intervene on my aircraft and proactively manage the speed (and possibly descent profile) to meet the constraint limit.
I've had a look through various regulatory sources I can think of, but can't find anything definitive as to how intermediate speed constraints should be respected. Admittedly, I'm not sure what the best place to find this reference would be. - especially a more global reference and appreciate this may differ from state to state.
Does anyone have a good source they could share?
Thanks in advance.
I have read some threads here that ask about specific aircraft type FMC behaviour towards speed constraints, but I have not seen a regulatory reference on how this should be approached.
On my aircraft with a Honeywell avionics suite, a speed constraint in climb is treated as applying "before" the waypoint, which makes sense as generally we are accelerating. In the cruise and descent the speed constraint is respected by the FMC from the waypoint the speed constraint is coded to, rather than at or by the waypoint. I have always treated intermediate speed constraints, in both conditions of acceleration and deceleration, as applying at the waypoint, so in descent I would need to intervene on my aircraft and proactively manage the speed (and possibly descent profile) to meet the constraint limit.
I've had a look through various regulatory sources I can think of, but can't find anything definitive as to how intermediate speed constraints should be respected. Admittedly, I'm not sure what the best place to find this reference would be. - especially a more global reference and appreciate this may differ from state to state.
Does anyone have a good source they could share?
Thanks in advance.