Database Coding and FMS Behaviour for VPT (prescribed visual flight track) procedures
There are some offset non-precision approaches that require a prescribed visually flown flight track from tha MAPt/Minimum to the runway, Nice being a prominent example.
I'd be keen to know how different FMS/databases handle this when the approach is flown using the FMS.
With a database coded like most other approaches, i.e. a missed approach following after the MAPt, "my" Honeywell FMS will sequence from the MAPt to the runway if no missed approach is performed, thereby giving an immediate turn command after the (fly-over) MAPt where continued straight flight would be required (until intercepting the runway centerline).
Now I do fully understand that the visual part should not be flown using FMS guidance but this requires a "split second" disengage of the FMS (as it should not be disengaged before the MAPt to allow flying the MisAP with FMS guidance if there's no contact but cannot be disenganged after the MAPt without entering a turn toward the runway).
IMHO it could also be corrected by entering a "heading" / "vectors" type leg after the MAPt or leaving a discontinuity that will result in the A/C maintaining the last track/heading which our database provider seems to consider against the rules.
A quick web search didn't leave me with any clues about coding standards for situations like this.
Any input on existing coding standards or simply practice on various A/C would be helpful.
Thanks!