"Unable Cruise Alt" Collins FMS 6000
Attention all FMS Performance Guru's !!
Has any Collins FMS 6000 operators found problems with the predicted climb performance/cruise alt of their FMS ?
In my case our HS125-800 FMS generates an "Unable Cruise Alt" msg on a regular basis. The main problem is that the Flight manual Cruise Alt V's Weight charts, for the same weight/flight level and ISA deviation don't seem to match with the FMS msg warning. What am I missing Here ??
When the FMS is calculating the Performane Cruise Ceiling, is it only concerned with Flight Manual Ceiling limitations or is it also looking at buffet boundary ?
Should I observe the FMS warning and select lower levels or select levels with respect to the Flight manual charts and ignore the FMS warning ?
Any input much appreciated.