Date: 201202
Local time of day: 0001-0600
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Weather elements / visibility: 15
Light: Dusk
Aircraft: Citation Excel (C560XL)
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class E ZZZ
ATC / advisory: Center ZZZ
Aircraft component: FMS/FMC
Component problem: Improperly Operated; Design
Reporter organization: Air Taxi
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Air Traffic Control Fully Certified; Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor
Human factors: Distraction; Human-Machine Interface; Situational Awareness; Confusion; Training / Qualification; Time Pressure
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew; Person Air Traffic Control
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Human Factors; Procedure; Manuals; Aircraft
Primary problem: Ambiguous

Narrative: I would like to start with the fact that I believe this incident report is not a result of low time in the aircraft type; as it is with low time with this particular FMS. This is our second aircraft of the same type; but it has a different brand of FMS on-board. The new aircraft's FMS is a Honeywell FMZ FMS with NZ 5.9 software. Our other same type aircraft has Universal Avionics Systems Corporation FMS that we have MANY hours in between this type aircraft; and other aircraft types as well. When we first received the Honeywell equipped aircraft; it was VERY clear to us that that we were not going to be able to fly the aircraft until we had some training on it with the aircraft ON THE GROUND. There was NO WAY that we were going to be able to 'Wing it' with the new (to us) Honeywell FMS. This FMS is NOT intuitive at all. It is NOT menu driven. It requires the operator to learn what I call; Honeywell's special FMS 'shorthand' to enter information into it. Information is difficult to obtain from it; many page selections are required to get often used information. The Honeywell FMS does not even display estimated aircraft weight at destination; something that we need to enter arriving V speeds. We were inbound on the STAR. We thoroughly checked what was loaded into the FMS was what was on the paper chart; altitudes and all. When we were en-route from a VOR the Center Controller cut a corner short for us (he initiated it; not us) by issuing: Proceed direct to an arrival intersection; cross at and maintain 11;000 FT. We selected direct the intersection on lateral navigation and looked at the FMS to verify that 11;000 was already entered for the intersection. The FMS was already set to fly in VNAV mode for the descent; so we 'thought' that it would take us vertically to the first constraint in the STAR at 11;000. We were wrong. The FMS was taking us down but; to this moment; I still can not tell you where it was taking us vertically. We were about four miles from the intersection when we realized that we weren't going to make the 11;000 restriction. We already had the speed brakes out; creating a disturbing a ride for the passengers at that speed; when the controller started on us about the 11;000 FT restriction and that he had traffic off our left near our altitude. I don't know if there was a loss of separation operational error or not. There was no TCAS RA/TA event. I would like to add that we obtained Honeywell's PC-FMS training software BEFORE taking possession of the new aircraft that had the Honeywell FMS. I specifically had trouble with the training software with regard to running VNAV operations. The next two paragraphs contain my question to Honeywell and their response. Reporter: 'Also; I don't seem to be able to get the 'FLYING' aircraft to follow the VNAV even with the V-NAV feature enabled underneath the map display. It does follow the altitude command. But if I set it to 200 FT while the aircraft is outside the FAF; it will just fly into the ground ignoring all of the VNAV restrictions along the flight plan. So I don't know if I am wrong with the VNAV entries in the flight plan. Honeywell's response:  'VNAV features in the free play (simulation) are a simplistic representation not a full functional simulation. I don't think there is anything wrong with your VNAV entries.' It is not for lack of effort on our part in trying to learn the new FMS.




Synopsis: A CE560XL Captain reported the aircraft's FMS missed a crossing restriction because the Company's newly acquired aircraft's Honeywell FMS VNAV did not respond like the Company's original aircraft's Universal FMS.