Date: 201702
Local time of day: 1201-1800
Location: TMB.Airport, FL
Flight conditions: VMC
Weather elements / visibility: Cloudy; 10
Light: Daylight
Aircraft: Citation V/Ultra/Encore (C560)
Operator: Corporate
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class E MIA
ATC / advisory: TRACON MIA
Reporter organization: Corporate
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Human factors: Human-Machine Interface; Situational Awareness; Workload
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Procedure; Human Factors
Primary problem: Procedure

Narrative: To fully understand what follows; the reader will need to refer to the following aeronautical publications for the TMB (Miami Executive) airport:1) SSCOT THREE Arrival2) ILS 9RWe were making our descent into the Miami terminal area via the SSCOT3. On the TMB ATIS the tower was advertising visual approaches to runway 9R. We set up our avionics for the ILS 9R as is our normal procedure. This setup included loading the ILS approach into the FMS FPL (Flight Plan) from the database. In the vicinity of the SSCOT intersection; Miami Approach instructed us to 'proceed direct to the EYAXO intersection.' After pressing the DTO (Direct To) key on the FMS; I discovered that the EYAXO intersection was not in the list of available waypoints. We queried the controller about the phonetic spelling of the waypoint and he advised us that it is on the approach chart. On the Jeppesen chart; where the procedure turn rejoins the final approach course; I saw the waypoint.  However; it is a fly-by waypoint depicted within brackets; i.e. [EYAXO] and the font is smaller than that of the principal fixes on the chart. After much searching; I am unable to find any specific information regarding this depiction of a waypoint or whether it ought to be used for air traffic control; but I digress.We continued to fly our previous heading (120 degrees) and I advised the controller that the waypoint is 'not in our (FMS) flight plan' while I was manually entering the waypoint into the FMS; It was about this time that the controller; who was now annoyed by our apparent incompetence; began to give us radar vectors toward the waypoint. We were probably within 5 NM of EYAXO by the time we reprogrammed the FMS and were able to fly directly to the assigned fix. All of this brings me to the purpose of my report. First; while RNAV is a beneficial tool for pilots and controllers alike; it has its limitations. In this situation; when the controller learned that we were unfamiliar with intersection; he should have (1) immediately issued a radar vector toward the intersection; or better; (2) abandoned the use of that intersection altogether and issued radar vectors to the final approach course. Second; it is my assertion that this particular waypoint should only be used for air traffic control when it is requested by the pilot. This fix is not a relevant part of the straight-in ILS approach. Its purpose is to enable the pilot to use the FMS; in conjunction with the autopilot/flight director; to fly the course reversal (procedure turn); nothing more.  Moreover; there are a number of problems associated with making modifications to an approach that has been inserted into the FMS flight plan from the database. In many cases this is impermissible and the remaining waypoints will be automatically deleted or the approach cannot be activated. Third; I am convinced that the controller believes he was 'helping' us when he issued the clearance to proceed direct to EYAXO. I also suspect he is entirely unaware that; in fact; his clearance created confusion in the cockpit; distracted us from our other duties; and increased our cockpit workload at a time when it is already quite high. His use of that intersection for the purpose of air traffic control was not only unwise; but also it was wholly unnecessary given the situation. While descending into high density airspace; we were put into a situation where both pilots are initially distracted from our principal duties and one pilot is necessarily 'heads down' in the cockpit reprogramming the FMS instead of looking outside for threats that doubtless exist. All this potentially dangerous rigmarole could have easily been avoided by the informed use of RNAV by ATC. Also; I think this specific situation ought to be investigated using other avionics equipment to determine whether the same or similar problems arise.In retrospect; we should have simply requested a vector to final.  That would have immediately eliminated all the hullabaloo and high blood. However; in our effort [to] be good little pilots and to dutifully comply with ATC instructions; we merely added another link or two to that insidious chain that so often leads to an avoidable accident. Another valuable lesson has been learned.




Synopsis: CE560 Captain reported confusion and high workload resulted from an ATC clearance to a point that was not part of the ILS in their FMS.