GPS Approach Options

[Guest RSmith]

Did not receive any comments on my 1st attempt at this question, trying again. (event is re-occuring) Appreciate advice from the "pros" !GPS pre-flight planning, w/loaded IFR flight plan, allows the selection of the apporach procedure (tranisition) prior to departure (approach is "loaded" not "activated"). Transition options are well defined and clear. I select what I "forecast" will be "my" preferred transition, for the conditions, for the active runway I am likely to be assigned.Flight goes according to plan.When I approach the destination, and rececive my 1st descent, vectoring, and approach advisories, I go to my GPS approach procedures, and (intend) to search for the transitional approach that I had previously reviewed and elected, only to find that transition is no longer listed in the approach options ???Todays flight (for example), destination was KTTN. ILS 6 approach was "predicted" - and - in fact was the R/W assignment I received from ATC. Before departure, I had selected the basic "Trenn" transition, ILS 6 approach. (Trenn is located at the NDB FAF).All well - I get the call from ATC to expect vectors to the ILS 6 approach, and I ask ATC to "stand by" - to enable me to go to the approach options, and select the "Trenn" transition approach to that ILS. Once again - it's not there - ??? It's not an option ??Question is: Why are there listed transitions prior to departure - for flight planning - only to have fewer - or missing transitions at approach phase ??Hoping a transport pilot could address - as not sure if this is a FS9 issue, or another oversight by the pilot in command ... (Could be a situation of a private pilot trying to do something he shouldn't be trying !)Thanks for any input.......Ron

[michal 44]

Ron,I don't have direct experience with the 530 unit that FS9 came with but have a lot of experience with the Garmin 530 trainer - and this one works like the real thing.I don't know what exactly happened to you but it is possible the 530 is smart enough to realize that you don't follow any transition (it's too late) and removed all these options. I have no clue. But the right thing for you is when you hear "expect vectors from ATC" to "select vectors to final" from your Garmin choices. It makes liitle sense for you to load "Trenn" if in fact you should be selecting "vectors" instead.If in doubt - dwonload the Garmin trainer (free) and see how the real unit handles such situation. It comes with AP so you can repeat your previous route of flight and compare results.If 530 is in fact clever enough to edit the transition options because of your current position and actions - I haven't see anything of this kind documented in the Garmin manual and I read all the 200 pages of it (twice).If you provide me with your exact route of flight I might quickly verify the scenario on the Garmin trainer and get back to you. Michael J.

[Guest RSmith]

Michael,Thanks for the response !I have been flying different routes, and selecting the various GPS / ILS approach options as practice (GPS approaches with transitions or arc entries - into an ILS). Agree, in "real life", probabilty of a transition approach may be less than a vectors to final offered by ATC. I have no real-world experience in this area.Yesterday's Trenton (Mercer County) flight was long - repeating not necessary (I enoyed a Vancouver, BC, --> Tenton, Mercer County, NJ.) However, for further explanation, my approach (descent) on this flight was initiated around Du Bois, Sate College area, out of FL320 for FL230. Remainder of approach was basic - vectored for a left base, intersection with final (ILS 6) about 17 miles out.I was trying for the TRENN transition after the 1st descent advisory, still more than 75 miles out.... and again, TRENN is at the FAF for ILS 6 - not sure "why" that transition would not be listed...... but admit, not experienced with real-world GPS approaches & options.Thanks for your reply.Ron