If flying with GPS, when do I have to activate the approach procedure? I know that I need to allow the plane time to descent to the proper altitude, but at what distance to the destination should I activate the approach procedure? Another question is. Should I descent to lower altitude before activating the approach procedure or start descenting while the approach procedure is being executed?

BOPrey,There really isn't a simple answer to any of your questions...but I'll give it a shot.1. When do you activate the approach procedure in the GPS? When you're cleared for that approach by ATC. Exactly when depends on the ATC program you're using for FS9. The default ATC will start giving you vectors as far as 75 or 80 miles out, so you'll never have the chance to activate that GPS approach. Radar Contact gives you the option to request a particular approach when you get handed off to Approach Control. On VATSIM, it really depends on the workload of the controller, who may want you to deviate from the published approach for sequencing or as a courtesy to you, to expedite your flight.2. How far from the destination should you activate the approach procedure? As you get near the transition if it's a STAR, and as you near the Initial Approach Fix (IAF) for a runway approach.3. Should you start your descent before activating the procedure or start descending while the approach procedure is being executed? That depends on your cruise altitude and the procedure being used. Many STARs have crossing restrictions (waypoints that must be crossed at a particular altitude) and pretty much all runway approaches have crossing restrictions. Here again, you're dependent on ATC for the start of your descent. If you're IFR, you can't start down until you're cleared to do so. A good rule of thumb is to subtract the desired altitude from the present altitude and multiply the difference (in thousands) by 3 to get the distance for starting your descent in nautical miles. Then, multiply your ground speed by 5 to get the descent rate.For example, you're flying a King Air at FL200 and need to cross the IAF at or above 6,600 feet. Your ground speed is a healthy 285 knots. 20,000 - 6,600 = 13,400, so you need to start your descent a little further than 40 miles out, and descend at between 1400 and 1500 feet per minute. In a case like that, I'd start asking ATC for a lower altitude about 50 miles out, to give the controller some time to think about how your request affects his airspace and respond.Hope this helps!

The default ATC will start giving you vectors as far as 75 or 80 miles outThe vectors approach is the novice mode MS built into FS for people who do not understand, or wish to use real world procedures.I load the approach I wish to fly before I take-off, after receiving my ILS clearance. Always choose an approach with a transition. I do not activate it, because like the real world - the weather and traffic can change my plans.When the ATC attempts to assign a novice approach, tell it to wait and choose the approach you wish to fly.The ATC will clear you to the transition waypoint, or the IAF. It will also tell you when to descend.At that point - Activate the approach on the GPS - and it will fly the approach as well as the fanciest, most expensive addon aircraft FMS, except you will have to control the descent.It is useful to have the STAR and approach charts so you know the optimal altitudes.FS2004 only has altitude setting targets for approaches - not enroute STAR waypoints. You may need to request a lower altitude from the ATC for some of those.

Agreed. Before arriving at terminal area, determine the approach and transition you want. When ATC tells you to turn/descend, select the "standby" responds, and then select from atc menu the runway, approach, and transition, then request it from ATC. ATC will normally tell you to expect your requested approach and transition, and clear you direct to the transition fix. At that point you can activate the approach in the GPS, and get a magenta track to follow in the plan view display. Note that you still must abide by any altitude clearance given by ATC. Once ATC clears you for the approach, at that point you may follow the altitude limitations and tracks for each leg of the approach.scott s..