Thanks Mace for your answer aboveto further the discussion, if you have problems then it is best to understand what the @ was for.Lets keep in mind that TTools designed by Lee Swordy was originally for FS2002. You should read the Documentation for a full understanding of how the @ back times and locks the arrival time in a FP.Many Many FP developers continue to this day to use TTools for generating FP's and locking arrival times. When FS9 was released we copied our TTool FP's from FS2002 over to FS9. The first thing that happened were few arrivals to a airport and AI Planes started just popping up at the Gate.It took many months to unravel the mystery and MRAI was the first to release a statement on how they were going to handle the problem.You can read about that at their original web sitehttp://www.ahhnet.com/mrai/few_arrivals_solution.phpNow comes FSX and the same thing is happening all over again. Many are just coping over FS9 FP's (without regard to @ or aircraft.txt speeds) made with TTools into FSX or making their own without past knowledge on why TTool FP's for FS2002 do not always work properly in both FS2004/FSX.As an example, WOAI FP developers use TTools for their development of FP's but insure that the Aircraft.txt speeds are set to IAS because they use the @ symbol for fixed arrival times. This is the only way (when using TTools) to be sure all AI Planes fly to the airport rather then just popup at the Gate. Some Payware FP developers took the source code of TTools and reworked it and some Payware use the TDBB for their FP's.

>>AC#9327,220,"US Airways Embraer 190">>>>Yes that is the speed required which resembles IAS that must>be used when @ is present.>>why so? to me it looks much lesser than the cruise speedIn FS2002 the cruise speed setting in the aircraft.cfg file and used in creating AI flight plans was KIAS - Knots Indicated Air Speed. For a jet cruising at FL330 with no winds covering the ground at about 550 knots per hour - that would about 300 knots indicated air speed (I know it's not exact - just as an example).In FS2004 the cruise speed in the aircraft.cfg file and in creating AI flight plans was changed to KTAS - Knots True Air Speed. That is approximately the speed over the ground with no winds. That's not the exact definition, but close enough for discussing FS AI flight plans.That is still the case in FSX.However, almost nobody creates flight plans for AI traffic using the Microsoft Traffic Database Builder tool - where using those speeds works correctly. Certainly no one doing individual airline flight plans trying to match real world schedules.The cruise speed in the aircraft.txt listed above is ONLY used in calculating the location of the AI aircraft at specific times during the flight path. It has absolutely no impact when the AI aircraft is flying.There is a serious timing issue between TrafficTools created flight plans with set arrival times (the @ symbol) and FS2004's AI aircraft generation/ operation cycles. The same appears to be the case in FSX.What happens is that the location placement of the AI aircraft in the TrafficTools created scenery file is not understandable by FS, so FS2004 and FSX will not create the aircraft in the air and allow it to approach and land.Rather FS2004 and FSX create the aircraft on the ground at the gate for it's next flight leg.The 'fix' is a bandaid which does not address the root cause of the problem. But it does work for most people, and a key rule in FS is what every works on YOUR COMPUTER is the way to go.