I have been practicing using the FMC with the captain sim 757, flying from tampa to maimi, and I notice that most of the takeoffs and approaches add about 190 NM to a flight that is only 200 NM at the most with a straight shot, so i always seem to be flying for over 2 hours in a flight that should take less than, am I doing something wrong?

If you are using the SIDS and STARS they will add milage, try using just 'High Altitude' airways from the FS built in flight planner.

Did you check the waypoints and their distances on the "LEGS" page?190+ seems a bit too far for just some SIDs and STARs. Maybe you've added some points twice and it calculates a "back and forth" of waypoints. Or you've chosen an arrival which doesn't fit to the direction you're approaching from.

Depends on ATC a lot of the time, and how you plan your flight too of course. By way of example, here's the SID for the MONTY/NOKIN departures from my local airport, Manchester. These are the SIDs that gets used when the wind is not blowing in its more normal direction from approximately 240 degrees, when SIDs from R23 would instead be used. For these departures, one would expect a wind from the East:You can see that the chart tells you the average track for the departure routes is about 60-70 miles, but of that, probably half of the distance would be in the direction the aircraft wanted to go, for example, flying to Spain or France. So of course you would use a departure that pointed you the right way. Sometimes, ATC would allow an aircraft to route direct and not have to fly all of the SID route if traffic allowed, so an aircraft might be halfway to the Wallasey VOR and get told it can turn direct for its next major routing waypoint, since the controller is often aware of exactly what that route is, especially for regular scheduled flights.The same is often true of STARs, where a controller might allow an aircraft to cut a few corners if there isn't much traffic and the terrain clearances are okay, however, not all airline pilots are keen on doing that sort of thing, since flying unpublished routings can throw a spanner in the works when the instruments are all set up for an expected route, and sudden changes to a route have occasionally led to accidents. Such as on this occasion, for example: http://www.aaib.gov.uk/cms_resources.cfm?f...81%20G-BDAN.pdfIn any case, two hundred miles is a pretty short flight for a 757; that's more the kind of territory that an ATR-72 or smaller jet might fly, so it is perhaps a bit of an unusual example to try full-on SIDS and STARs on. But it's not unknown for airliners to fly another few hundred miles to get around or make use of the weather though, so some extra mileage isn't actually terribly unusual. With the kind of speeds jets fly at, it could be a case of simply an additional 20 minutes, and much of the time, a SID or STAR will be used because of the favourable winds it confers for a large portion of the flight. You can see that in the above SID chart - the westbound portion of the track before the aircraft turns south will probably have a good tailwind, since the aircraft will have departed from the runway into the wind. Large aircraft departing from Europe for the United States can occasionally fly as far north as Scotland to get a favourable tailwind before turning West to head across the Atlantic!Al

KTPA-KMIAGANDY3 SABEE CYY SSCOT1280nm ~50 minutesMake sure youre selecting the correct Sids and Stars as well as using a good route. For really short flights sometimes SIDs or STARs are not used in real life.

SIDS and STARS are meant to simplify and expedite, without the need for extraneous ATC comm, arrivals and depatures for generally speaking, much longer legs than Tampa --> Miami. It's highly likely that on that short route in most aircraft going greater than 250 kts, a few simple radar headings would be used guiding you to a Nav fix on your route or even right up to the IAF of the arrival airport.In fact, in RL, I've gotten radar vectors up and down very large chunks of the coast in a slow helicopter. Easier for them to keep me out of their way doing that :)

For really short flights sometimes SIDs or STARs are not used in real life.

Not necessarily true worldwide. A flight of just 22 minutes in a jet aircraft, here in Colombia, has SID and STAR. Now, they might not be flown completely by means of "direct-to's" or radar vectors, but they're there and you're planned to fly those.Examples include (for those interested): SKBO-SKRG (and back) SKRG-SKCL. Those two don't take more than half hour.As to the OP's question, I would say check your routing. That includes SID and STAR as others have mentioned and also your waypoints. Try to cross-check them to a real world flight plan on some site like flightaware.com. You guys get great coverage in the States on that site.Also check your approach facility used, since different approach types might have different routings too; an ILS approach may be shorter/longer than a VOR, for example.Oh, and don't worry for 10NM, no biggie. Start to doubt about things when you have +30 or 40NM offsets.

Not necessarily true worldwide. A flight of just 22 minutes in a jet aircraft, here in Colombia, has SID and STAR. Now, they might not be flown completely by means of "direct-to's" or radar vectors, but they're there and you're planned to fly those.

In the UK, if an airport has published SIDs, ATS won't accept a flight plan that doesn't use them. Also, SIDs reflect Noise Preferential Routings. As a result ATC will not generally divert aircraft from a SID below 4000'.