FSAirlines

Curious what the "Tolerance Ratio" is for like aircraft regarding weights.

We know if one is flying 2 engines, that meets a 2 engine aircraft tolerance.
Just curious how far off the weights can be before FSA rejects it.

There is no Cessna Longitude for FSX, but the Citation X works and those weights are fairly close. Also a B738NG is almost identical in weights to the A320Neo so it works as a substitute in FSA too.

From what I've seen FSA won't let you take off if you're over the MTOW, period. So if you're 'close' it'll work.. I did a flight last week in MSFS using the CRJ-550, but using a CRJ-200SF in FSA, about 10,000 lbs difference in the MTOW. I was able to balance the plane to fit within the tolerances (spoiler: wasn't worth it though).

Would be interesting to know about the 'Flagged for Review' though, especially for MSFS since we're so limited in what we can fly there.

The client is looking at the weights (DOW and MTOW) and number of engines. In general it allows the weight of the aircraft to be around 20% of what's defined. The code was originally designed to catch cheaters, so while it won't allow you to go too far below the specs, it does not really care if you go over. So it won't allow you to use a 737 in place of a 777 as it would probably use too little fuel, it does not mind the reverse as the pilot is just costing themselves money.