You fly a SF340 and claim an A310 is underpowered? I have about waaaay more than enough SF340 time to know that if anything is underpowered, it's the 'SLOB'-340. The only time I've seen an A310 act like a SF340 is on a 120+ degree day fully bagged out in DXB - and then it still performs reasonably well.

My guess to the answer of the original question is also the 10kt limitation for 90 degree turns - it probably looks like a full stop but it really isn't.