Wow! I've just finished leg 5 of the IVAO DAT 07, the leg to SESM.
If you are the least but of an FS Adventurer, and you've not done the DAT yet, I heartily recommend it to all.
Anyway, as I say I've just finished the leg into SESM, without ever having looked at SESM before, and believe it or not I landed a C182 on rwy 12 first time just by going in with my wits and a sack full o' luck (if you don't know FS's SESM, get a C172/C182 and just have a look)
I've now spent 30 minutes taking off and landing (definitely gets easier with a few attempts) and I've got some tips to pass on:
1. LANDING - approach SESM from RIPAL ISEC directly. DO NOT ATTEMPT TO LAND IMMEDIATELY! Fly over the top of the crater (c.9000ft @Q1013) and have a little recce, the crater consists of two ovoids with a thin point where a road traverses. On the northern side of the crater the road emerges at a low point in the crater wall- this is the place to enter the crater since its the closest to the rwy alt. Descend to about 6000ft (Q1013) and follow the road straight into the crater, at little more than idle throttle (40-50kts), flaps 2, and the moment your radar alt starts climbing as you clear the edge, nose down to about 10deg down angle (more if you feel really confident, and deffo wind the pitch trim to make this comfortable), completely idle the throttle and full flaps. Now follow the wall of the crater in a clockwise direction, turning at approx the major bank angle marker (more if needed, stuff the penalties...), following the wall and descending to just past the extension of rwy 12 threshold to the wall (you should be a little under 1000AGL), now throttle up a little, arrest the descent to normal appr descent, but turn REALLY hard to line up rwy 12 - land

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2. TAKEOFF - is much harder as you're fighting gravity... full length of rwy 12, flaps 2, full throttle on the parking brake until the plane starts pulling away, then brake off and let the speed build - c.50 kts (C182) pull back and pitch up about 8-9 degrees (you should, with luck, maintain 60kts airspeed) and begin circle climbing in an anti-clockwise direction. Theres a "partition wall" in the western end (northern side) that is d**n close the first time around, but it pulls away to the north as you gain height, but you might need to pull a 45deg+ bank on the first (and possibly second) circuit to avoid it. It took me three full circuits of the crater at that attitude to gain sufficient height to safely leave by the low point in the crater wall (where the road is).