HI Altitude test
Yeah!, you right 12000-15000ft is Not a REALLY high Alt .
But consider that you have to stay in still in HOGE (or very little speed) for about 20 minutes at the time.
They have to drop a special device with a long rope (like a hoist ops.) with a special winch, that's why a Mil Mi8, because has a nice Hole opening inside the fuselage.
They have to do that in Marocco cause' the terrain looks like Mars.
But it seems difficult to find a civilian Mil closeby, a of lot of those in Russia, CZ, Bulgaria but not Marocco.