Korean/asiana airlines pilots were banned for 12 mos by the airport authority where i worked over a decade ago pending pilot training and english review due to numerous incidents of pilot error and communications problems. Those two airlines managed to ram the jetway 3 times, and even rammed the maint hanger causing millions in damage. One pilot tried to take off with the fuel truck still attached, one pilot had poor english ordering fuel be halfed instead of extra fuel and had to fly back because the pilot only noticed 1hr after takeoff, and two (yes, two) Korean reg'd AC tried to land on the highway instead of the runway.
Another Korean air flight misunderstood the tower and tried to land at the same time as an another plane almost causing a crash, which was only noticed by the other pilot who got out of there. I was there when they asked the pilot about it who was completely clueless he had almost killed everybody on both flights.
I dont know whats up with Korean pilot training but talk to anybody who has worked in a tower and they will tell you horror stories. Theres also the 911 incident where they broadcasted a hijack code for some reason and were almost shot down over the Yukon.