In recent years we have had more Koreans mentoring each other. They have friends who are ahead of them in the program, and can tell them what to expect. This has a huge impact.

I'm a firm believer in GIGO. If you treat them like a passenger, then that's what you will get for a year. If you take the time to mentor them, and run things like a real 2 crew environment, you might be surprised what you get.

Occasionally, I get an FO who is either very timid or unmotivated, in which case they may sit on their hands for the rest of the flight, but in most cases I find that they can at least be trained to do an ILS down to their minimum of a mile vis, and communicate with ATC in routine dialogue. In a few cases, I would recommend them to be an AMF captain, but I'd doubt they would take it over a Korean Air 737.