Here's what I do. This requires a bit of preparation, but does work.
Before you head to the ROK HQ, go to the area south of the steel bridge leading to the AN HQ, but on the west bank of the river. You will find an AN UH-60. Take it and fly it to the ROK HQ.
When you accept the mission, there will be a BJ-2020 scout, a crate and an ROK cargo truck. Move the truck out of the way. Break open the crate. Climb in the UH-60 and use the magnet to winch the BJ-2020.
Now, Climb to 400+ meters and head towards Nampo, but not exactly Nampo. Head for the summit mesa where you destroyed the DPRK communication center for China in their first contract. Set and release the BJ-2020 and land the helo.
Drive the jeep to the airport. Find the guy and get him in. Get out as fast as you can, but, instead of heading down the road towards the ROK HQ, drive back to the where you parked the helo. Transfer to that and fly to the ROK HQ. The yellow circle landing is very tetchy because the helo is not easy to maneuver, but can be done.