Korean Air Crash:
If the crew did a go-around and failed to position the gear lever from the UP position to OFF as per the checklist, the residual hydraulic pressure would make trying to release the gear from there up-locks impossible. The hydraulic pressure would keep the gear in the retracted position. This procedure is in the After Takeoff/ Go Around checklist and the Maunal Gear Extension checklist. Crew checklist were not run…
Former Boeing Flight Test Engineer/ Retired Captain 737-800