The missing data deepens the puzzle of what caused the deadly air disaster in Muan, South Korea, late last month.

Korean investigators' efforts to understand the Jeju Air Boeing 737-800 crash at Muan have suffered a setback after both flight recorders failed to capture the final 4min of the accident sequence. The aircraft overran at high speed,

Flight data and cockpit voice recorders from the Jeju Air flight that crashed at South Korea's Muan International Airport stopped recording four minutes before the tragedy that claimed 179 lives. On December 29,