Korean Air Flight 8509 Crash at Stansted (HL7451)

Arrival and Maintenance at Stansted Boeing 747 HL-7451 arrived at Stansted at 15:05 from Tashkent. The flight engineer recorded in the Technical Log that the captain's Attitude Director Indicator (ADI) was unreliable in roll and verbally informed the operator's ground engineer. During turnover, repair work was performed on the ADI. Cargo was offloaded and reloaded for the flight to Milan-Malpensa, with a takeoff weight of 548,352 lb including 68,300 lb of fuel. A new crew boarded the aircraft. ## Departure and Initial Climb After a one-hour delay due to ATC not receiving the flight plan, Flight 8509 was cleared to depart Stand Alpha 6 and taxi to the runway 23 holding point at 18:25. At 18:36, KAL 8509 was cleared for takeoff with a reported surface wind of 190 degrees at 18 knots. The Dover 6R Standard Instrument Departure required a climb ahead to 1.5 miles DME, followed by a left turn onto the 158 inbound radial to the Detling VOR. ## Comparator Warnings and Loss of Control While climbing through 900 feet, the ADI 'Comparator' buzzer sounded three times. Shortly after, it sounded two more times as the captain expressed concerns about his DME indication. At 1,400 feet, ATC instructed the crew to contact London Control. As the captain initiated the procedure turn to the left, the comparator warning sounded approximately nine more times. The aircraft reached a maximum altitude of 2,532 feet above mean sea level before banking progressively to the left and entering a descent. It struck the ground with an approximate 40-degree nose-down pitch and 90-degree left bank at a speed estimated between 250 and 300 knots.