Anchorage International Airport
Aircraft Accident/Incident Report

Anchorage, Alaska 99502
Thursday, May 16, 1996 6:33 AKD

MD-11 was cleared visual approach (apch) to runway (rwy) 24R, 3 mi (1 min) behind Boeing 747 (landing on rwy 24L). Rwys were 550 ft apart with rwy 24L threshold staggered 4300 ft beyond that of rwy 24R. MD-11 captain (capt) used VASI, which had 3.25 deg glide path. On final apch, 21 kt left crosswind diminished to about 5 kts. From 100 ft agl, MD-11 exhibited left, then right roll & slight yawing. About 50 ft agl, MD-11 entered high sink rate. Capt began go-around & raised nose. Lower aft fuselage hit rwy & MD-11 bounced. Capt discontinued go-around; MD-11 bounced two more times; sustained damage to aft pressure bulkhead. Last 20 sec of flight, MD-11 averaged 1380 ft/min rate of descent, 152 kts, 5.12 deg apch angle. MD-11 flight manual discussed visual apchs, go-around procedure, & tail/wing clearance issues, but operator did not have formal tailstrike awareness training for MD-11 pilots. After accident, operator developed tail strike awareness training program that included bounced landing recovery & simulator training, & limited pitch attitude to 7-1/2 deg for recovery from bounced landing. AIM recommended that for landing behind larger acft on parallel rwy, closer than 2500 ft, stay above larger acft's flight path. Tower controller did not issue precaution for wake turbulence.

the pilot's improper in-flight planning/decision, which allowed the airplane (MD-11) to encounter wake turbulence from a larger/heavy jet airplane (Boeing 747), while on a short final approach for landing on a close-by/parallel runway with a staggered threshold. Factors relating to the accident were the staggered/off-set runway thresholds, which positioned the normal approach path of runway 24R below that of runway 24L; the steeper than normal final approach path; and the left crosswind, which resulted in wake turbulence drifting from the Boeing 747's approach path to the MD-11's approach path.