United Airlines Flight 345

On July 29, 2014, about 2240 pacific daylight time, United Airlines flight 345, a Boeing 757-222, N553UA, experienced a tailstrike while landing at the San Diego International Airport (SAN), San Diego, California. There were no injuries to the 174 persons onboard. The airplane sustained substantial damage. The flight was operating under 14 Code of Federal Regulations Part 121 as a regularly scheduled passenger flight from George Bush Intercontinental Airport (IAH), Houston, Texas, to SAN.

According to the operator, the first officer (FO) was the pilot flying and the captain was the pilot monitoring. The accident flight was the second flight of the day for both crew members. The climb, cruise, and descent portions of the flight were uneventful. The airplane was configured for a flaps 30 landing with the autopilot off for the visual approach to runway 27. The target airspeed for the landing was 130 knots, 5 knots above VREF.

An airplane performance study was completed based on the FDR data from the flight. The study showed the wind was constant during the final descent to the runway with about a 4-knot headwind component. At about 50 feet radio altitude, the FO began to gradually pull back on the column until the elevators deflected 12 degrees airplane nose up at touchdown. Touchdown occurred with a sink rate near 0, a pitch attitude of about 6 degrees and an airspeed of 120 knots (5 knots below VREF). After touchdown, thrust was commanded to idle and the speedbrakes were deployed. The FO then began to gradually release column backpressure; however, pitch attitude continued to increase towards the gear-struts-compressed tail strike pitch attitude. The airplane's pitch attitude eventually exceeded the gear struts compressed tail strike attitude of 10.5 degrees. The FO commanded reverse thrust as the tail strike occurred and then increased to maximum reverse thrust after derotation had occurred.

Published Flight Operations Technical Bulletins issued by the manufacturer in 1988 and 1990 instructed pilots to immediately lower the nose after touchdown (i.e. apply forward pressure) and warned pilots that bleeding off airspeed below VREF prior to touchdown will increase body attitude and thereby increase the likelihood of a tail strike. In this accident, touchdown occurred about 5 knots below VREF and the nose-up elevator remained for nearly 3.5 seconds, causing the aft fuselage to contact the runway.

Inspection of the airplane revealed substantial abrasion damage to two aft, lower skin panels spanning an area about 4 feet long by 1.5 feet wide. In addition, the forward and aft lower chords on the aft pressure bulkhead (APB) were deformed and the lower APB web was buckled.

Verbatim NTSB analysis and probable cause from the NTSB dataset