HISTORY OF FLIGHT On February 12, 2000, about 1346 hours central standard time, Delta Airlines Flight 695, a Boeing 757-232, N671DN, sustained substantial structural damage to the fuselage in the nose wheel area during landing on runway 25 at San Salvador International Airport, San Salvador, El Salvador. Delta Airlines, Inc., was operating the airplane as an international, scheduled, passenger flight under the provisions of 14 CFR Part 121. The airline transport pilot captain, first officer, 6 flight attendants, and 153 passengers were not injured. The flight departed Atlanta, Georgia, about 1134 eastern standard time on a nonstop flight to San Salvador. Visual meteorological conditions prevailed and an IFR flight plan had been filed. The same flight crew flew the airplane back to Atlanta, where another flight crew boarded the airplane and continued on to Los Angeles, California. No discrepancies were reported by either of the flight crews or maintenance personnel in San Salvador and Atlanta. After the airplane arrived in Los Angeles, a post flight walk around inspection by the Delta maintenance department found the outside of the fuselage buckled on the left side above the nose landing gear door. Further examination disclosed that structural members were bent and fractured in the nose wheel well. The crew that landed in El Salvador stated that the nose gear touched down more firmly than the main landing gear. They completed a post flight inspection, but detected no abnormalities. PERSONNEL INFORMATION The captain held an airline transport pilot certificate with an airplane multiengine land rating. He held a first-class medical certificate that was issued on January 17, 2000, with no limitations or waivers. The operator reported he had a total flight time of 25,000 hours. He logged 145 hours in the last 90 days, and 10 in the last 24 hours. He had 6,916 hours in this make and model. The first officer held an airline transport pilot certificate with an airplane multiengine land rating. He held a first-class medical certificate that was issued on February 11, 2000, with no limitations or waivers. The operator reported he had a total flight time of 6,500 hours. He logged 32 hours in the last 90 days, and 10 in the last 24 hours. He had 809 hours in this make and model. AIRCRAFT INFORMATION The airplane was a Boeing 757-232, serial number 25332. The operator reported a total airframe time of 27,934 hours. The airplane was operated on a continuous airworthiness maintenance program and had accumulated 8 hours since the last inspection. The airplane had Pratt and Whitney PW2037RTC engines installed. AIRPORT INFORMATION The operator reported that runway 25 was 10,500 feet long and 148 feet wide. FLIGHT RECORDERS A Lockheed model 209F digital flight data recorder (FDR), serial number 4668, was installed. The recorder was removed and sent to the Safety Board's Vehicle Recorder Laboratory for readout and evaluation. A Safety Board specialist conducted a data comparison for the landings in El Salvador, Atlanta, and Los Angeles, and prepared a factual report, which is attached. A summary of the findings follows. The FDR indicted that, in the El Salvador landing sequence, the air/ground FDR discrete indicated "air" then a second later indicated "ground." A second later it indicated "air" again, and then a second later indicated "ground," and remained "ground" for the remainder of the landing roll out. During this phase, a right roll angle developed, while the pitch angle and control column movements were more pronounced than on the other landings. For the Atlanta and Los Angeles landings, the air/ground discrete indicated "air" then a second later indicated "ground" and remained "ground." In the El Salvador landing sequence, 1.82 seconds after the air/ground discrete indicated "ground" for the last time, the nose gear squat switch indicated "ground" and remained "ground." The data also indicated that the airplane's pitch attitude was approximately 1.9 degrees when the air/ground discrete first indicated "ground." About 1 second later the pitch attitude was 0.7 degrees, and then 1 second later was approximately 0.4 degrees. The data indicated that 23.55 seconds before the air/ground discrete first indicated "ground," the sink rate discrete indicated "true" for 2 seconds before it indicated and remained "not true." During the Atlanta landing, the pitch attitude was approximately 3.4 degrees when the air/ground discrete first indicated "ground" and remained "ground." The data indicated that 3.82 seconds after the air/ground discrete first indicated "ground," the nose gear squat switch indicated "ground" and remained "ground." The data indicated that 15.55 seconds before the air/ground discrete first indicated "ground," the sink rate discrete indicted "true" for 1 second before it indicated and remained "not true." During the Los Angeles landing, the pitch attitude was approximately 3.6 degrees when the air/ground discrete first indicated "ground" and remained "ground." The data indicated that 6.82 seconds after the air/ground discrete first indicated "ground," the nose gear squat switch indicated "ground" and remained "ground." The data indicated that the sink rate discrete indicted and remained "not true." The FDR ground proximity inoperative discrete, the FDR ground proximity warning discrete, and the FDR GPWS discrete for all three landings were "not true."