N1419D

HISTORY OF FLIGHT

On May 23, 2001, at 1504 central daylight time, a Fokker F28 Mk 0100 airplane, N1419D, operating as American Airlines (AA) flight 1107, was substantially damaged when the right main landing gear failed during landing (touchdown) at the Dallas-Fort Worth International Airport (DFW), Texas. The airplane was registered to and operated by American Airlines Inc., of Fort Worth, Texas. The captain, who holds an airline transport pilot certificate, the first officer, who holds an airline transport pilot certificate, two flight attendants, and 88 passengers were not injured. Visual meteorological conditions prevailed, and an instrument flight rules (IFR) flight plan was filed for the 14 Code of Federal Regulations Part 121 scheduled passenger flight. The flight originated from Charlotte, North Carolina (CLT), at 1228 and was scheduled to arrive DFW at 1507.

According to the captain and first officer, the first officer was the flying pilot for the CLT-DFW leg. The flight departed CLT, flew to DFW, and was cleared for a visual approach to runway 17C. Both flight crew members reported that the approach was flown visually, backed up with the localizer and Precision Approach Path Indicator (PAPI). They stated the approach was "stable and the touchdown was normal." The captain reported, just after initial touchdown a "loud bang" was heard, the right wing dropped, and the aircraft started to move to the right. The pilots were initially able to maintain directional control of the airplane with rudder and brake inputs; however, as speed decreased the Captain used "gentle" tiller (nose wheel steering control) inputs to assist in aligning the airplane with the runway centerline. The airplane came to a stop upright, with the right wing tip resting on the ground. The captain immediately consulted with the flight attendants and the DFW Fire Department Incident Commander, and determined that an emergency evacuation was not necessary. Subsequently, mobile stairs met the airplane and the passengers deplaned.

PERSONNEL INFORMATION

The captain holds an airline transport pilot certificate and is type rated in the F-100. At the time of the accident he had accumulated a total of 14,000 flight hours, of which 3,600 were in the F-100. He held a Federal Aviation Administration (FAA) first class medical certificate with no limitations or waivers that was issued on March 29, 2001.

The first officer holds an airline transport pilot certificate and is type rated in the F-100. At the time of the accident he had accumulated a total of 6,700 flight hours, of which 302 were in the F-100. He held an FAA second class medical certificate with no limitations or waivers that was issued on July 1, 2000.

The number one flight attendant was hired, and initially qualified in the F-100, on July 6, 2000. The number two flight attendant was hired, and initially qualified in the F-100, on May 11, 2000.

AIRCRAFT INFORMATION

The airplane was delivered new to American Airlines on June 30, 1992, and maintained in accordance with American Airlines' FAA approved airworthiness inspection program (AAIP). The airplane's maintenance records were reviewed, and there was no recent maintenance work performed that was related to the failure of the landing gear.

At the time of the accident, the airframe, to include the right main landing gear had accumulated a total of 21,589 hours (total ship time) and 15,380 cycles (total ship cycles) during its 8 years and 11 months of service.

The F28 Mk 0100 is equipped with one nose landing gear and two main landing gear; one under the inboard section of each wing. Each main landing gear was manufactured by Messier-Dowty Limited of the United Kingdom, from a forged block of grade 77-aluminum alloy (the equivalent to grade 7014-aluminum alloy in the United States). Each main landing gear is a two-wheel gear that has three support points; the forward attach, the aft attach, and the side stay strut attach. The landing gear is operated through a hydraulic system.

AERODROME INFORMATION

DFW airport is located at north 32 degrees 47.042 minutes latitude and west 097 degrees 15.205 minutes longitude, and at an elevation of 603 feet msl. The airport has two parallel runways on the west side of the airport and three parallel runways on the east of the airport, all of which are oriented north-south. The airport also has two parallel runways oriented northwest-southeast. Runway 17C is located on the east side of the airport, concrete (grooved), is equipped with a 4-light PAPI on the left side of the runway, and is 11,388 feet long and 150 feet wide.

METEOROLOGICAL INFORMATION

At 1511, the weather observation facility at DFW reported the following weather conditions: sky clear, visibility 10 miles, wind from 220 degrees at 10 knots, temperature 91 degrees Fahrenheit, dew point 54 degrees Fahrenheit, and an altimeter setting of 29.86 inches of mercury.

FLIGHT RECORDERS

The airplane was equipped with a Fairchild Model A-100A cockpit voice recorder (CVR). The CVR consisted of 34 minutes of good quality audio information on four channels, which included the accident. The CVR information confirmed that the First Officer was flying the airplane during the approach and landing. During the final approach, just prior to touchdown, the cockpit area microphone (CAM) channel captured the electronic voice announcing "50" "40" "30" "20" "10" in one second intervals. Three seconds later a bang followed by rattling sounds lasting approximately .26 seconds appeared on the CAM channel. One second later a lighter bang followed by rattling sounds lasting .34 seconds appeared on the CAM channel. Approximately 4 seconds later the FO remarked that "something [was] not right." One second later the CAM channel picked up the sounds of a "loud" bang and a rumble followed by a narrowband high pitched sound lasting approximately 36.5 seconds. Seven seconds later the Captain observed that the right main landing gear had collapsed. Fifty-six seconds after the "loud" bang, the Captain called for engine shut-down.

The airplane was equipped with an L-3 Communications Fairchild Model F-2100 digital flight data recorder (DFDR). Examination of the DFDR data confirmed that the approach was stable. The airplane initially landed with a vertical speed of less than 1 foot per second in a nose up and left wing down attitude. The airplane then became airborne a second time for a short moment and the second touchdown was in a right wing down attitude. When the air/ground switch changed from air to ground the vertical acceleration reached a maximum of 1.32 g, longitudinal acceleration reached a minimum of -0.11 g and lateral acceleration reached a maximum of 0.11 g. The longitudinal acceleration decreased to a minimum of -0.28 g and the lateral acceleration decreased to a minimum of -0.37 g.

WRECKAGE AND IMPACT INFORMATION

On scene examination of the airplane and runway revealed that the lower portion of the right main landing gear assembly separated from the airplane. A runway survey crew estimated the gear failure point to be abeam taxiway echo juliet (EJ). The first significant fractured portions of the outer case of the gear strut assembly were found on the runway at the intersection of taxiway echo kilo (EK), 776 feet from the approximate gear failure point. The right wing tip touched down 2,200 feet from the gear failure point and 65.5 feet west (right) of the runway centerline. Witness marks from the right wing tip extended from this point 2,100 feet, to the final resting position of the airplane. The inner piston of the right main landing gear, with the scissor and wheel assembly attached to it, was found 2,500 feet from the gear failure point, along the east edge of taxiway mike two (M2). The airplane came to rest 4,300 feet from the gear failure point with the nose oriented 12.5 feet to the west (right) of and parallel to the runway centerline. The right wing sustained structural damage. The forward spar of the right wing, between stations 12,375 and 13,550, was damaged.

Additionally, two runway edge lights, located on the west side of the runway, between taxiway EK and taxiway M2, were damaged.

The portion of the right main landing gear that remained attached to the airframe, and its separated portions found on/near the runway, were sent to the NTSB Materials Laboratory in Washington, D.C., for further examination.

AIRPORT EMERGENCY RESPONSE

At 1504, the DFW Fire Department was notified of the accident by air traffic control tower personnel via the emergency phone network and responded with 6 crash fire rescue (CFR) units, 2 command units, 4 police units and 4 emergency medical service (EMS) units. The first two units arrived on-scene 35 and 38 seconds after the accident occurred. All units arrived on-scene within 2 minutes of the accident. The CFR units, that were equipped with 9,000 gallons of extinguishing agent, were positioned around the airplane ready to apply agent if necessary. Contact was made between the fire department's Incident Commander and the airplane's Captain via the dedicated emergency frequency. The Incident Commander reported to the Captain that there was no fire, no fuel leak and a small amount of hydraulic fluid leaking from the right main landing gear assembly area. The Captain elected not to initiate an emergency evacuation of the airplane.

MEDICAL AND PATHOLOGICAL INFORMATION

On May 23, 2001, both pilots were tested for the presence of drugs and alcohol, and the tests were negative.

TESTS AND RESEARCH

The right main landing gear was examined at the NTSB Materials Laboratory in Washington D.C. All of the landing gear components were accounted for except for the outstop ring (part number 201072334). The steel outstop ring was later found with the use of metal detectors during the third organized search of the accident site at DFW Airport. The outstop ring was ...