Denver, CO, USA
N574AA
McDonnell Douglas DC-9-82
According to the flight crew, the departure, en route, and initial approach phases were reported to be without incident. During the approach, the crew selected gear down and flaps 28 [degrees] for landing and the landing weight was 127,000 pounds. The air traffic control tower reported the winds at 100 degree and 6 knots. The airplane broke out of a thin cloud layer with the base at approximately 1,000 feet above ground level. At 100 feet above the runway, the captain detected a "sinker" and then applied thrust to arrest the sink. The aircraft continued to sink in the flare and made a "very firm landing with no bounce." A review of the DFDR data revealed that a few seconds prior to touchdown, the airspeed decreased 6 knots below Vref, and the pitch attitude changed from 2.1 degrees to 5.3 degrees. A vertical acceleration of 2.032 Gs was recorded at an airspeed of 129.2 knots. Vref was calculated at 135 knots. The pilot reported applying thrust when the sink rate was detected; however, the DFDR data revealed that the engine EPR's did not increase until 7 seconds after touchdown. According to company procedures, "A stabilized approach means the airplane must be: at approach speed (VREF + additives); on the proper flight path at the proper sink rate, and at stabilized thrust. These requirements must be maintained throughout the rest of the approach for it to be considered a stabilized approach. If the stabilized approach requirements cannot be satisfied by the minimum stabilized approach heights or maintained throughout the rest of the approach, a go-around is required." The CVR recording consisted of four channels of audio information; however, none of the audio was pertinent to the incident investigation. The audio was consistent with the CVR being overwritten or recorded over by subsequent events. **This narrative was modified on May 22, 2007.**
HISTORY OF FLIGHT On March 21, 2006, at 0912 mountain standard time, a McDonnell Douglas DC-9-82, N574AA, operating as American Airlines (AA) Flight 2065, experienced a tail strike during landing at the Denver International Airport (DEN), Denver, Colorado. The airplane sustained minor damage. Visual meteorological conditions prevailed at the time of the incident. The scheduled domestic passenger flight was being conducted on an instrument flight rules flight plan under the provisions of Title 14 Code of Federal Regulations Part 121. The captain, first officer, 3 flight attendants, and 133 passengers on board were not injured. The flight originated at the Dallas-Fort Worth International Airport, Fort Worth, Texas, at 0815 central standard time, and was en route to DEN. The departure, en route, and initial approach phases were reported to be without incident. According to the captain's statement: "On vectored approach to Denver [Instrument Landing System] 35L, we intercepted the localizer outside of CRUUP (19.8 [Distance Measuring Equipment, DME]) at 10,000 feet assigned. Approach Control told us to maintain 10,000 feet until CRUUP. Between CRUUP and CHOLA (16.6 DME), we experience some wake turbulence and asked approach what type of aircraft we were following. Approach told us it was an Airbus 320 and then asked us to slow to 160 [knots] and then 150 knots shortly thereafter. We noticed that the Airbus was about 4.5 miles ahead of us according to [Traffic Collision Avoidance System]. We then asked the Controller what speed the Airbus was doing. The controller responded, 'You're speed is good!!' We then intercepted the glidepath and continued the approach. We selected gear down and flaps 28 [degrees] for landing and our landing weight was 127,000 pounds. Tower reported winds at 100 degree and 6 knots. We broke out of a thin cloud layer with the base at approximately 1,000 feet above ground level. At 100 feet above the runway, I detected a sinker and then applied thrust to arrest the sink. Aircraft continued to sink in the flare and we made a very firm landing with no bounce. We then taxied normally to the gate and prior to gate arrival, the first officer contacted [company operations] to ask maintenance to come check aircraft for a hard landing. During post flight walk around, first officer and maintenance noticed damage to tail skid plate and scraped drain tubes." According to the first officer's statement: "...At about 100 feet above the runway, the captain and I detected a sink rate and the captain applied thrust to arrest the sink. The aircraft continued to sink in the flare and made a very firm touchdown with no bounce..." PERSONNEL INFORMATION Captain The captain held an airline transport pilot certificate with a multi-engine land airplane rating, type ratings for Boeing 757, 767, and McDonnell Douglas DC-9 airplanes, and a flight engineer certificate for turbo-jet powered airplanes. According to company records, at the time of the incident, he had 20,035 hours total time; with 10,100 hours in the DC-9-82. The captain was issued a first-class medical certificate on November 28, 2005, with no restrictions or limitations. The captain had no history of incidents, accidents or Federal Aviation Administration (FAA) enforcement actions for his pilot and flight engineer certificates and ratings. First Officer The first officer held an airline transport pilot certificate with a multi-engine land airplane rating, a type rating for McDonnell Douglas DC-9 airplanes, and a flight engineer certificate for turbo-jet powered airplanes. According to company records, at the time of the incident, he had 9,700 hours total time; with 3,400 hours in the DC-9-82. The first officer was issued a second-class medical certificate on February 23, 2006, with a restriction for corrective lenses. The first officer had no history of incidents, accidents or FAA enforcement actions for his pilot and flight engineer certificates and ratings. AIRCRAFT INFORMATION N574AA, a McDonnell Douglas DC-9-82, serial number 53151, was issued a standard airworthiness certificate in 1991. The airplane was registered to the owner on July 2, 1991. The airplane was equipped with two Pratt and Whitney JT8D-200 series turbofan engines. At the time of the incident, the airframe had accumulated 43,793 total hours, the number one engine 4,527 hours since major overhaul and the number two engine 15,780 hours since major overhaul. According to AA, at the time of the incident, the following aircraft configurations were reported: Weight - 127,000 pounds, Flap Setting - 28 degrees, and Center of Gravity - 13.7 percent. According to the aircraft maintenance logbook, after the incident, the captain entered the following discrepancy: "Check a/c for very firm landing @ DEN following A320 on ILS [with] tailwind @ 127,000#." METEOROLOGICAL INFORMATION At 0853, the DEN automated surface observing system (ASOS) reported the wind from 110 degrees at 4 knots, 6 statute miles visibility, mist, few clouds at 300 feet, scattered clouds at 800 feet, ceiling broken at 20,000 feet, temperature minus 9 degrees Celsius, dew point minus 12 degrees Celsius, and an altimeter setting of 30.05 inches of Mercury. AERODROME INFORMATION The Denver International Airport, DEN, is a public, controlled airport located 16 miles northeast of Denver, Colorado, at 39 degrees, 51.699 minutes north latitude, and 104 degrees, 40.390 minutes west longitude, at a surveyed elevation of 5,431 feet. Runway 35L is constructed of grooved concrete and is 12,000 feet long and 150 feet wide. The runway is equipped with a 4-light precision approach path indicator (PAPI) on the right side, and the glide slope was set to 3.00 degrees. FLIGHT RECORDERS A copy of the flight data recorder (FDR) data from flight 2065 was forwarded by American Airlines to the NTSB's Vehicle Recorder laboratory. A FDR group for this incident was not formed. The data was transcribed using laboratory software and converted into engineering units using FDR documentation specific to the recording configuration for an American Airlines MD-82 aircraft. The FDR data contained the entire flight during which the incident occurred. The duration of the flight from takeoff to touchdown was approximately 1 hour and 40 minutes. Timing of the FDR data, as transcribed from the recorder, was to the nearest second. The airplane was equipped with a L-3 Communications FA2100-1020 cockpit voice recorder (CVR). This model CVR was a solid-state CVR that recorded 2 hours of digital cockpit audio. The CVR was sent to the NTSB's Vehicle Recorder laboratory for readout. A CVR group for this incident was not formed. Examination of the CVR revealed that the unit had not sustained any heat or structural damage and the audio information was extracted from the recorder normally, without difficulty. The CVR recording consisted of four channels of audio information; however, none of the audio was pertinent to the incident investigation. The audio was consistent with the CVR being overwritten or recorded over by subsequent events. WRECKAGE AND IMPACT INFORMATION Examination of runway 35L by DEN airport operations revealed the tail strike occurred approximately 575 feet from the runway threshold, and the strike mark was approximately 30 feet in length. Examination of the airplane by the NTSB investigator-in-charge and a NTSB structures engineer revealed minor damage to the tail skid and several vent tubes. PATHOLOGICAL INFORMATION Flight crew toxicological testing was not accomplished. TESTS AND RESEARCH A review of the FDR data revealed the autopilot was disconnected at 0906:38 and then reengaged at 0907:56, at a radio altitude of 4,489 feet. The landing gear was down and locked at 0910:40, at a radio altitude of 1,434 feet. At 0910:48, the flaps were extended to 28 degrees. The autopilot was disconnected at 0911:53. Following the autopilot disconnect, the control column moved aft from 9 degrees to 25 degrees. Between 0911:55 and 0911:57, the pitch attitude changed from 2.1 degrees to 5.3 degrees, respectively. At 0911:58, a vertical acceleration of 2.032 Gs was recorded at an airspeed of 129.2 knots. Vref was calculated at 135 knots. From 0911:00 to 0912:04, the left and right engine pressure ratios (EPR) remained at 1.1. At 0912:05, the left and right EPRs increased to 1.2. Thrust lever positions were not recorded. See Flight Data Recorder report for additional information. ADDITIONAL INFORMATION Stabilized Approach Criteria American Airlines DC-9 Operating Manual indicated the following stabilized approach criteria: "1.3 Stabilized Approach Requirements (FAA Order 8400.10) A. Significant speed and configuration changes during an approach can complicate aircraft control, increase the difficulty of evaluating an approach as it progresses, and complicate the decision at the decision point; i.e., DA, DH, MDA. A pilot must assess the probable success of an approach before reaching the decision point. This requires the pilot to determine that requirements for a stabilized approach have been met and maintained. To limit configuration changes at low altitude, the aircraft must be in landing configuration by 1000 feet [above field level] (gear down and landing flaps). A stabilized approach must be established before descending below the following minimum stabilized approach heights: * IMC - 1000 feet AFL * VMC - 500 feet AFL A stabilized approach means the airplane must be: * At Approach Speed (VREF + additives) * On the proper flight path at the proper sink rate * At stabilized thrust These requirements must be maintained throughout the rest of the approach for it to be considered a stabilized approach. If the stabilized approach requirements cannot be satisfied by the minimum stabilized approach heights or maintained throughout the rest of the approach, a go-around is required." FAA Order 8400.10 Chapter 2, Section 3, Part 511. Stabilized Approach Concept, defines a stabilized approach as the following: "...A stabilized approach for turbojet aircraft means that the aircraft must be in an approved landing configuration (including a circling configuration, if appropriate), must maintain the proper approach speed with the engines spooled-up, and must be established on the proper flightpath before descending below the minimum 'stabilized approach height' specified for the operation being conducted. These conditions must be maintained throughout the rest of the approach for it to be considered a stabilized approach. Operators of turbojet aircraft must establish and use procedures that result in stabilized approaches..." Cockpit Voice Recorder The NTSB investigator-in-charge (IIC) was notified of the incident via telephone by the DEN control tower as the airplane was taxiing to the gate. DEN tower personnel were in contact with American Airlines operations personnel at the time of the telephone call. During the telephone call, the NTSB IIC requested to the DEN tower controllers that American Airlines operations personnel inform the flight crew that the CVR and FDR were to be secured. When the NTSB IIC arrived on-scene, AA maintenance personnel were on-board the airplane performing the required maintenance actions for replacement of the FDR. The NTSB IIC requested the CVR be removed, at which point, the AA maintenance personnel replied, "Why, it's already been recorded over." The NTSB IIC requested AA maintenance personnel remove CVR, and the NTSB IIC sent the unit to the NTSB Vehicle Recorder's laboratory for examination and readout. According to American Airlines Flight Manual Part 1, Chapter 5, Voice Recorder, section 5.3, NTSB Investigation, subsection A, "In the event of an accident or occurrence requiring immediate notification to the National Transportation Safety Board and which results in the termination of flight, the NTSB may request AA retain the recorded information. Information obtained from the voice recorder may be used to assist in the determination of the cause of the accident or occurrence. To accomplish this, it is necessary for the Captain to pull the voice recorder circuit breaker prior to leaving the aircraft. The tape cannot be used in any civil penalty or certificate action." **This narrative was modified on May 22, 2007.**
the captain's failure to follow existing company procedures for stabilized approach. **This report was modified on May 23, 2007.**
Source: NTSB Aviation Accident Database
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