Aviation Accident Summaries

Aviation Accident Summary FTW94IA046

DFW AIRPORT, TX, USA

Aircraft #1

N166AW

BOEING 737-33A

Analysis

WHILE CONDUCTING AN ILS APPROACH IN GROUND FOG AND BRIGHT NIGHT CONDITIONS, THE PILOT-IN-COMMAND FAILED TO ATTAIN THE GLIDE SLOPE AND THE COPILOT FAILED TO ADVISE HIM OF THIS. GLIDESLOPE RATE OF DESCENT AT APPROACH GROUND SPEED SHOULD HAVE BEEN APPROXIMATELY 360 FEET PER MINUTE. THE PILOT DESCENDED THE AIRCRAFT THROUGH THE GLIDE SLOPE AT A RATE OF DESCENT OF 1,215 FEET PER MINUTE WHEN 300 FEET OFF THE GROUND. THE RATE OF DESCENT AT TOUCHDOWN WAS APPROXIMAELY 600 FEET PER MINUTE AND TOUCHDOWN OCCURRED 1,095 FEET SHORT OF THE RUNWAY THRESHOLD. FOLLOWING INITIAL TOUCHDOWN, THE AIRCRAFT BECAME AIRBORNE FOLLOWED BY A SECOND TOUCHDOWN. DURING THE GROUND ROLL THE AIRCRAFT IMPACTED 5 SETS OF APPROACH LIGHTS OFF THE END OF THE RUNWAY. AS THE AIRCRAFT ROLLED ONTO THE RUNWAY THRESHOLD IT AGAIN BECAME AIRBORNE WHEREUPON THE CREW ABANDONED THE APPROACH AND PROCEEDED TO AN ALTERNATE DESTINATION. UPON ARRIVAL AT THE ALTERNATE A FLY-BY WAS PERFORMED SO THE TOWER COULD ASSESS POSSIBLE LANDING GEAR DAMAGE. THIS WAS FOLLOWED BY A NORMAL LANDING.

Factual Information

On December 8, 1993, at 0532 central standard time, a Boeing 737- 33A, N166AW, operating as America West flight 754, touched down approximately 1,095 feet short of runway 18L at Dallas/Fort Worth International Airport (DFW). The 64 passengers and 5 crew members were not injured, and the aircraft sustained minor damage. The flight was operating under 14 CFR Part 121 and an IFR flight plan was filed. The flight originated in Las Vegas, Nevada. Instrument meteorological conditions prevailed. Witness marks off the approach end of runway 18L consisted of a ground scar which extended for 117 feet. This was followed by a lack of marks for 157 feet and then a ground scar of 560 feet which ended on the runway threshold. In the area where the ground scar was located, five sets of approach lights were destroyed. According to witness information, and information gained through the crew statements, after becoming airborne the second time, the aircraft proceeded to Houston Intercontinental Airport (IAH), Houston, Texas, and an emergency was declared en route. A fly-by was performed prior to landing at Houston for the purpose of assessing possible landing gear damage. This was followed by a normal landing. (See attached photographs.) According to the captain's written statement "We were VMC and saw runway lights below a thin undercast layer. I descended and waited for the auto pilot to intercept the glide slope. Just as we broke into the clear, the GPWS went off. I responded to the GPWS per company procedure." The co-pilot's report was similar to the captain's. He reported that "We touched the ground briefly and then the aircraft became airborne again. I reported missed approach and cleaned up the aircraft on schedule." Weather at DFW at the time of the occurrence was reduced visibility with an RVR of 6,000+ feet and fog. The cockpit voice recorder and flight data recorder were removed from the aircraft after the flight arrived in Houston and sent to the Board Research and Engineering Laboratory for analysis. The cockpit voice recorder contained no information pertinent to the incident. Elapsed time with the recorder operating resulted in the incident time span being recorded over due to built in design parameters of the recorder. The flight data recorder technical report is attached. The recorded data provided information concerning the approach, initial touchdown, secondary touchdown, and subsequent lift off and climb. The data provided the following information: Main gear touchdown occurred at a nose attitude of plus 10 degrees and 3 degrees left wing down on a heading of 171 degrees. Altitude at touchdown was 617 feet above mean sea level, and the indicated airspeed was 118 knots. The data also indicated a peak vertical acceleration of 3.18 positive "g". A copy of the technical report is attached. A voice recording of conversation between the crew and the dispatcher was obtained from the operator. A transcript of that recording is attached. Also attached are crew statements. The flight was on an ILS approach with clearance for the approach given at a distance from the final approach fix which allowed for full configuration prior to the fix. Calculation provided information that the aircraft passed through the glideslope 300 feet above ground level at a rate of descent of 1,215 feet per minute and that touchdown occurred at a rate of descent of approximately 600 feet per minute. The rate of descent for the aircraft to remain on the glideslope at a calculated ground speed of 120 knots should have been approximately 360 feet per minute. (See attached diagram.) Following the incident, a flight check of the facility was performed. The ILS system for runway 18L met specifications. A report of the flight check is attached.

Probable Cause and Findings

A FAILURE BY THE PILOT-IN-COMMAND TO ATTAIN A STABILZED APPROACH. FACTORS WERE THE FOG AND FAILURE OF THE COPILOT TO MONITOR THE APPROACH.

 

Source: NTSB Aviation Accident Database

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