SAINT LOUIS, MO, USA
N925L
Douglas DC-9-32
The captain reported that on landing, after he lowered the nosewheel and applied reverse thrust, that 'something didn't sound right. It was quieter than normal.' As the airplane slowed to taxi speed, the nose started turning right. The captain put in steering controls, but the airplane continued to turn, and began to slide. The airplane stopped near the edge of the runway, 70 degrees off runway heading. The captain then realized the engines were not operating. A witness observed the airplane being 'engulfed in a cloud of snow,' as it landed. 'It sounded like it lost intake air, then became silent.' The reported weather was a 600 foot ceiling, visibility 3/8 of a mile in snow and fog, and surface winds of 360 degrees at 16 knots gusting to 27 knots. The tower reported 1/4 inch of snow on the runway and braking action as fair to poor. A witness reported slush accumulations on the runway greater than 1/4 inch. The engine manufacturer stated the potential for engine flameout exists if 1/4 inch of slush or more is ingested when the engines are at low power, as in landing.
HISTORY OF FLIGHT On December 19, 1995, at 0911 central standard time (cst), a DC-9-32, N925L, operated as Trans World Airlines (TWA) flight 605, experienced a dual engine flameout during landing on runway 30L at Lambert International Airport, Saint Louis, Missouri. The airplane subsequently lost directional control and slid on the runway. Instrument meteorological conditions prevailed at the time of the incident. The flight was being conducted as regular scheduled domestic air carrier service under 14 CFR Part 121. An IFR flight plan was on file. There were no reported injuries to the 5 crew and 49 passengers who deplaned normally after the airplane was towed to the gate. The flight originated from Hartford, Connecticut, at 0700 eastern standard time (est). The first officer said that the first Automated Terminal Information System (ATIS) broadcast they monitored, advised the flight to expect the ILS to runway 30R. An updated broadcast reported runway 30L as the active runway, and that the runway had been plowed, sanded and deiced. The captain said that after holding for 30 minutes, they received clearance for the ILS approach to runway 30L. The first officer said that they were outside the outer marker when they configured the airplane for landing and performed the before landing check. The airplane touched down in the runway touchdown zone area. The captain lowered the nosewheel to the runway as he applied reverse thrust. The captain said that he saw the "unlock lights indicating the reversers deployed, but something didn't sound right. It was quieter than normal." The first officer said he saw the "two amber unlock lights for the thrust reversers (illuminate), but the two, blue in-reverse lights never came on." "It seemed like a long time, then multiple flags and relays came on." The captain said that he applied the brakes to slow the airplane down. As the airplane slowed to taxi speed, the nose started turning right. The captain put in steering controls, but the plane continued to turn. The first officer said that they began to slide. "The airplane stopped within half an airplane width from the edge of the runway, 70 degrees off runway heading." The captain said that he "set the brakes and then realized the engines were not operating." A mechanic at the airport, who observed the airplane land reported that when the airplane touched down, it was "engulfed in a cloud of snow. It sounded like it lost intake air, then became silent." AIRCRAFT INFORMATION Following the incident, the airplane was towed to the gate by TWA maintenance personnel. Both engines were started and run through their normal operating range. No anomalies were found with either engine during the test. The airplane underwent a post-incident maintenance inspection performed by TWA maintenance at Saint Louis, Missouri, on December 19 and 20, 1995. The number one and number two engine fuel control units were replaced. Both units were bench tested and no anomalies were found. Both engine fuel boost pumps were checked and certified for proper operation. A structural damage inspection was performed and no discrepancies were found. The airplane's left nosewheel tire was inspected by a company service engineer. He said the tire chine was in good condition and met manufacturer's specifications. The airplane's right nosewheel tire was inspected at TWA's Tire Change Station at John F. Kennedy International Airport, New York. A Quality Assurance Inspector said that the tire chine was in good condition and met manufacturer's specifications. METEROROLOGICAL INFORMATION The National Weather Service Weather Observation Facility at Lambert International Airport's 0850 est observation was a 600 foot ceiling, with visibility 3/8 of a mile in snow and fog. The temperature was 32 degrees Fahrenheit. The dew point was 31 degrees Fahrenheit. The surface winds were 360 degrees magnetic at 16 knots with gusts to 27 knots. On giving flight 605 landing clearance, the tower reported surface winds of 360 degrees at 19 knots. AIRPORT INFORMATION Prior to the incident, the Air Traffic Control Tower at Lambert International Airport broadcasted that braking action, as reported by an airport vehicle on runway inspection, was fair to poor. At approximately 0907 est, the tower broadcasted a report by another air carrier aircraft which had previously landed, that runway braking action was poor. At 0919 est, the tower broadcasted a special weather observation which included a remark of 1/4 inch of snow on the runway. The Director of Airport Field Operations for Lambert International Airport, who was directing snow removal operations when the airplane landed and observed the airplane during post- incident towing operations, described the runway's surface condition as a mix of wet snow, slush and deicing fluid. He also said that there were areas on the runway with slush accumulations greater than one-quarter inch. TESTS AND RESEARCH A representative from McDonnell Douglas, Aircraft Company, Inc., stated that the nosewheel tires chines are designed to deflect water/slush/snow away from the airplane. The specifications for tire chine design are based on data gathered during taxi tests conducted in the 1960's. A representative from Pratt and Whitney, Inc., stated that the JT-8D-9A engine is susceptible to flameout if enough water is ingested into the engine inlet. The factor the company uses for defining "enough water" is 1/4 inch of slush. The potential for engine flameout increases if the 1/4 inch of slush figure is exceeded, and if the engines are at low power, such as ground idle. The JT-8D-9A engines do not have a flight idle adjustment, therefore the engines are at ground idle when the throttles are fully retarded, as in landing. ADDITIONAL INFORMATION Parties to the investigation were the Federal Aviation Administration Flight Standards District Office, Saint Louis, Missouri, and the Air Line Pilot's Association, Bridgeton, Missouri. The airplane was released and put back into service on December 20, 1995. The flight data recorder was released and returned to TWA.
loss of induction air into the engine inlets resulting in simultaneous loss of power on both engines. Factors relating to this incident were: disconnection of the airplane's hydraulic pumps and generators, slush on the runway and the hydroplaning condition.
Source: NTSB Aviation Accident Database
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