American Airlines Flight 157

From Wikipedia, the free encyclopedia

**American Airlines Flight 157**
Summary
Date	November 29, 1949
Type	Pilot error
Site	Dallas Love Field, Dallas, Texas
Fatalities	28
Injuries	16
Aircraft
Aircraft type	Douglas DC-6
Operator	American Airlines
Tail number	N90728
Passengers	41
Crew	5
Survivors	18

American Airlines Flight 157, a Douglas DC-6, was flying on November 29, 1949 from New York City bound for Mexico City with 46 passengers and crew. After one engine failed in mid-flight, a series of critical mistakes by the flight crew caused the pilot to lose control of the plane during the final approach to a routine stopover at Love Field in Dallas, Texas. The airliner slid off the runway and struck a parked airplane, a hangar, and a flight school before crashing into a business across from the airport. 26 passengers and two flight attendants died. The pilot, co-pilot, flight engineer, and 15 others survived.

1 Flight history
2 Crash
3 Aftermath
4 Investigation
5 See also
6 References
7 External links

[edit] Flight history

The American Airlines DC-6, carrying a registration number of N90728 and the title "Flagship of South Carolina", had taken off from LaGuardia Airport in New York City bound for Mexico City with intermediate stopovers at Washington National Airport and Dallas Love Field.^[1] After the stop in Washington D.C., the flight was carrying 41 passengers and 5 crew members: Captain Laurens "Tommy" Claude, First Officer Robert Lewis, Flight Engineer William S. Forbes, and flight attendants Josephine Cadena and Margaret Van Bibber.^[2]

The flight was uneventful until the No. 1 engine, the outboard engine on the left wing, began backfiring and running roughly as the airplane neared Nashville, Tennessee. After reducing power and attempting corrective measures, the flight crew shut down the engine and feathered the propeller near Altheimer, Arkansas.^[3] Engine failures were considered fairly routine events on piston-engined airliners in the 1940s, so the crew elected to continue the flight to Dallas, and Captain Claude announced to the passengers that they would switch to another airplane upon arrival.^[4]

[edit] Crash

At 5:25 AM, as they approached Dallas airspace, the crew of Flight 157 alerted air traffic control that they were flying on three engines. The flight was given permission to enter the traffic pattern at Love Field at 5:36 AM. Weather in Dallas was clear, with visibility of 1.5 miles (2.4 km), and no other air traffic was reported in the area. Captain Claude ordered the crew to lower the flaps and landing gear. At 5:45 AM, the pilot made a right-hand turn to land on Runway 36, but the airplane came out of the turn slightly to the left of the runway. An "S"-turn was initiated to align the DC-6 with the runway centerline.^[1]^[5]

The plane suddenly shook and its airspeed dropped precipitously. The left wing dropped sharply and the plane began to turn to the left. Flight Engineer Forbes noted that the fuel flow meter was not indicating any flow to the No. 4 engine. Captain Claude quickly applied full throttle and ordered Forbes to apply the booster pump, which increases the fuel flow to the engines in emergencies.^[6] The captain applied full right aileron in an attempt to raise the dropping left wing, and ordered First Officer Lewis to raise the flaps and landing gear, intending to circle the airport and attempt another landing (known as a go-around). Lewis raised the landing gear but failed to raise the flaps, stating later that he “was afraid” to raise them due to the airplane’s low airspeed and its close proximity to the ground, fearing that the airplane would immediately stall if he complied with Claude's order.^[6] Lewis then noticed that the No. 4 engine’s fuel pressure was zero and its RPM was dropping, and he feathered the prop, hoping that the resulting reduction in drag would help the airplane climb.^[6] However, with the flaps down and only two of the four engines providing thrust, it was impossible for the ill-fated DC-6 to accelerate to a speed that would allow it to remain airborne. The craft was now headed on a path crossing Runway 36 approximately 40 degrees to the left and was still rapidly losing altitude. Lewis reportedly exclaimed “she’s a goner” as the captain raised the airplane's nose in a futile attempt to climb. Instead of climbing, the crippled airliner stalled, slamming into the runway tail-first.^[1]^[3]

The airplane careened off the left side of the runway, bouncing into the air as it struck a parked airplane (identified in newspaper reports only as an "an old Army Air Force trainer") and set it ablaze.^[5] The airliner's left wing cut through the wall of a hangar, causing the roof to partially collapse, and then exploded into flames as its right wing tore through the Dallas Aviation School. The craft then struck the ground, broke into several pieces, and turned sideways as it slid across Love Field Drive, finally coming to rest after plowing into a building owned by the American Magnaflux Corporation.^[5]^[2]^[1]

[edit] Aftermath

The 15 surviving passengers escaped in the initial seconds after the crash, scrambling through a gaping hole in the forward fuselage and through the emergency exit doors over the wings.^[4]^[7] The cockpit section of the aircraft had separated from the fuselage, helping the flight crew to escape the fire. Most survivors escaped with only minor injuries. Albert LeLaurier, a 22-month-old child, survived after being pulled out from under one of the airliner’s seats by his parents.^[8]

Only one passenger would die of his injuries after managing to escape from the burning aircraft.^[2] The remaining 25 passengers and two flight attendants were trapped in the wreck as the flames quickly grew too intense to allow any rescue attempts. Firefighters fought the massive blaze for at least 30 minutes before the wreckage could be approached, by which time many of the victims were charred beyond recognition.^[2]^[5] The Dallas Aviation School and American Magnaflux buildings were almost completely destroyed and the hangar was extensively damaged. The parked airplane that was struck by the DC-6 burned so extensively that little remained of it afterwards.^[5]

The dead included Lt. Col. A.F.S. Fane, a British King's Messenger on an official mission to Mexico and Guatemala, and José de la Mora, a prominent Mexican banker. Several other Mexican nationals died, including other members of the de la Mora family.^[2]^[5]

[edit] Investigation

The Civil Aeronautics Board (CAB) held a hearing in Dallas in December 1949 to investigate the causes of the accident. During the hearings, it was revealed that neither Claude nor Forbes knew at the time of the crash that Lewis had feathered the No. 4 propeller- in fact, Claude did not realize it until hearing Lewis’ statement being read to the CAB.^[6]

After investigating the remains of the aircraft, conducting flight tests to replicate the accident scenario, and completing the hearing, the CAB concluded in August 1950 that the probable cause of the accident was "the faulty execution of an engine-out approach."^[1] There were a series of significant mishaps by the crew that contributed to the final outcome:

The captain failed to align the aircraft with the runway centerline after the final turn.
After realizing the misalignment, the captain attempted to correct it with a risky "S"-turn at very low altitude. There is little room for error if a problem arises during this maneuver because the climb performance of an airplane decreases with increasing angle of bank. Modern airline procedures generally ban low-altitude "S"-turns for this reason.
The captain initiated the “S”-turn with the flaps down, further increasing the risk.
The crew made no attempt to balance the airplane’s fuel load after the No. 1 engine failed. The DC-6 is equipped with four main fuel tanks that serve individual engines, although a network of valves allow fuel to be transferred from one engine’s tank to the others in emergencies. The crew failed to comply with the recommended procedure to transfer fuel from a tank serving a failed engine into the other engines’ tanks to balance the weight of the fuel load on each side of the plane. Flight 157 had flown for almost three hours with the No. 1 engine out, and consequently, the CAB concluded that the No. 1 main fuel tank was holding about 1,400 lbs (635 kg) more gasoline than the other three main tanks when the plane arrived at Love Field. The investigators concluded that the added weight at the outboard end of the left wing had been one of the main causes of the wing’s sharp drop when the “S”-turn was initiated.^[9]
The captain applied excessive rudder during the “S”-turn, causing the airplane to fly slightly sideways in relation to the intended flight path, known in aviation terminology as a skid. This maneuver would have caused the plane’s airspeed to drop, and according to the CAB findings, it also caused the fuel in the No. 4 main tank to slosh away from the tank’s fuel outlet, lowering the No. 4 engine’s fuel pressure and causing the engine to surge.^[9] The CAB report noted that the fuel level might not have been so low as to slosh away from the outlet had the crew transferred some fuel from the No. 1 main tank into the No. 4 main tank.
The captain’s application of full throttle to both right-hand engines caused to airplane to turn further to the left due to the relative lack of thrust from the single functioning left-hand engine. This exacerbated his loss of directional control.
The first officer disobeyed the captain’s order to raise the wing flaps^[6], hindering the plane's ability to climb and the captain’s ability to anticipate the plane’s responses to control inputs (an airplane typically responds differently depending on the position of the flaps).
The first officer misinterpreted the No. 4 engine’s fuel pressure drop as a sign of incipient engine failure. He feathered the prop of an engine that the CAB would later conclude was probably fully functional at the time. Ironically, the CAB partially exonerated Lewis for this act- they concluded that the craft was so close to the ground at that point that his mistake probably had little bearing on the final outcome of the crash.^[9]
The first officer failed to notify the other two crew members that he had failed to raise the flaps or that he had feathered the No. 4 prop.
Excessive elevator input by the captain caused the aircraft to stall.

The accident probably would have been avoided had the crew held the plane straight and level, raised the flaps, climbed to a safe altitude, circled the airport, and attempted another landing. The CAB concluded that there were no factors present that would compel the crew to land immediately despite the sloppy approach (such as rapidly deteriorating weather or a shortage of fuel).

The crash of Flight 157 was the deadliest air disaster in Texas history at the time. As of December 2006, it remains the worst air tragedy to take place at Dallas Love Field.

American Airlines has used the Flight 157 designation after the disaster. The number was recently used for a flight from Los Angeles International Airport to Kahului Airport that was discontinued on January 3, 2007.

[edit] See also

[edit] References

^ ^a ^b ^c ^d ^e Aviation Safety Network. Accident description. Retrieved on December 23, 2006.
^ ^a ^b ^c ^d ^e Staff writers. "Worst Plane Crash In Texas History Takes Lives of 28", The Dallas Morning News, 1949-11-30.
^ ^a ^b Staff writers. "Two Engines Failed, Crash Pilot Reveals", The Dallas Times Herald, 1949-11-29, pp. 1,6.
^ ^a ^b Sommers, Ruth. "Airliner 'Trembled' Seconds Before Crash", The Dallas Times Herald, 1949-11-29, p. 10.
^ ^a ^b ^c ^d ^e ^f Staff writers. "28 Die in Dallas Crash", The Dallas Times Herald, 1949-11-29, pp. 1,11.
^ ^a ^b ^c ^d ^e Page, Clint. "Death Ship’s Copilot Halted Second Motor", The Dallas Morning News, 1949-12-14.
^ Staff writers. "Calm Man Gives View Of Escape", The Dallas Times Herald, 1949-11-29, p. 10.
^ Murphy, Charles & Bradford, Ben. "Trip Nearing End, Then Came Crash", The Dallas Morning News, 1949-11-30.
^ ^a ^b ^c Hornaday, Walter. "CAB Gives Findings on DC-6 Crash", The Dallas Morning News, 1950-08-31.