Douglas DC-6B accident at Los Angeles, California, 17 Dec 1963 (N93131)

Accident narrative

Western Air Lines Flight 221, a Douglas DC-6B (N93131), struck runway 25L with its Nos. 1 and 2 propellers while executing a go-around in fog at Los Angeles International Airport on December 17, 1963, at 2341 P.s.t. The aircraft climbed out on three engines and diverted to Burbank, California, where it landed safely. There were no injuries to any of the 46 occupants.

**The flight**

Flight 221 was a regularly scheduled passenger flight nonstop from San Francisco to Los Angeles. The crew consisted of the captain, first officer, second officer, two stewardesses, and a company check pilot. The captain had 15,200 flight hours, including 5,000 in the DC-6B. Because this was his first trip as pilot-in-command since June 1960, the check pilot was assigned to requalify him for the route.

Prior to the flight's initial departure from Los Angeles earlier that evening, a company dispatcher advised the captain to expect fog with low visibility upon his return, despite U.S. Weather Bureau forecasts calling for clear skies. By the time the flight departed San Francisco, the Los Angeles forecast had been amended to predict ground fog and partial obscurations.

**The approach and go-around**

Approaching the Los Angeles terminal area, the flight received weather updates reporting partial obscuration, half-mile visibility, and ground fog. The 2300 observation included a Runway Visual Range (RVR) for runway 25L of more than 6,000 feet. The flight was cleared for an Instrument Landing System (ILS) approach and received Precision Approach Radar (PAR) advisories. PAR noted minor deviations left of course, which the crew corrected.

The captain stated that between the outer and middle markers, visual contact was made with the approach and runway lights. He reported seeing at least half a mile of visibility and called for full flaps and landing lights. The crew described a normal flare and touchdown, which they estimated occurred 1,000 feet down the runway. The aircraft was configured with the landing gear down, flaps fully extended to 50 degrees, and all propellers set at 2300 r.p.m.

Immediately after landing, the aircraft entered a dense fog condition that reduced visibility to zero. The captain initiated a go-around, calling for full power and flaps to 20 degrees. He stated he rotated the airplane at the V2 speed of 100 knots. The first officer placed the master propeller control forward and moved the flap selector to 20 degrees. The second officer monitored the engine instruments, noting they were producing go-around power.

Shortly after becoming airborne, the check pilot warned the captain, "you are sinking, pull up." The captain heard a noise and felt the aircraft brush something, but maintained his attitude and speed until the airplane began to climb. At an altitude of approximately 500 feet, the captain called for the landing gear to be raised.

During the climbout, the check pilot observed the No. 2 engine oil pressure warning light illuminate and the tachometer drop below 1,000 r.p.m. He commanded the propeller feathered. The second officer engaged the switch, but unknown damage prevented the feathering action. A visual inspection from the cabin revealed the No. 2 propeller was missing and the engine nacelle was drooped. The flight diverted to Burbank and landed without further incident.

**What the investigation found**

The No. 2 engine nose case and propeller assembly had separated from the aircraft and were found on runway 25L, approximately 6,400 feet beyond the displaced threshold. The No. 1 propeller blades were bent forward with their tips ground off. The left main landing gear doors were abraded, and an inboard brake line was separated. The nose gear and right main gear were undamaged.

Tire marks from the main landing gear and propeller slash marks from the Nos. 1 and 2 engines were found on the runway. The initial tire mark from the left main gear began 5,430 feet beyond the displaced threshold, followed 59 feet later by slash marks from the No. 2 propeller. Based on the distance between the propeller slash marks, the Board computed a ground speed at impact of approximately 126 to 127 knots. Using this speed and performance acceleration data, the Board calculated that the actual lift-off point was about 3,250 feet beyond the threshold. This indicated that the initial touchdown occurred between 2,000 and 2,400 feet down the runway, rather than the 1,000 feet estimated by the crew.

The Board noted that the reported RVR of 5,000 feet and the tower visibility of half a mile were not representative of the patchy, dense fog that existed beyond the approach end of the runway.

Performance data showed the DC-6B could climb at 725 feet per minute in the go-around configuration. Establishing this climb required an initial five-degree nose-up rotation, increasing to an eight-degree angle of attack as the flaps retracted to 20 degrees. Because the tail skid did not strike the runway, the Board determined the aircraft's longitudinal attitude at impact was less than five degrees nose-up. The Board concluded the aircraft was not rotated sufficiently to maintain a positive rate of climb.

Furthermore, the Board concluded the landing gear was in the process of retracting when the aircraft settled onto the runway. The aircraft's dimensions meant that propeller contact could not occur with the main landing gear fully extended and locked without prior structural damage to the gear. Although the crew stated the gear handle was not moved until after the impact, the Board concluded it was placed in the retract position shortly after initial lift-off.

The investigation identified conflicting company procedures regarding the sequence of gear and flap retraction during a go-around. A memorandum issued a month prior to the accident had shifted gear retraction duties to the first officer and power setting duties to the second officer. The captain had not briefed the crew on these changes. The Board noted that the first officer assumed the second officer's duties by advancing the propeller control, and believed a lack of crew coordination and understanding existed.

**Probable cause**

The Board determines the probable cause of this accident was "the failure of the pilot to maintain a positive rate of climb and the premature retraction of the landing gear during a go-around in fog conditions."