Accident at Las Vegas, Nevada, 25 Sept 1963 (N-67935)

Accident narrative

On September 25, 1963, at 2103 Pacific daylight saving time, an AAXICO Airlines C-46-F, registration N 67935, crashed at McCarran Field in Las Vegas, Nevada. Following a fire warning in the left engine, the crew attempted an emergency single-engine landing on runway 1. During the rollout, the landing gear collapsed, and the aircraft slid to a stop 180 feet beyond the end of the runway. The pilot and first officer were uninjured, but the aircraft received substantial structural damage.

**The flight**

AAXICO LOGAIR Flight 14/25 was a cargo flight operated under contract for the United States Air Force. The flight originated at Hill Air Force Base in Ogden, Utah, and was scheduled to return there after en route stops at Nellis Air Force Base, Nevada, and Norton Air Force Base, California.

The crew consisted of Captain William P. Beavers, who had 5,276 total flight hours including 1,668 in C-46 aircraft, and First Officer Kalman E. Saufnauer, who had 1,251 total hours with 246 in the C-46.

The flight departed Nellis at 2049. The aircraft’s takeoff weight was 42,616 pounds, well below the maximum allowable 48,000 pounds, and the center of gravity was within limits. Prior to departure, the fire-detector system was tested and found to be functioning properly.

**The emergency and approach**

Approximately ten minutes after takeoff, while the aircraft was climbing between 6,500 and 7,000 feet about ten nautical miles south of McCarran Airport, a steady fire-warning light illuminated for the left engine. The crew immediately shut down the engine, feathered the propeller, pulled the fire-wall shutoff handle, discharged the CO2 bottles, and reversed course. The first officer visually inspected the engine but saw no indication of fire. However, the fire-warning light and bell continued to operate.

The crew declared an emergency and established radio contact with McCarran Tower, which advised that the wind was from 270 degrees at 10 knots and that any runway was available.

The captain stated that after turning back, he found the aircraft lined up with runway 1. Apprehensive of a wheel-well fire, he made a rapid straight-in descent at 155 knots. One mile from the runway end and 500 feet above the ground, the captain retarded the right engine throttle and pitched the nose up to reduce airspeed to 130 knots. He lowered the flaps to the full down position and instructed the first officer to extend the landing gear.

During the approach, the fire-warning bell rang continuously, which prevented verbal instructions between the pilots and could have made the gear warning horn inaudible. The captain stated that as the aircraft passed over the runway threshold at approximately 100 feet and 105 knots, he had difficulty observing the gear-down indicator light due to the glare from the illuminated fire-warning, fuel pressure, and oil pressure lights. He stated he was unaware that a cut-off switch for the fire-warning bell was located on the instrument panel. Neither pilot checked the hydraulic pressure following the gear extension or during the approach.

About one-third of the way down the runway, the captain was uncertain if the landing gear was down and locked. He momentarily applied full power to the right engine to ensure adequate hydraulic pressure, then fully retarded the power. Touchdown occurred approximately halfway down the runway. The flaps were immediately retracted, and brakes were applied after rolling about 500 feet. During heavy braking, the landing gear retracted, and the aircraft slid on its belly.

**What the investigation found**

Heavy tire skid marks began 4,775 feet down the lighted 5,878-foot runway. The aircraft was found with the main landing gears retracted on their up latches, and the landing gear actuation lever in the "DOWN" position.

Examination of the left engine revealed a cracked exhaust adapter and oil leakage from the rocker-box covers. The Board noted that a small flash fire or excessive heat from the exhaust leakage likely activated the fire detector. The Board believed a short circuit, caused by normal engine vibration grounding the system to the airframe, allowed the warning light and bell to remain on after the engine was shut down.

Flight tests in another C-46 demonstrated that the hydraulic pump of a single engine operating at idle provides sufficient pressure to extend or retract the landing gear and flaps. The Board concluded the captain's momentary addition of power during the approach was unnecessary, as it could not increase hydraulic pump output.

The captain stated he had no intention of making a missed approach. The first officer stated that when power was added, he thought a missed approach was being executed, but realized it was not when the power was immediately retarded. The first officer stated he was concerned they might roll into the over-run, was getting ready for it, and had his hand on the gear actuation lever. When asked if he could have moved the lever to the "UP" position, he replied, "I don't think so. I'd say no," and stated he did not recall attempting to raise it.

The Board believed that the landing gear was down and locked when the aircraft passed the threshold, but that the first officer actuated the gear lever to the "UP" position in anticipation of a missed approach. Because the weight of the airplane was off the gear, it began to retract. When the power was retarded and the first officer realized a go-around was not contemplated, he repositioned the lever to the "DOWN" position. However, placing the lever down was ineffective because there was insufficient time (13 seconds required) for the gear to fully extend and lock before touchdown.

The gear subsequently collapsed under the weight of the aircraft as the landing roll speed diminished. The Board noted that touching down 4,775 feet down the runway left only 1,100 feet remaining, making it obvious that the pilot could not have stopped his aircraft on the runway.

**Probable cause**

The Board determines the probable cause of this accident was "the improperly executed approach and landing procedures during an emergency single-engine operation resulting in an overshoot."