12 March 1969

 

Lockheed AH-56A Cheyenne (Lockheed Martin)

12 March 1969: At 11:56 a.m., a prototype Lockheed AH-56 Cheyenne compound helicopter, serial number 66-8828 (manufacturer’s serial number 1003), was destroyed during a test flight off the coast of Southern California. The test pilot, David A. Beil, was killed.

The Los Angeles Times reported:

Pilot Killed in Crash of Experimental Helicopter

CARPINTERIA — An experimental helicopter under test for the Army caught fire, exploded and crashed in the sea half a mile off the community of Santa Claus, two miles north of here, Wednesday.

The pilot, identified as David Beil, 32, of Thousand Oaks by a spokesman for Lockheed-California Co., which was testing the aircraft, was killed.

Lockheed-California described the helicopter as an AH-56A Cheyenne, a rotary-winged craft with a short fixed wing and two rotors.

It was a two-place ship but only the pilot was aboard as it flew along the coast, simulating low-level military attack, with a chase plane close behind.

Witnesses on the beach said the aircraft suddenly began to trail a plume of smoke and that flames appeared. They heard an explosion, and one of them, Jack Hamm, said:

“The tail rotor separated and fell, and the whole aircraft was falling apart, I saw no survivors.”

The fuselage apparently sank, but searchers recovered some wreckage and portions of a body. Part of a helmet stenciled with Beil’s name was washed up on the beach.

An engineering test pilot for Lockheed, Beil was a veteran of the war in Vietnam, the spokesman said.

The helicopter took off from the company’s test facility at the Ventura County Airport in Oxnard. It had been making flights over the coast for about two months.

Los Angeles Times, Thursday, 13 March 1969, Part II, Page 8, Columns 1–2

A prototype Lockheed AH-56A Cheyenne compound helicopter, just northwest of Ventura County Airport (now, Oxnard Airport, OXR), Oxnard, California, circa 1969. (Lockheed Martin)

A U.S. Army investigation found that while flying at a speed of 190 knots the helicopter’s main rotor blades began oscillating up to 3 feet vertically at the tips, and struck both the tail boom and the cockpit. In a 7 October 1969 article, the Los Angeles Times wrote:

When the blades dipped that low, they sliced through the fuselage both ahead of and behind the blade pylon. When they sliced through the fuselage forward of the pylon on which they were mounted, they struck the body of pilot Beil, the report indicated.

David A. Beil had been copilot of Dawdling Dromedary, a U.S. Navy Sikorsky SH-3A Sea King which flew from the aircraft carrier USS Hornet (CVS-12) at San Diego, California, to the USS Franklin D. Roosevelt (CVA-42) at Mayport, Florida, non-stop, 6 March 1965. (See TDiA, 6 March 1965)

A Lockheed AH-56A Cheyenne firing rockets during flight testing. (U.S. Army)

The Lockheed AH-56A Cheyenne was a two-place, single-engine, compound helicopter, developed by the Lockheed-California Company for the United States Army. Ten prototypes were built at Lockheed’s plant at Van Nuys Airport (VNY). It had a four-bladed rigid main rotor, a stub wing, a four-bladed tail rotor and a three-bladed pusher propeller.

The Cheyenne is 54 feet, 8 inches long, and 13 feet, 8.5 inches high. The main rotor has a diameter of 51 feet, 3 inches. The prototype empty weight is 12,215 pounds, and maximum takeoff weight is 25,880 pounds.

© 2022, Bryan R. Swopes