Tag Archives: Aircraft Accident

22 May 1968

Los Angeles Airways’ Sikorsky S-61L N300Y at Disneyland Heliport, Anaheim, California. This is the sister ship of N303Y, and it would also be destroyed in a catastrophic accident, 14 August 1968. (Sikorsky Historical Archives)
Los Angeles Airways’ Sikorsky S-61L N300Y at Disneyland Heliport, Anaheim, California. This is the prototype S-61L and the sister ship of N303Y. It would also be destroyed in a catastrophic accident, 14 August 1968. (Sikorsky Historical Archives)

22 May 1968: Los Angeles Airways Flight 841, a Sikorsky S-61L, N303Y, was enroute from Disneyland, Anaheim, California, to Los Angeles international Airport (LAX). Captain John E. Dupies and First Officer Terry R. Herrington were in the cockpit, while Flight Attendant Donald P. Bergman was in the passenger cabin with twenty passengers. The flight was cruising on a westerly heading at 2,000 feet (610 meters) when the five main rotor blades “underwent a series of extreme over-travel excursions in their lead/lag axis.”

The five main rotor blades are identified by color markings: red, black, white, yellow and blue (clockwise as seen from above). As the black blade oscillated fore and aft, the geometry of the pitch change control rods to the blades changed, rapidly varying the blades’ pitch angles and therefore, the lift and drag they produced. This put extreme overloads on the pitch control rods and and the rod controlling the yellow blade failed. The yellow blade was no longer in control. The extreme dynamic changes in the blade’s motion was transmitted to the white blade which also went out of control, followed by the other three blades. All five blades diverged from the normal tip-path plane and began to strike each other and the helicopter’s fuselage. The yellow blade was driven out of its normal sequence between the white and blue blades and struck the fuselage at the baggage door with its top flat against the fuselage side. It broke into five sections then wrapped around the rotor mast. All blades were destroyed. The helicopter, completely out of control, fell nearly vertically to the ground. The crew radioed, “L.A., we’re crashing. Help us.”

At 5:51 p.m., Pacific Daylight Time, Flight 841 crashed on Alondra Boulevard near Minnesota Street in the city of Paramount. The aircraft was completely destroyed by the impact and post-crash fire. All 23 persons on board were killed.

The crash scene of Los Angeles Airways Flight 841, along Alondra Blvd, Paramount, California, 22 May 1968. One main roto rblade can be seen protruding from a building's roof, nearby. (Unattributed)
The crash scene of Los Angeles Airways Flight 841, along Alondra Blvd, Paramount, California, 22 May 1968. One main rotor blade can be seen on a building’s roof, nearby. (Unattributed)

The National Transportation Safety Board (NTSB) investigation determined that the probable cause of the accident was a failure of the black blade’s lead/lag hydraulic damper or a loss of effectiveness of the white blade’s damper. The reason for this failure was not determined.

Captain “Jack” Dupies was a veteran pilot with Los Angeles Airways, having worked for the airline since 1953. He had a total of 12,096 flight hours with 4,208 hours in the S-61. First Officer Herrington had a total of 872 flight hours with 589 hours in helicopters. He had joined Los Angeles Airways in January 1968.

Sikorsky S-61L N303Y, s/n 61060, was completed in June 1962. At the time of the crash, it had accumulated 11,128 total hours on the airframe. It had undergone a complete 2,400-hour overhaul approximately 6 months earlier.

The Sikorsky S-61L was a civil variant of the United States Navy HSS-2 Sea King, and was the first helicopter specifically built for airline use. The prototype, N300Y, first flew 2 November 1961. It is a large twin-engine helicopter with a single main rotor/tail rotor configuration. Although HSS-2 fuselage is designed to allow landing on water, the S-61L is not amphibious, having standard fixed landing gear rather than the sponsons of the HSS-2 (and civil S-61N). The S-61L fuselage is 4 feet, 2 inches (1.270 meters) longer than that of the HSS-2. The S-61L is 72 feet, 7 inches (22.123 meters) long and 16 feet, 10 inches (5.131 meters) high, with rotors turning.

The main rotor has five blades and a diameter of 62 feet (18.898 meters). Each blade has a chord of 1 foot, 6.25 inches (0.464 meters). The tail rotor also has five blades and a diameter of 10 feet, 4 inches (3.149 meters). They each have a chord of 7–11/32 inches (0.187 meters). At 100% r.p.m., the main rotor turns 203 r.p.m. and the tail rotor, 1,244 r.p.m. The main rotor turns counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right side.) The tail rotor turns clockwise, as seen from the left side. (The advancing blade is below the axis of rotation.)

N303Y was powered by two General Electric CT58-140-1 engines. The CT58 is an axial-flow free-turbine turboshaft engine with a 10-stage compressor section and a 3-stage turbine (2 low- and 1 high-pressure stages). The -140-1 is rated at 1,400 shaft horsepower for takeoff and 1,500 SHP for 2½ minutes, with one engine inoperative. The compressor turns 26,300 r.p.m. (100% N1) and the power turbine, 19,500 r.p.m. (100% N2). The CT58-140-1 is 1 foot, 8.2 inches (0.513 meters) in diameter, 4 feet, 11.0 inches (1.499 meters) long and weighs 350 pounds (158.8 kilograms).

The helicopter’s main transmission was rated for 2,300 horsepower, maximum.

The S-61 has a cruise speed of 166 miles per hour (267 kilometers per hour). The service ceiling is 12,500 feet (3,810 meters). The maximum takeoff weight is 20,500 pounds (9,298.6 kilograms).

Between 1958 and 1980, Sikorsky built 794 S-61 series helicopters. 13 were S-61Ls. As of September 2013, two remained in service.

Diagram of Sikorsky S-61L rotor head. (NTSB)
Diagram of Sikorsky S-61L rotor head. (NTSB)

© 2018, Bryan R. Swopes

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19 May 1934–18 May 1935

Tupolev ANT-20 eight-engine civil transport. (Tupolev)
M.M. Gromov

19 May 1934: Soviet test pilot Mikhail Mikhaylovich Gromov made the first flight of the Tupolev ANT-20 Maxim Gorky. This was the largest airplane of its time. Designed by Andrei Tupolev to carry 72 passengers, the giant airplane was operated by eight crew members.

Used primarily as a Soviet propaganda tool, it also carried a powerful broadcast radio station, a printing shop, and loudspeakers.

Constructed of corrugated sheet metal for rigidity and strength, the ANT-20 was 107 feet, 11¼ inches (32.899 meters) long, with a wingspan of 206 feet, 8¼ feet inches (62.998 meters) and height of 34 feet, 9¼ inches (10.598 meters). Its empty weight was 62,700 pounds (28,440.2 kilograms) and the maximum takeoff weight was 116,600 pounds (52,888.9 kilograms)

Tupolev ANT-20 six-engine civil transport. Two additional engines would be added later. (Tupolev)

The ANT-20 was powered by eight liquid-cooled, supercharged, 2,896.1-cubic-inch-displacement (46.928 liter) Mikulin AM-34FRN single overhead cam (SOHC) 60° V-12 engines, rated at 1,200 horsepower at 2,000 r.p.m., each. They drove two-bladed propellers. Two of the engines were mounted above the fuselage, in a push-pull configuration.

This photograph shows the corrugated sheet metal used for the skin of the ANT-20's wings and fuselage.
Corrugated sheet metal was used for the skin of the ANT-20’s wings and fuselage.

Maxim Gorky had a maximum speed of 137 miles per hour (220.5 kilometers per hour), a service ceiling of 4,500 meters (14,764 feet) and a range of 750 miles (1,207 kilometers).

Just 364 days after its first flight, 18 May 1935, Maxim Gorky crashed following a mid-air collision during a formation flight over Moscow. 45 people were killed.

The ANT-20 flies over Red Square with an airplane off each wing.
M.M. Gromov, 1917

Mikhail Mikhaylovich Gromov was born 24 February 1899, at Tver, about 110 miles (180 kilometers) northwest of Moscow. He was the son of Mikhail Konstantinovich Gromov, an “intellectual” who had studied medicine at Moscow University, and Lyubov Ignayevna Gromov, a midwife. The family were of the nobility, but poor.

The younger Gromov attended the Resurrection Real School, and then the Moscow Higher Technical School for Aviation. He graduated in 1917. Gromov was taught to fly by Boris Konstantinovich Welling, a pioneer in Russian long-distance flights. After working as a flight instructor, Gromov began test flying. He became the chief test pilot for the Tupolev Design Bureau. By the outbreak of World War II, he had test flown twenty-five different airplanes.

In 1926, Gromov made a non-stop long-distance flight in a Tupolev ANT-3, from Moscow via Berlin, Paris, Rome, Vienna, Prague, Warsaw and back to Moscow. The flight took 34 hours. In 1934, he flew a Tupolev ANT-25 12,411 kilometers (7,712 miles) in a closed circuit over 75 hours. For this accomplishment, he was named a Hero of the Soviet Union.

From 12–14 July 1937, Gromov set a world record for distance in a straight line, flying an ANT-25 from Moscow to San Jacinto, California, a distance of 10,148 kilometers (6,306 miles).¹ The duration of this flight was 62 hours, 17 minutes.

n March 1941, Gromov became the first director of the Flight Research Institute at Zhukovsky, southeast of Moscow. The Institute was later named the M.M. Gromov Flight Research Institute, in his honor.

In 1942, during The Great Patriotic War, Gromov commanded the Soviet long range air forces on the Kalinin Front. He next commanded the 3rd Air Army, 1942–1943, and the 1st Air Army, 1943–1944. In 1945, he returned to test flying.

Colonel General Mikhail Mikhaylovich Gromov, 1946

Following the War, Gromov continued to work in the aviation industry, but following a disagreement with the Minister of Aviation, Pyotr Vasilyevich Dementiev, over the issue of quality vs. quantity and the safety of the test pilots, he retired. Later, he entered politics and was twice elected to the Supreme Soviet.

During his military career, in addition to the Gold Star Medal of Hero of the Soviet Union, Colonel General Mikhail Mikhaylovich Gromov was awarded the Order of Lenin four times, the Order of the Red Banner (four), and the Order of the Red Star (three). He died 22 January 1985.

¹ FAI Record File Number 9300

© 2018, Bryan R. Swopes

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18 May 1961

Commander Jack L. Felsman and Ensign Raymond F. Hite, Jr., in the cockpit of their McDonnell F4H-1F Phantom II.
Commander Jack L. Felsman and Ensign Raymond M. Hite, Jr., in the cockpit of their McDonnell F4H-1F Phantom II. (United States Navy)

18 May 1961: Operation SAGE BURNER, one of a series of record-setting flights intended to commemorate the 50th anniversary of United States Naval Aviation, ended tragically when a McDonnell F4H-1F Phantom II, Bu. No. 145316, crashed during a low-altitude supersonic speed run at the White Sands Missile Range near Holloman Air Force Base, New Mexico.

Commander Jack Lee Felsman and Ensign Raymond Maxwell Hite, Jr., were killed and their Phantom was destroyed when a pitch damper failed, which resulted in Pilot Induced Oscillation. The uncontrolled oscillations became so severe that the Phantom’s airframe was subjected to 12 gs, causing it to break apart in flight. Both engines were torn from the airframe.

This was the first fatal accident involving the Phantom II.

SAGE BURNER, McDonnell F4H-1F Phantom II, Bu. No. 145316
SAGE BURNER, McDonnell F4H-1F Phantom II, Bu. No. 145316. The object on the centerline hardpoint appears to be a Mark 43 weapon.
Sage Burner, McDonnell F4H-1F Phantom II, Bu. No. 145316
McDonnell F4H-1F Phantom II, Bu. No. 145316 with B-61 bomb on centerline hardpoint.

A video clip showing the inflight break up can be seen on YouTube at

Jack Lee Felsman was born 4 April 1923, the second of two children Charles Edward Felsman, a farmer, and Vera McKay Felsman.

Jack Felsman entered the United States Navy 12 December 1942. He was trained as a pilot and commissioned an Ensign, United States Navy 4 September 1943. He was promoted to Lieutenant (j.g.), 1 February 1945. He was promoted to Lieutenant, 15 July 1951, and to Lieutenant Commander, 1 August 1956. Felsman was married to Miss Hallie May McKay.

Commander Felsman’s remains were buried at the Rock Island National Cemetery, Rock Island, Illinois.

Raymond Maxwell Hite, Jr., was born 3 December 1927 in Los Angeles County, California, the son of Raymond Maxwell Hite and Elizabeth Ball Hite. Ensign Hite’s remains were interred at the Roselawn Burial Park, Martinsville, Virginia.

© 2017, Bryan R. Swopes

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16 May 1977

Sikorsky S-61L N619PA
New York Airways’ Sikorsky S-61L, N916PA. (Photograph by Stefan Sjögren, used with permission.)

16 May 1977: At approximately 5:32 p.m. Eastern Standard Time, New York Airways Flight 971, a Sikorsky S-61L helicopter, landed at the Pan Am Building rooftop heliport (JPB) in New York City. Flight 971 had originated at John F. Kennedy International Airport (JFK) and carried 20 passengers and a crew of three. The helipad was 855.23 feet (260.67 meters) above Sea Level.

In the cockpit’s right seat was Captain Lee G. Richmond. Captain Richmond had 11,721 total flight hours with over 9,000 in helicopters and approximately 2,200 in the Sikorsky S-61. He had worked for New York Airways since 1964. The co-pilot was First Officer John F. Flanagan had worked for NYA for about five weeks. He had 1,768.4 flight hours with 1,339.2 hours in helicopters. Both pilots had flown 3 hours, 33 minutes on 16 May. Flight Attendant Lammie Chevalier had been employed by NYA for four years.

A Sikorsky S-61L hovers over the Pan Am Building heliport. (Unattributed)
A New York Airways Sikorsky S-61L hovers over the Pan Am Building heliport. (Pan Am)

Captain Richmond taxied the S-61 into position on the 131-foot × 131-foot (39.9 × 39.9 meters) concrete helipad. While parked at the gate, Richmond kept the rotors turning at 100%, keeping the cyclic control centered and the collective full down (negative pitch). The Automatic Flight Control System (AFCS) was engaged. Flanagan kept his left knee against the collective pitch lever to ensure that it remained full down. Flight Attendant Chevalier stood inside the passenger cabin, supervising departing and boarding passengers.

The return flight to JFK was designated Flight 972.

Aerial photo of the wreck of Flight 972 atop the Pan Am Building, 16 May 1977. (Neal Boenzi/The New York Times)
Aerial photo of the wreck of Flight 972 atop the Pan Am Building, 16 May 1977. (Neal Boenzi/The New York Times)

2 minutes, 21 seconds after touch down, at approximately 5:35 p.m., the right main landing gear of the helicopter failed and the S-61 rolled over to the right. All main rotor blades struck the concrete helipad. Four passengers who were waiting to board were struck by the blades and killed. One of the blades, 28 feet, 10 inches (8.787 meters) long and weighing 209.3 pounds (94.9 kilograms) flew out over the building’s railing and fell alongside the building before crashing through an office window on the 36th floor. The main rotor blade broke into two segments, one of which fell to the street below, striking a pedestrian and killing him. Additional pieces of the main rotor blades were found up to four blocks north of the Pan Am Building.

Wreck of S-61L N619PA at the Pan Am Building rooftop heliport, 16 May 1977. (Unattributed)
Wreck of S-61L N619PA at the Pan Am Building rooftop heliport, 16 May 1977. The Chrysler Building is in the background. (Unattributed)

The helicopter assigned to Flight 971/972 was a Sikorsky S-61L, s/n 61427, registered N619PA. At the time of the accident, the helicopter had a total of 6,913:15 hours on the airframe. Just 7 hours, 22 minutes had elapsed since the last major inspection.

The National Transportation Safety Board (NTSB) investigation determined that the probable cause of the accident was: “. . . the fatigue failure of the upper right forward fitting of the right main landing gear tube assembly. Fatigue originated from a small surface pit of undetermined source. All fatalities were caused by the operating rotor blades as a result of the collapse of the landing gear.”

The NTSB determined that the flight crew had performed correctly, and that the aircraft was properly certified, maintained and operated. The Board speculated that the four boarding passengers would have been killed by the helicopter rolling over, even if the engines had been shut down and rotors stopped.

Sikorsky S-61L N619PA lies on its right side at the Pam Am Building heliport, May 1977. The Empire State Building is in the background. (Unattributed)
Sikorsky S-61L N619PA lies on its right side at the Pam Am Building heliport, May 1977. The Empire State Building is in the background. (Unattributed)

A similar accident had occurred when a Los Angeles Helicopters Sikorsky S-61L suffered a fatigue fracture of its right landing gear and rolled over at Los Angeles International Airport (LAX) in 1963. This accident had resulted in a change in the material used to manufacture the parts.

The Sikorsky S-61L was a civil variant of the United States Navy HSS-2 Sea King, and was the first helicopter specifically built for airline use. The prototype, N300Y, first flew 2 November 1961. It is a large twin-engine helicopter with a single main rotor/tail rotor configuration. Although HSS-2 fuselage is designed to allow landing on water, the S-61L is not amphibious, having standard fixed landing gear rather than the sponsons of the HSS-2 (and civil S-61N). The S-61L fuselage is 4 feet, 2 inches (1.270 meters) longer than that of the HSS-2. The S-61L is 72 feet, 7 inches (22.123 meters) long and 16 feet, 10 inches (5.131 meters) high, with rotors turning.

The main rotor has five blades and a diameter of 62 feet (18.898 meters). Each blade has a chord of 1 foot, 6.25 inches (0.464 meters). The tail rotor also has five blades and a diameter of 10 feet, 4 inches (3.149 meters). They each have a chord of 7–11/32 inches (0.187 meters). At 100% r.p.m., the main rotor turns 203 r.p.m. and the tail rotor, 1,244 r.p.m. The main rotor turns counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right side.) The tail rotor turns clockwise, as seen from the left side. (The advancing blade is below the axis of rotation.)

N619PA was powered by two General Electric CT58-140-2 turboshaft engines, each of which had maximum power rating of 1,400 shaft horsepower for takeoff and 1,500 SHP for 2½ minutes. The main transmission was rated for 2,300 horsepower, maximum.

The S-61 has a cruise speed of  166 miles per hour (267 kilometers per hour). The service ceiling is 12,500 feet (3,810 meters). The maximum takeoff weight is 20,500 pounds (9,298.6 kilograms).

Between 1958 and 1980, Sikorsky built 794 S-61 series helicopters. 13 were S-61Ls. As of May 2017, two remained in service.

© 2018, Bryan R. Swopes

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12 May 1953

Jean L. "Skip" Ziegler, with the Bell X-5 at Edwards Air Force Base, 1952. (LIFE Magazine via Jet Pilot Overseas.
Jean L. “Skip” Ziegler, with a Bell X-5 at Edwards Air Force Base, 1952. (LIFE Magazine via Jet Pilot Overseas)

12 May 1953: A Boeing B-50A-5-BO Superfortress, 46-011, modified to carry a Bell X-2 supersonic research rocketplane, was engaged in a captive test flight at 30,000 feet (9,144 meters) over Lake Ontario, between Canada and the United States. The number two X-2, 46-675, was in the bomb bay.

The bomber was equipped with a system to keep the X-2’s liquid oxygen tank filled as the cryogenic oxidizer boiled off. With Bell’s Chief of Flight Research, test pilot Jean Leroy (“Skip”) Ziegler, in the bomb bay above the X-2, the system operation was being tested.

There was an explosion. The X-2 fell from the bomber and dropped into Lake Ontario, between Trenton, Ontario, Canada, and Rochester, New York, U.S. A. Skip Ziegler and an engineer aboard the bomber, Frank Wolko, were both lost. A technician, Robert F. Walters, who was in the aft section of the B-50 with Wolko, was badly burned and suffered an injured eye.

The B-50’s pilots, William J. Leyshon and David Howe, made an emergency landing at the Bell Aircraft Corporation factory airport at Wheatfield, New York (now, the Niagara Falls International Airport, IAG). The bomber was so heavily damaged that it never flew again.

Heavy fog over the lake hampered search efforts. Neither the bodies of Ziegler and Wolko or the wreckage of the X-2 were found.

A Bell X-2 rocketplane is loaded aboard the Boeing B-50A Superfortress "mothership," 46-011. (U.S. Air Force)
A Bell X-2 rocketplane is loaded aboard the Boeing B-50A-5-BO Superfortress “mothership,” 46-011. (U.S. Air Force)

After a series of explosions of early rocketplanes, the X-1A, X-1-3, X-1D and the X-2,  investigators discovered that leather gaskets which were used in the fuel system had been treated with tricresyl phosphate (TCP). When this was exposed to liquid oxygen an explosion could result. The leather gaskets were removed from the other rocketplanes and the explosions stopped.

The X-2 was a joint project of the U.S. Air Force and NACA (the National Advisory Committee on Aeronautics, the predecessor of NASA). The rocketplane was designed and built by Bell Aircraft Corporation of Buffalo, New York, to explore supersonic flight at speeds beyond the capabilities of the earlier Bell X-1 and Douglas D-558-II Skyrocket. Two X-2s were built.

In addition to the aerodynamic effects of speeds in the Mach 2.0–Mach 3.0 range, engineers knew that the high temperatures created by aerodynamic friction would be a problem, so the aircraft was built from stainless steel and K-Monel, a copper-nickel alloy.

The Bell Aircraft Corporation X-2 was 37 feet, 10 inches (11.532 meters) long with a wingspan of 32 feet, 3 inches (9.830 meters) and height of 11 feet, 10 inches (3.607 meters). Its empty weight was 12,375 pounds (5,613 kilograms) and loaded weight was 24,910 pounds (11,299 kilograms).

The X-2 was powered by a throttleable two-chamber Curtiss-Wright XLR25-CW-1 rocket engine that produced 2,500–15,000 pounds of thrust (11.12–66.72 kilonewtons)

Boeing EB-50D Superfortress 48-096 with a Bell X-2 (U.S. Air Force)

Rather than use its limited fuel capacity to take off and climb to altitude, the X-2 was dropped from a modified heavy bomber as had been the earlier rocketplanes.

The launch altitude was 30,000 feet (9,144 meters). After the fuel was exhausted, the X-2 glided to a touchdown on Rogers Dry Lake at Edwards Air Force Base.

The X-2 reached a maximum speed of Mach 3.196 (2,094 miles per hour/3,370 kilometers per hour) and maximum altitude of 126,200 feet (38,466 meters).

Bell X-2 46-675 on its transportation dolly at Edwards Air Force Base, California, 1952. (NASA)
Bell X-2 46-675 on its transportation dolly at Edwards Air Force Base, California, 1952. (NASA)

© 2017, Bryan R. Swopes

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