Tag Archives: Sikorsky Aircraft Corporation

14 August 1968

Sikorsky S-61L N300Y, Los Angeles Airways, at Disneyland Heliport, Anaheim, California. (Robert Boser)
Sikorsky S-61L N300Y, Los Angeles Airways, at Disneyland Heliport, Anaheim, California. (Robert Boser)

14 August 1968: At 10:28:15 a.m., Pacific Daylight Time, Los Angeles Airways Flight 417, a Sikorsky S-61L helicopter, departed Los Angles International Airport (LAX) on a regularly-scheduled passenger flight to Disneyland, Anaheim, California. On board were a crew of three and eighteen passengers. The aircraft commander, Captain Kenneth L. Waggoner, held an Airline Transport Pilot certificate and was type-rated in the Sikorsky S-55, S-58 and S-61L. He had a total of 5,877:23 flight hours, with 4,300:27 hours in the S-61L. Co-pilot F. Charles Fracker, Jr. had 1,661:18 flight hours, of which 634:18 were in the S-61L. Flight Attendant James A. Black had been employed with LAA for nearly ten years.

At approximately 10:35 a.m., while flying at an estimated altitude of 1,200–1,500 feet (370–460 meters) above the ground, one of the helicopter’s five main rotor blades separated from the aircraft which immediately went out of control, started to break up, and crashed in a recreational park in Compton. All twenty-one persons on board, including the 13-year-old grandson of the airlines’ founder and CEO, were killed.

The Sikorsky S-61 was registered N300Y.  It had been the prototype S-61L, serial number 61031. Los Angeles Airways was the first civil operator of the S-61, purchasing them at a cost of $650,000 each. As of the morning of 14 August 1968, 61031 had accumulated a total of 11,863.64 hours flight time on the airframe (TTAF). It flew an estimated 3.17 hours on the morning of the accident.

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 S-61L was powered by two General Electric CT58-140-1 turboshaft engines, each of which was rated for 1,400 shaft horsepower for takeoff and maximum power of 1,500 shaft horsepower 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). 61031 had a maximum takeoff weight (MTOW) of 19,000 pounds (8,618.3 kilograms).

Between 1958 and 1980, Sikorsky built 794 S-61 series helicopters. 13 were S-61Ls.

The National Transportation Safety Board investigation found that most of the helicopter was contained with a small area of Leuders Park. One main rotor blade, however, was located approximately 0.25 miles (0.40 kilometers) west of the main wreckage. This blade is referred to as the “yellow” blade. (The main rotor blades marked with colored paint for simplicity, red, black, white, yellow, and blue.) Analysis found that this blade’s spindle, where it attached to the main rotor hub assembly, had failed due to a fatigue fracture. It was believed that the fracture began in an area of substandard hardness which was present in the original ingot from which the part was forged, and that inadequate shot-peening of the part during the overhaul process further weakened the spindle.

Diagram of fractured main rotor spindle. (NTSB)
Diagram of fractured main rotor spindle. (NTSB)

Los Angeles Airways had experienced a similar accident only three months earlier which had resulted in the deaths of all 23 persons on board. (Flight 841, 22 May 1968). L.A. Airways never recovered and ceased all operations by 1971.

© 2016, Bryan R. Swopes

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3 July 1951: Medal of Honor, Lieutenant (j.g.) John Kelvin Koelsch, United States Navy

Lieutenant (j.g.) John Kelvin Koelsch, United States Navy.
Lieutenant (Junior Grade) John Kelvin Koelsch, United States Navy.
Medal of Honor Citation for Lt. (j.g.) John K. Koelsch, U.S.N. (National Archives)
Medal of Honor Citation for Lt. (j.g.) John K. Koelsch, U.S.Navy. (National Archives)

3 July 1951: With his Vought F4U-4B Corsair, Bu. No. 63056, hit and on fire, Captain James V. Wilkins, United States Marine Corps, of Marine Fighter Squadron 312 (VMF-312) stationed aboard USS Sicily (CVE-118), bailed out approximately 35 miles (56 kilometers) southeast of Wonson, North Korea. He parachuted onto a mountainside in the Anbyon Valley.

Severely burned and with an injured leg, Captain Wilkins was seen by North Korean soldiers along a heavily-travelled supply route. While enemy soldiers shot at him, Wilkins tried to escape by crawling up the mountainside.

A U.S. Marines F4U Corsair of VMF-312 about to land aboard an aircraft carrier during the Korean War. This is the same type fighter flown by Captain. J.V. Wilkins on 3 July 1951. (U.S. Navy)
A U.S. Marines F4U Corsair of VMF-312 about to land aboard an aircraft carrier during the Korean War. This is the same type fighter flown by Captain. J.V. Wilkins on 3 July 1951. (U.S. Navy)

Lieutenant (j.g.) John Kelvin Koelsch, United States Navy, was a helicopter pilot in charge of a detachment of Helicopter Utility Squadron Two (HU-2), stationed aboard a former U.S. Navy Landing Ship (Tank), USS LST-488. The LST had been transferred to Japan after World War II and converted to a merchant ship. During the Korean War, it and its 45-man Japanese crew were contracted to the U.S. Navy. The LST was reconverted to a helicopter support ship, designated Q-009.

A torpedo bomber pilot during World War II, Lieutenant Koelsch transferred to Helicopter Utility Squadron One (HU-1) at NAS Lakehurst, New Jersey, in 1949, and was trained to fly the Sikorsky HO3S-1 helicopter, a Navy variant of the commercial Sikorsky S-51. He had completed a combat tour aboard USS Princeton (CV-37) but rather than return to the United States with his squadron, requested a transfer to HU-2. Koelsch told his shipmates that he felt rescuing downed pilots was his mission.

A U.S. Navy Sikorsky HO3S-1, possibly Bu. No. 122715, rescues a downed flyer from Wonson Harbor, 1951. (Sikorsky Historical Archives)
A U.S. Navy Sikorsky HO3S-1, possibly Bu. No. 122715, rescues a downed flyer from Wonson Harbor, 1951. (Sikorsky Historical Archives)

When Captain Wilkins’ Corsair went down, Lieutenant Koelsch volunteered to attempt a rescue. Shortly before sunset, he and his rescue crewman, Aviation Machinist’s Mate 3rd Class George Milton Neal, boarded their helicopter, Sikorsky HO3S-1, Bu. No. 122715, and took off from Q-009 in a mist and low clouds.

Lieutenant Koelsch's Sikorsky HO3-S-1 helicopter, Bu. No. 122715, aboard USS Phillipine Sea (CV-47). (U.S. Navy)
Lieutenant Koelsch’s Sikorsky HO3-S-1 helicopter, Bu. No. 122715, aboard USS Philippine Sea (CV-47). (U.S. Navy)

Wilkins heard Koelsch’s helicopter approaching and moved back down the mountain toward his parachute. He saw the Sikorsky flying at about 50 feet (15 meters) below a layer of clouds. The helicopter was receiving heavy ground fire from the North Korean soldiers along the road. The Sikorsky was hit and Koelsch turned away, but quickly returned. Koelsch located Wilkins and brought the HO3S-1 to a hover while rescue crewman Neal lowered a “horse collar” harness on a hoist cable. Neal then lifted the fighter pilot up to the helicopter.

The helicopter continued to be targeted by ground fire and it was finally shot down. 122715 crashed on the mountainside and rolled upside down. Koelsch and Neal were unhurt and Wilkins suffered no new injuries. Koelsch and Neal carried Wilkins and they moved away from the enemy forces, heading toward the coast. The three Americans evaded the enemy for nine days before they were captured.

John Koelsch refused to cooperate with his captors. He was held in isolation and subjected to torture. He refused to give in but soon became very ill. Just three months after being captured, Lieutenant (j.g.) John Kelvin Koelsch died. For his actions during and after 3 July 1951, he was awarded the Medal of Honor.

Captain Wilkins and AM3 Neal survived the war and were eventually returned to the United States. George Milton Neal was awarded the Navy Cross.

In 1968, the Garcia-class frigate USS Koelsch (FF-1049) was named in honor of the first helicopter pilot to be awarded the Medal of Honor.

USS Koelsch (FF-1049). (U.S. Navy)
USS Koelsch (FF-1049), a Garcia-class frigate. (U.S. Navy)

© 2016, Bryan R. Swopes

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31 May–1 June 1967

Left to Right: Major Herbert Zehnder, USAF; Igor Sikorsky; Major Donald B. Murras, USAF, at Le Bourget, 1 June 1967.
Major Herbert R. Zehnder, USAF; Igor Sikorsky; Major Donald B. Murras, USAF, at le Bourget, 1 June 1967. (Sikorsky Historical Archives)

At 0105 hours, 31 May 1967, two Sikorsky HH-3E Jolly Green Giant helicopters, 66-13280 and 66-13281, from the 48th Aerospace Rescue and Recovery Squadron, United States Air Force, took off from Floyd Bennett Field, New York and flew non-stop across the Atlantic Ocean to the Paris Air Show. They arrived at Le Bourget at 1351 hours, 1 June.

The flight covered 4,271 miles (6873.5 kilometers) and took 30 hours, 46 minutes. Nine in-flight refuelings were required from Lockheed HC-130P Combat King tankers. The aircraft commanders were Major Herbert Zehnder and Major Donald B. Murras.

Major Zehnder, in H-211, set a Fédération Aéronautique Internationale (FAI) World Record for Speed Over a Recognized Course for helicopters, with an average speed of 189.95 kilometers per hour (118.03 miles per hour). This record still stands.¹

One of two 48th ARRS Sikorsky HH-3E Jolly Green Giant lands at Le Bourget after non-stop trans Atlantic flight, 1 June 1967. (Louisiana State Museum)
“H-211,” one of two 48th ARRS Sikorsky HH-3E Jolly Green Giant helicopters, lands at Le Bourget after a non-stop trans Atlantic flight, 1 June 1967. (Louisiana State Museum)
Lieutenant Colonel Travis Wofford, United States Air Force.
Lieutenant Colonel Travis Wofford, United States Air Force.

Both Jolly Green Giants, serial numbers 66-13280 and 66-13281, were later assigned to the 37th Air Rescue and Recovery Squadron. Both were lost in combat during the Vietnam War.

66-13280, “Jolly Green 27” crashed at Kontum, Republic of South Vietnam, 15 April 1970. The pilot, Captain Travis H. Scott, Jr., was killed, and flight engineer Gerald E. Hartzel later died of wounds. The co-pilot, Major Travis Wofford, was awarded the Air Force Cross and the Cheney Medal for his rescue of the crewmembers from the burning helicopter. Captain Scott was posthumously awarded the Air Force Cross.

66-13281, “Jolly Green 28,” was shot down over Laos, 24 October 1969. The crew was rescued and the helicopter destroyed to prevent capture. The pararescueman, Technical Sergeant Donald G. Smith, was awarded the  Air Force Cross for the rescue of the pilot of “Misty 11.” He was also awarded the Airman’s Medal.

Master Sergeant Donald G. Smith, United States Air Force.
Master Sergeant Donald G. Smith, United States Air Force.

Major Herbert Zehnder flew another Sikorsky HH-3E, 65-12785, to intentionally crash land inside the Sơn Tây Prison Camp, 23 miles (37 kilometers) west of Hanoi, North Vietnam. He was awarded the Silver Star.

The SH-3A Sea King (Sikorsky S-61) first flew 11 March 1959, designed as an anti-submarine helicopter for the U.S. Navy. The prototype was designated XHSS-2 Sea King. In 1962, the HSS-2 was redesignated SH-3A Sea King. Many early production aircraft were upgraded through SH-3D, SH-3G, etc. In addition to the original ASW role, the Sea Kings have been widely used for Combat Search and Rescue operations. Marine One, the call sign for the helicopters assigned to the President of the United States, are VH-3D Sea Kings.

A Sikorsky HH-3E Jolly Green Giant (66-13290) of the 37th Air Rescue and Recovery Squadron, hovering in ground effect at Da Nang, Republic of South Vietnam, 1968. (U.S. Air Force)

The Sikorsky HH-3E (Sikorsky S-61R) earned the nickname Jolly Green Giant during the Vietnam War. It is a dedicated Combat Search and Rescue (CSAR) helicopter flown by the U.S. Air Force, based on the CH-3C transport helicopter. The aircraft is flown by two pilots and the crew includes a flight mechanic and gunner. It is a large twin-engine helicopter with a single main rotor/tail rotor configuration. It has retractable tricycle landing gear and a rear cargo ramp. The rear landing gear retracts into a stub wing on the aft fuselage. The helicopter has an extendable inflight refueling boom.

The HH-3E is 72 feet, 7 inches (22.123 meters) long and 18 feet, 10 inches (5.740 meters) high with all 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 main rotor turns at 203 r.p.m., counter-clockwise, as seen from above. (The advancing blade is on the right.) The tail rotor also has five blades and has a diameter of 10 feet, 4 inches (3.150 meters). The blades have a chord of 7–11/32 inches (0.187 meters). The tail rotor turns clockwise as seen from the helicopter’s left. (The advancing blade is below the axis of rotation.) The tail rotor turns 1,244 r.p.m.

A Sikorsky HH-3E Jolly Green Giant refuels in flight from a Lockheed HC-130 Combat King. (U.S. Air Force)
A Sikorsky HH-3E Jolly Green Giant refuels in flight from a Lockheed HC-130 Combat King. (U.S. Air Force)

The HH-3E has an empty weight of 13,341 pounds (6,051 kilograms). The maximum gross weight is 22,050 pounds (10,002 kilograms).

The Jolly Green Giant is powered by two General Electric T58-GE-5 turboshaft engines, which have a Maximum Continuous Power rating of 1,400 shaft horsepower, each, and Military Power rating of 1,500 shaft horsepower. The main transmission is rated for 2,500 horsepower, maximum.

The HH-3E has a cruise speed of 154 miles per hour (248 kilometers per hour) at Sea Level, and a maximum speed of 177 miles per hour (285 kilometers per hour), also at Sea Level. The service ceiling is 14,000 feet (4,267 meters). The HH-3E had a maximum range of 779 miles (1,254 kilometers) with external fuel tanks.

The Jolly Green Giant can be armed with two M60 7.62 mm machine guns.

Sikorsky built 14 HH-3Es. Many CH-3Cs and CH-3Es were upgraded to the HH-3E configuration. Sikorsky built a total of 173 of the S-61R series.

Sikorsky HH-3E Jolly Green Giant 67-14709 at the National Museum of the United States Air Force, Wright-Patterson Air Force Base, Ohio. (U.S. Air Force)
Sikorsky HH-3E Jolly Green Giant 67-14709 at the National Museum of the United States Air Force, Wright-Patterson Air Force Base, Ohio. (U.S. Air Force)

¹ FAI Record File Number 2092

© 2017, Bryan R. Swopes

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25 May 1889–26 October 1972

Igor Ivanovich Sikorsky, 1914. (Karl Karlovich Bulla)
Igor Ivanovich Sikorsky, 1914. Sikorsky is wearing the cross of the Imperial Order of St. Vladimir. (Karl Karlovich Bulla)

25 May 1889: И́горь Ива́нович Сико́рский (Igor Ivanovich Sikorsky) was born at Kiev, Russian Empire, the fifth of five children of Professor Ivan Alexeevich Sikorsky and Doctor Mariya Stefanovich Sikorskaya.

15 year-old Midshipman Igor Ivanovich Sikorksky, at lower right, with his sisters Olga, Lydia and Elena, and brother Sergei, 1904. (Sikorsky, a Lockheed Martin Company)
15 year-old Midshipman Igor Ivanovich Sikorksky, Imperial Naval Academy, at lower right, with his sisters Olga, Lydia and Elena, and brother Sergei, 1904. (Sikorsky, a Lockheed Martin Company)

He studied at the Imperial Naval Academy, St. Petersburg, from 1903 until 1906, when he left to study engineering, first in Paris, and then at the Kiev Polytechnic Institute.

Airplane pilot Igor Sikorsky with a passenger. (RIA Novosti)
Pilot Igor Ivanovich Sikorsky with a passenger, circa 1914. (RIA Novosti)

Flying an airplane of his own design, the S-5, on 18 April 1911, he received a Fédération Aéronautique Internationale pilot’s license from L’Aéro-Club Imperial de Russie (Imperial Russian Aero Club).

Igor I. Sikorsky's FAI pilot's license. (Sikorsky Historical Archives)
Igor I. Sikorsky’s FAI pilot’s license. (Sikorsky Historical Archives)

He was chief aircraft engineer for Russko-Baltiisky Vagonny Zavod at St. Petersburg and continued to develop airplanes. In 1913, he flew the twin engine S-21 Le Grand, to which he added two more engines, and it became the Russky Vityaz.

Igor Sikorsky with one of his early biplanes.
Igor Sikorsky with one of his early biplanes.
Sikorsky S-21 in flight
Sikorsky’s S-21 in flight, 1913

Igor Sikorsky married Olga Fyodorovna Simkovich. They had a daughter, Tania. The couple soon divorced, however.

Compagnie Générale Transatlantique liner, SS La Lorraine, 11,146 gross tons.
Compagnie Générale Transatlantique liner, SS La Lorraine, 11,146 gross tons.

Following the October Revolution, Sikorsky emigrated to the United States. Departing Le Havre, France, aboard SS La Lorraine, he arrived at New York on 31 March 1919. With financial backing from composer and conductor Sergei Vasilievich Rachmaninoff, he founded the Sikorsky Aero Engineering Company at Long Island, New York, in 1924, and continued designing and building airplanes.

In 1924, Sikorsky married Elisabeth Semion, who was also born in Russia, in 1903. They would have four children. In 1928, he became a citizen of the United States of America.

Sikorsky S-39 amphibian NC54V (Civil Air Patrol)
Sikorsky S-39 amphibian NC54V (Civil Air Patrol)

Beginning in 1934, Sikorsky Aircraft produced the S-42 flying boat for Pan American Airways at a new plant at Stratford, Connecticut.

U.S. Navy RS-1 (Sikorsky S-41) (National Museum of Naval Aviation)
U.S. Navy RS-1 (Sikorsky S-41) (National Museum of Naval Aviation)
A Pan American Airways Sikorsky S-42, NC16742, moored at Honolulu, Territory of the Hawaiian Islands. (hawaii.gov/hawaiiaviation)
Pan American Airways Sikorsky S-42, NC16734, moored at Honolulu, Territory of the Hawaiian Islands. (hawaii.gov/hawaiiaviation)

Interested in helicopters since the age of 9, he directed his creative effort toward the development of a practical “direct-lift” aircraft. The first successful design was the Vought-Sikorsky VS-300. Using a single main rotor, the VS-300 went through a series of configurations before arriving at the single anti-torque tail rotor design, the VS-316A. This was put into production for the U.S. military as the Sikorsky R-4.

The prototype VS-300 helicopter clears the ground for the first time, 14 September 1939. Igor Sikorsky is at the controls. His right foot rests on the anti-torque pedal. (Sikorsky Historical Archives)
The prototype VS-300 helicopter clears the ground for the first time, 14 September 1939. Igor Sikorsky is at the controls. His right foot rests on the anti-torque pedal. (Sikorsky Historical Archives)
Igor Sikorsky hovers the Vought-Sikorsky VS-300. (Sikorsky, a Lockheed Martin Company)
Igor Sikorsky hovers the Vought-Sikorsky VS-300A. (Sikorsky, a Lockheed Martin Company)
On behalf of the Fédération Aéronautique Internationale, the National Aeronautic Association of the United States issued Helicopter Pilot Certificate No. 1 to Igor I. Sikorsky, 10 December 1940. (Sikorsky Historical Archives)
On behalf of the Fédération Aéronautique Internationale, the National Aeronautic Association of the United States issued Helicopter Pilot Certificate No. 1 to Igor I. Sikorsky, 10 December 1940. (Sikorsky Historical Archives)
Igor Sikorsky in the cockpit of a production R-5 helicopter. (Sikorsky, a Lockheed Martin Company)
Igor Sikorsky in the cockpit of a Sikorsky S-48 (R-5) helicopter. (Sikorsky, a Lockheed Martin Company)

The company which Igor Sikorsky founded has continued as one of the world’s biggest helicopter manufacturers. Recently acquired by Lockheed Martin, Sikorsky continues to produce the UH-60-series of Blackhawk medium helicopters, the large CH-53K King Stallion, and the civil S-76D and S-92. A variant of the S-92 has been selected as the next helicopter for the U.S. presidential air fleet, the VH-92A. This helicopter is planned to be operational by 2020.

Igor Ivanovich Sikorsky died at Easton, Connecticut, 26 October 1972 at the age of 83 years.

Igor Sikorsky piloting his pontoon-equipped VS-300, 17 April 1941. (Sikorsky Historical Archives)
Igor Sikorsky piloting his pontoon-equipped VS-300, 17 April 1941. (Sikorsky Historical Archives)
s-47-4
Les Morris at the controls of the Vought-Sikorsky XR-4, 41-18874 (VS-316A), on its first flight at Stratford, Connecticut, 14 January 1942. (Sikorsky Historical Archives)
Lt. Carter Harman hovering in ground effect with Sikorsky YR-4B Hoverfly 43-28247 at Lalaghat, India, March 1944. This is the helicopter with which he made the first combat rescue, 21-25 April 1944. (U.S. Air Force)
Lt. Carter Harman hovering in ground effect with Sikorsky YR-4B Hoverfly 43-28247 at Lalaghat, India, March 1944. This is the helicopter with which he made the first combat rescue, 21-25 April 1944. (U.S. Air Force)
A Sikorsky R-5 flown by Jimmy Viner with Captain Jack Beighle, lifts a crewman from Texaco Barge No. 397, aground on Penfield Reef, 29 November 1945. (Sikorsky Historical Archive)
U.S. Army R-5 (Sikorsky S-48) flown by Jimmy Viner with Captain Jack Beighle, lifts a crewman from Texaco Barge No. 397, aground on Penfield Reef, 29 November 1945. (Sikorsky Historical Archive)
Sikorsky R-5 medevac, Korean War
U.S. Air Force H-5 (Sikorsky S-51) lifts off during the Korean War. (U.S. Air Force)
U.S. Coast Guard HOS-1 (Sikorsky S-49), with Igor Sikorsky as a passenger, over the Kill Devil Hills, North Carolina, 17 December 1947—the 44th annivesary of teh Wright Brothers first controlled, powered airplane flight. (Sikorsky Historical Archives)
U.S. Coast Guard HOS-1 (Sikorsky S-49), with Igor Sikorsky as a passenger, over the Kill Devil Hills, North Carolina, 17 December 1947—the 44th annivesary of the Wright Brothers first controlled, powered airplane flight. (Sikorsky Historical Archives)
U.S. Army YH-18A 49-2889 (Sikorsky S-52-2) (Ed Coates Collection)
U.S. Army YH-18A 49-2889 (Sikorsky S-52-2) (Ed Coates Collection)
SH-19A Air Rescue Sqd. AR.1999.026
U.S. Air Force SH-19A Chickasaw 51-3850 (Sikorsky S-55), Air Rescue Service. (U.S. Air Force)
Sikorsky H-34A-SI Choctaw (S-58) 57-1743 hovers in ground effect. Later registered as a civilian aircraft, N47246). (U.S. Army)
U.S. Army H-34A-SI Choctaw (Sikorsky S-58) 57-1743 hovers in ground effect. Later registered as a civilian aircraft, N47246). (U.S. Army)
Sikorsky CH-37 Mojave heavy-lift helicopter
U.S. Marine Corps CH-37 Mojave (Sikorsky S-56) heavy-lift helicopter
A U.S. Navy Sikorsky SH-3A Sea King (S-61), Bu. No. 149867, near Oahu, Hawaiian Islands, 5 April 1976. (PH2 (AC) Westhusing, U.S. Navy)
U.S. Navy SH-3A Sea King (Sikorsky S-61), Bu. No. 149867, near Oahu, Hawaiian Islands, 5 April 1976. (PH2 (AC) Westhusing, U.S. Navy)
A Sikorsky HH-3E Jolly Green Giant (66-13290) ot the 37th ARRS, hovering in ground effect at Da Nang, 1968. (U.S. Air Force)
U.S. Air Force HH-3E Jolly Green Giant (Sikorsky S-61R), 66-13290, of the 37th ARRS, hovering in ground effect at Da Nang, 1968. (U.S. Air Force)
Sikorsky CH-54A Tarhe 68-18448, Nevada National Guard, 16 Nober 1989. (Mike Freer/Wikipedia)
U.S. Army CH-54A Tarhe 68-18448 (Sikorsky S-64) heavy-lift helicopter, Nevada National Guard, 16 November 1989. (Mike Freer/Wikipedia)
Sikorsky MH-53M Pave Low IV, 68-8424, prepares for its last combat mission, Iraq, 27 September 2008. (A1C Jason Epley, U.S. Air Force)
U.S. Air Force MH-53M Pave Low IV 68-8424 (Sikorsky S-65), prepares for its last combat mission, Iraq, 27 September 2008. (A1C Jason Epley, U.S. Air Force)
U.S. Army Special Forces soldiers dismount a Sikorsky UH-60 Blackhawk, Zabul Province, Afghanistan, 21 January 2010. (Staff Sergeany Aubree Clute, U.S. Army)
U.S. Army Special Forces soldiers dismount a Sikorsky UH-60 Blackhawk, Zabul Province, Afghanistan, 21 January 2010. (Staff Sergeant Aubree Clute, U.S. Army)
U.S. Army UH-60L Blackhawk (Sikorsky S-70), Iraq, 2004. (Staff Sergeant Suzanne M. Jenkins, U.S. Air Force)
U.S. Army UH-60L Blackhawk (Sikorsky S-70), Iraq, 2004. (Staff Sergeant Suzanne M. Jenkins, U.S. Air Force)
Sikorsky HH-60G Pave Hawk 89-26212. (U.S. Air Force)
U.S. Air Force HH-60G Pave Hawk (Sikorsky S-70) 89-26212, Kunar Province, Afghanistan. (Captain Erick Saks, U.S. Air Force)
British Airways' Sikorsky S-61N G-BEON, 1982. ( )
British Airways’ Sikorsky S-61N G-BEON, 1982.
An Erickson Air-Crane, Inc. Sikorsky S-64 Skycrane drops water on a forest fire. (Sikorsky Archives)
An Erickson Air-Crane, Inc., Sikorsky S-64 Skycrane drops water on a forest fire. (Sikorsky Archives)
1280px-040327-pb-firehawk-17-16
A Los Angeles County Fire Department Sikorsky S-70A Firehawk, N160LA, during a rescue near Palmdale, California, 27 March 2004. (Alan Radecki/Wikipedia)
A Queen's Helicopter Flight Sikorsky S-76C, s/n 760753, G-XXEB (Russell Lee/Wikipedia)
A Queen’s Helicopter Flight Sikorsky S-76C, s/n 760753, G-XXEB (Russell Lee/Wikipedia)
Cougar Helicopters' Sikorsky S-92A C-GKKN landing at Ilulissat Airport, Greenland, 5 August 2010. (Algkalv/Wikipedia)
Cougar Helicopters’ Sikorsky S-92A C-GKKN landing at Ilulissat Airport, Greenland, 5 August 2010. (Algkalv/Wikipedia)
Sikorsky CH-53K King Stallion (Sikorsky, A Lockheed Martin Company)
The prototype Sikorsky CH-53K King Stallion (Sikorsky, A Lockheed Martin Company)

© 2017, Bryan R. Swopes

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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 angle 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 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 September 2013, two remained in service.

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

© 2015, Bryan R. Swopes

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