Tag Archives: Sikorsky S-61 Sea King

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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6 March 1965

The crew of the record-setting Sikorsky SH-3A Sea King, Dawdling Dromedary, aboard USS Franklin D. Roosevelt (CVA-42), 6 March 1965. Left to right, ADJ1 Paul J. Bert, Lieutenant David A. Biel, Commander James R. Williford. (U.S. Navy)
The crew of the record-setting Sikorsky SH-3A Sea King, Dawdling Dromedary, aboard USS Franklin D. Roosevelt (CVA-42), 6 March 1965. Left to right, ADJ1 Paul J. Bert, Lieutenant David A. Biel, Commander James R. Williford. (U.S. Navy)

6 March 1965: A U.S. Navy/Sikorsky SH-3A Sea King helicopter named Dawdling Dromedary, piloted by Commander James R. Williford and Lieutenant David A. Beil, with Aviation Machinist Mate 1st Class Paul J. Bert, took off from the aircraft carrier USS Hornet (CVS-12), alongside NAS North Island, San Diego California, at 4:18 a.m., Pacific Standard Time, (12:18 UTC) and flew non-stop, without refueling, to land aboard another aircraft carrier, USS Franklin D. Roosevelt (CVA-42), off Mayport, Florida, at 11:10 p.m. Eastern Standard Time (04:10 UTC). The distance flown was 3,388.70 kilometers (2,105.64 miles) with an elapsed time of 16 hours, 52 minutes, and set a Fédération Aéronautique Internationale (FAI) World Record for Distance Without Landing.¹ This exceeded the previous record distance by more than 750 miles (1,207 kilometers).²

On takeoff, Dawdling Dromedary had a gross weight of 23,000 pounds (10,433 kilograms), about 4,000 pounds (1,814 kilograms over its normal operating weight. Its fuel load was 1,690 gallons (6,397 liters) and it had only 60 gallons (227 liters) remaining on landing.

After clearing Guadalupe Pass between Carlsbad, New Mexico, and El Paso, Texas, (5,414 feet, 1650 meters) the crew shut down one the the SH-3A’s two turboshaft engines in an effort to reduce fuel consumption. They flew on a single engine for 9½ hours, restarting the second engine as they descended through 5,000 feet (1,524 meters) over Jacksonville, Florida.

The flight crew of the Sikorsky SH-3A Sea King, Dawdling Dromedary, Bu. No. 14xxxx. (FAI)
The flight crew of the Sikorsky SH-3A Sea King, Dawdling Dromedary, Bu. No. 14xxxx. Left to right, ADJ1 Paul J. Bert, CDR James R. Williford and LT David A. Beil. (FAI)

Commander Williford, head of the Rotary Wing Branch, Flight Test Division, at the Naval Air Test Center, NAS Patuxent River, Maryland, was quoted in Naval Aviation News for the May 1965 issue:

“Since weight counted, the heater had been removed. We therefore wore rubber boots, long underwear, etc., but still were thoroughly chilled upon arrival. The temperature at 15,000 feet [4,572 meters] was -11° [-23.9 °C.] that night.

“The C-131 chase aircraft crew was amazed at our accuracy of navigation with a lone omni. Actually, it was such a clear day it was the old type of piloting, that is, ‘just north of that reservoir’ or ‘one mile south of that city,’ etc. We flew through mountain passes until Guadalupe, thence great circle route to Mayport.

“For the trip, +10 knots [18.5 kilometers per hour] tailwind average was needed, and it appeared we weren’t going to make it for the first 8–9 hours because we were behind in our time vs. distance plot. But as we climbed higher—climbing being limited by retreating blade stall—we gained stronger and more favorable winds. By the time we reached Valdosta, Georgia, we had about 35 knots [64.8 kilometers per hour] pushing us. That was a nice feature because the Okefenokee Swamp at night is no place for an autorotation with empty fuel tanks.”

—Commander James R. Williford, United States Navy, Naval Aviation News, May 1965, NavWeps No. 00-75R-3, at Pages 8–9.

Dawdling Dromedary is the same Sikorsky SH-3A that set a Fédération Aéronautique Internationale (FAI) world speed record for helicopters of 339 kilometers per hour (210.6 miles per hour), 5 February 1962, flown by Lieutenant Robert W. Crafton, USN, and Captain Louis K. Keck, USMC.³

The Sikorsky SH-3A Sea King was the first of the S-61 series of military and civil helicopters, designated as HSS-2 until 1962. It is a large twin-engine helicopter with a single main rotor/tail rotor configuration. The fuselage is designed to allow landing on water. The XHSS-2 made its first flight 11 March 1959. The helicopter was originally used as an anti-submarine helicopter.

The SH-3A is 72 feet, 7 inches (22.123 meters) long and 16 feet, 10 inches (5.131 meters) high with all rotors turning. The main rotors and tail can be folded for more compact storage aboard aircraft carriers, shortening the aircraft to 46 feet, 6 inches (14.173 meters). 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 (3.150 meters). They each have a chord of 7–11/32 inches (0.187 meters). At 100% NR, the main rotor turns 203 r.p.m. and the tail rotor, 1,244 r.p.m.

The SH-3A was powered by two General Electric T58-GE-6 turboshaft engines, which had a Normal Power rating of 900 horsepower, and Military Power rating of 1,050 horsepower. The main transmission was rated for 2,300 horsepower, maximum. (Later models were built with more powerful T58-GE-8 engines. Early aircraft were retrofitted.)

The SH-3A has a cruise speed of 125 knots (144 kilometers per hour) at Sea Level, and a maximum speed of 135 knots (155 kilometers per hour) at Sea Level. The service ceiling is 14,000 feet (4,267 meters). The design maximum gross weight is 16,237 pounds (7,365 kilograms). The SH-3A had a combat endurance of 4 hours.

In 1962, the HSS-2 was redesignated SH-3A Sea King. Many early production aircraft have remained in service and have been 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.

Sikorsky produced the last S-61 helicopter in 1980, having built 794. Production has been licensed to manufacturers in England, Italy, Canada and Japan. They have produced an additional 679 Sea Kings.

Sikorsky SH-3A Sea King, Bu. No. 14xxxx, the Dawdling Dromedary. (FAI)
Sikorsky SH-3A Sea King, Bu. No. 14xxxx, the Dawdling Dromedary. (FAI)

¹ FAI Record File Number 2179

² FAI Record File Number 2180: 2,170.70 kilometers (1,348.81 miles), set by Captain Michael N. Antoniou, U.S. Army, flying a Bell YUH-1D Iroquois, 60-6029, from Edwards Air Force Base, California, to Rogers, Arkansas, 27 September 1964.

³ FAI Record File Number 13121. (See TDiA, 5 February 1962.)

© 2017, Bryan R. Swopes

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