Daily Archives: April 20, 2018

20 April 1978

Korean Air Lines’ Boeing 707-321B HL7429 on the frozen lake. (www.autoreview.ru)

20 April 1978: A Soviet Air Force Sukhoi Su-15TM interceptor attacked Korean Air Lines Flight 902, a Boeing 707 airliner which had overflown Soviet territory. A major navigational error by the flight crew caused Flight 902 to deviate approximately 150° to the right of its planned route from Paris, France, to Anchorage, Alaska.

Approximate flight path of Korean Air Lines Flight 902, 20 April 1978. (The Pan Am Historical Foundation/New York Times)

Captain Alexander Bosov, an interceptor pilot of the 365th IAP (Istrebitel’nyy Aviatsionnyy Polk, Fighter Aviation Regiment), Soviet Air Defense Forces, based at Afrikanda, Murmansk Oblast, Russia, had been sent to intercept the intruder. A second Su-15TM, piloted by Sergei Slobodchikov of the 265the IAP, was dispatched from Poduzmenie.

Bosov initially reported the airliner as the similar Boeing RC-135 military reconnaissance aircraft, but when he was closer, was able to recognize the markings of Korean Air Lines. He repeatedly informed his controllers that the airplane was a civilian airliner, describing its markings, but his superiors ordered him to shoot it down.

A Soviet Sukhoi Su-15 interceptor, 38 Red, armed with Kaliningrad R-98MR air-to-air missiles, 1 May 1989. (U.S. Department of Defense)

Captain Bosov fired two Vympel R-60 infrared-homing air-to-air missiles. One missed, but the second missile hit the 707’s left wing and detonated.

The airliner’s left wing, outboard of the Number 1 engine, was blown off. Shrapnel penetrated the passenger cabin, resulting in explosive decompression. Of the 109 persons on board, two were killed.

The descending wing section was picked up by Soviet air defense radar, with the return being interpreted as a cruise missile, and another interceptor was sent to attack it.

The flight crew, Captain Kim Chang Kyu Lee, First Officer Chyn Xing, and Navigator Lee Kun-shik, crash-landed the 707 on a frozen lake in the Karelian Autonomous Soviet Socialist Republic, near the USSR/Finland border.

After about two hours, Soviet soldiers arrived at the crash scene. The survivors were transported by helicopter to the town of Kem. On 22 April, they were flown to Murmansk, where a Pan American airliner took them out of the Soviet Union to Finland. Captain Kim and Navigator Lee remained under arrest in Leningrad for violating Soviet airspace. They were released 29 April 1978.

The cause of the navigational error has not been determined. Soviet authorities refused to cooperate in the investigation, and Cockpit Voice Recorder and Flight Data Recorder information has never been released publicly. Captain Kim later said that he believed that navigational equipment had malfunctioned. In public statements, the flight crew gave incomplete, inconsistent and contradictory information.

(Captain Kim had been a fighter pilot during the Korean War, flying the Mikoyan-Gurevich MiG-15 for the Korean People’s Air Force.)

Korean Air Lines’ Boeing 707-321B HL7429. (www.autoreview.ru)
Korean Air Lines’ Boeing 707-321B HL7429.
Korean Air Line’s Boeing 707-321B HL7429
Damage to teh fuselage of Boeing 707 (www.autoreview.ru)
Damage to the fuselage of Korean Air Lines’ Boeing 707-321B HL7429. (www.autoreview.ru)

Soviet news articles commended Captain Bosov for his skill in firing the missiles so that the airliner would only be damaged, rather than destroyed.

The damaged left wing of Flight 902
The damaged left wing of Korean Air Lines Flight 902. (www.autoreview.ru)

Flight 902 was a 1967 Boeing 707-321B, serial number 19363. It was first flown 9 September 1967, and was delivered to Pan American World Airways on 21 September 1967. The airliner was registered N428PA and named Clipper Star of Hope. The United States registration was cancelled 12 May 1977 when 19363 was exported to the Republic of Korea. It was reregistered HL7429.

Korean Air Lines’ Boeing 707-321B HL7429, photographed at Osaka International Airport, 1 August 1977. (항공사고/공대생의 일상블로그)

The Boeing 707-321B was 152 feet, 11 inches (46.609 meters) long, with a wingspan of 145 feet, 9 inches (44.425 meters) and overall height 42 feet, 1 inches (12.827 meters) at its operating empty weight. The leading edges of the wings and tail surfaces are swept 35°. The fuselage has a maximum diameter of 12 feet, 8.0 inches (3.759 meters). The -321B has a typical empty weight of 142,780 pounds (64,764 kilograms), and a maximum takeoff weight (MTOW) of 327,000 pounds (148,325 kilograms). The usable fuel capacity is 23,855 gallons (90,301 liters).

All 707-series aircraft are powered by four jet engines installed in nacelles below and forward of the wings on pylons. The -321B was equipped with the Pratt & Whitney Turbofan JT3D-3B engines. The JT3D is an axial-flow bypass turbojet engine. It has a 2-stage fan section, 13-stage compressor section (6 low- and 7 high-pressure stages), and a 4-stage turbine (1 high- and 3 low-pressure stages). The JT3D-3B has a Maximum Continuous Power rating of 16,400 pounds of thrust (72.95 kilonewtons) at Sea Level, and 18,000 pounds (80.07 kilonewtons) at Sea Level for Take Off. Its maximum r.p.m. limits are, N1, 6,850 r.p.m., and N2, 10,250 r.p.m.  The engine’s fan diameter is 4 feet, 5.1 inches (1.349 meters). It is 12 feet, 1.5 inches (3.696 meters) long and 4 feet, 5.0 inches (1.346 meters) in diameter. the -3B weighs 4,340 pounds (1,969 kilograms).

The Boeing 707-321B had a maximum operating speed (VMO) of 454 miles per hour (731 kilometers per hour) Indicated Air Speed (IAS) at 23,000 feet (7,010 meters). Above 23,000 feet, the VMO  was 0.887 Mach.

Boeing built 1,010 Model 707 airplanes between 1957 and 1979.

Сухой Су 15

The Сухой Су-15ТМ (Sukhoi Su-15, NATO designation, Flagon-E) is single-place, twin-engine, supersonic interceptor, designed and produced by the Sukhoi Design Bureau (OKB-51), near Moscow, Russia. The airplane’s configuration is described as a tailed delta. The prototype made its first flight 30 May 1962. The Su-15TM is the final production variant. It became operational in 1971 and was retired in 1993.

The Su-15TM was 22.03 meters (72 feet, 3.3 inches) long, with a wingspan of 9.34 meters (30 feet, 7.7 inches) and overall height of 4.843 meters (15 feet, 10.7). The compound delta wing is swept 55° at the 25% chord along the inner wing, decreasing to 45° for the outer wing. The wing area is 36.6 square meters (393.96 square feet). The interceptor has an empty weight of 10,874 kilograms (23,973 pounds) and a maximum takeoff weight (MTOW) of 17,900 kilograms (39,463 pounds).

Сухой Су 15

The Su-15TM was powered by two Tumansky R-13-300 engines. These are dual-spool axial-flow turbojets with afterburner. They use an 8-stage compressor section (3 low- and 5 high-pressure stages) and a 2-stage turbine (1 high- and 1 low-pressure stage). Each engine is rated at 40.2 kilonewtons (9,037 pounds of thrust), and 64.7 kilonewtons (14,545 pounds) with afterburner. The R-13-300 is 1.095 meters (3 feet, 7.1 inches) in diameter, 4.605 meters (15 feet, 1.3 inches) long, and weighs 1,205 kilograms (2,657 pounds).

Сухой Су 15

The Flagon-E had a cruise speed of 1,400 kilometers per hour (870 miles per hour), and a maximum speed of 2,230 kilometers per hour (1,386 miles per hour) at 12,000 meters (39,370 feet)—Mach 2.10. Its service ceiling was 18,500 meters (60,696 feet), and it had a maximum range of 1,700 kilometers (1,056 miles).

The Su-15TM was normally operated with a ground-controlled intercept system. The aircraft was flown with the autopilot engaged and it was controlled from the ground through a data link. When it was within weapons range, the pilot would take over to fire the missiles.

A Sukhoi Su-15TM, 21 Yellow, armed with R-60 and R98 air-to-air missiles.

The primary weapon for the Su-15 was the Vympel R-60 (NATO AA-8 Aphid) short-range infrared-homing air-to-air missile, or the Kaliningrad R-98 (NATO AA-3 Anab), which was available in either infrared-homing or radar-homing variants.

The R-60 was a Mach 2.7 missile with a 3 kilogram (6.6 pound) warhead. It is 2.090 meters (6 feet, 10.3 inches) long, 0.120 meters (0 feet, 4.72 inches) in diameter and weighs 43.5 kilograms (95.9 pounds). Its maximum fin span is 0.390 meters (1 foot, 3,4 inches). It had a maximum range of 8 kilometers (5 miles). This was the missile used against Korean Air Lines Flight 902.

Vympel R-60 infrared-homing air-to-air missile.

The R-98 was a Mach 2 missile carrying a 40 kilogram (88 pound) high explosive fragmentation warhead. Its maximum range was 23 kilometers (14 miles).

The Sukhoi Su-15 is the same type interceptor that shot down Korean Air Lines Flight 707. It is known as the “Boeing Killer” in recognition of its two victorious attacks on unsuspecting and unarmed commercial airliners.

Derelict HL7429 being dismantled during the summer of 1978. (colonel-baranez.livejournal.com)
Derelict HL7429 being dismantled during the summer of 1978. (colonel-baranez.livejournal.com)

© 2018, Bryan R. Swopes

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20 April 1962

E-334220 April 1962: “Neil’s Cross-Country.” NASA Research Test Pilot Neil Alden Armstrong conducts a flight to test the Minneapolis-Honeywell MH-96 flight control system installed in the third North American Aviation X-15, serial number 56-6672. The new system combined both aerodynamic and reaction thruster flight controls in one hand controller rather than the two used in X-15s -670 and -671, simplifying the tasks for the pilot.

On its fourth flight, -672 was air-dropped from the Boeing NB-52B Stratofortress drop ship, Balls 8, over Mud Lake, Nevada. Armstrong fired the Reaction Motors XLR99-RM-1 engine and let it burn for 82.4 seconds. The X-15 accelerated to Mach 5.31 (3,789 miles per hour/6,098 kilometers per hour). After the engine was shut down, the rocketplane continued to its peak altitude on a ballistic trajectory, reaching 207,500 feet (63,246 meters) before going over the top and beginning its descent back toward the atmosphere. The test of the new flight control system went well.

E63-9834Neil Armstrong began to pull out of the descent at about 100,000 feet (30,480 meters), but the X-15 “ricocheted” off the top of the atmosphere and climbed back to 115,000 feet (35,052 meters) where the aerodynamic control surfaces could not function. He used the reaction thrusters to turn toward the dry lake landing area at Edwards Air Force Base, but although the X-15 rolled into a left bank, it would not change direction and still in ballistic flight, went zooming by Edwards at Mach 3 and 100,000 feet in a 90° left bank.

As the X-15 dropped back into the atmosphere, Armstrong was finally able to get it slowed down, but he was far south of his planned landing site. By the time he got -672 turned around he was 45 miles (72.4 kilometers) to the south, over the Rose Bowl in Pasadena, and gliding through 45,000 feet (13,716 meters). There was real doubt that he would be able to make the X-15 stretch its glide to reach the dry lake.

E-7469In a masterful display of airmanship, Neil Armstrong was able to get the X-15 to reach the south end of the dry lake, 12 miles (19.3 kilometers) from the planned landing spot to the north. But it was a very close call. In debriefing, the pilots of the four F-104 chase planes were asked how much clearance Armstrong had as he crossed over the Joshua trees at the edge of the lake bed. One of them answered, “Oh, at least 100 feet—on either side.”

At 12 minutes, 28.7 seconds, this was the longest flight of the entire X-15 program. It is called “Neil’s cross-country flight.”

North American Aviation X-15 56-6670 with Neil A. Armstrong, Jr., NASA Research Test Pilot, Edwards AFB, 1960A U.S. Navy fighter pilot who flew 78 combat missions during the Korean War, Neil Armstrong became a civilian test pilot at NACA (National Advisory Committee on Aeronautics, the predecessor to NASA) in 1955. He made 7 flights in the X-15 before transferring to NASA’s Project Gemini in 1962.

Armstrong was command pilot for Gemini 8 and Gemini 11, commander of the backup flight crew of the Apollo 8 mission, and was commander of Apollo 11.

On 20 July 1969, Neil Alden Armstrong was the First Man To Stand on the Surface of The Moon.

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© 2018, Bryan R. Swopes

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20 April 1941

Squadron Leader Marmaduke Thomas St. John “Pat” Pattle, Officer Commanding No. 33 Squadron, Royal Air Force, and the Squadron Adjutant, Flight Lieutenant George Rumsey, standing by a Hawker Hurricane at Larissa, Thessaly, Greece, March–April 1941. (IWM)

20 April 1941: Squadron Leader Marmaduke Thomas St. John Pattle, D.F.C. and Bar, Royal Air Force, commanding No. 33 Squadron, was killed in action during the Battle of Athens when his Hawker Hurricane fighter was shot down by two or more Luftwaffe Messerschmitt Bf 110 fighters. Pattle’s airplane crashed into the sea near the Port of Piraeus, southwest of Athens.

Messerschmitt Bf 110 twin-engine heavy fighter, circa 1942. (Deutsches Bundesarchiv)

Squadron Leader Pattle may have been the highest-scoring Allied fighter ace of World War II. The exact number of enemy aircraft destroyed cannot be determined precisely because records were lost or destroyed during the Battle of Greece. The last officially acknowledged score was 23 airplanes shot down, mentioned in The London Gazette with the notice of the award of a Bar to his Distinguished Flying Cross. It is widely acknowledged that he shot down many more, and on at least two occasions, shot down five enemy airplanes in one day. Authors who have researched Pattle’s combat record believe that he shot down at least 50, and possibly as many as 60 aircraft.

For comparison, Air Vice Marshal James Edgar (“Johnnie”) Johnson, C.B., C.B.E., D.S.O. and Two Bars, D.F.C. and Bar, is officially credited by the Royal Air Force with shooting down 34 enemy airplanes. Colonel Francis Stanley (“Gabby”) Gabreski, United States Air Force, was credited with 28 kills during World War II. In the Pacific Theater of Operations, Major Richard Ira Bong is officially credited with 40 enemy airplanes shot down.

Marmaduke Thomas St. John Pattle was born at Butterworth, Cape Province, South Africa, 23 July 1914. He was the son of Sergeant-Major William John Pattle, British Army, and Edith Brailsford Pattle. After failing to be accepted by the South African Air Force, at the age of 21 years, he traveled to Britain to apply to the Royal Air Force. He was offered a short-service commission and sent to flight school.

Pattle was commissioned as an Acting Pilot Officer on probation, effective 24 August 1936. He trained as a fighter pilot in the Gloster Gauntlet, and was rated as exceptional. He was then assigned to No. 80 Squadron, which was equipped with the newer Gloster Gladiator. He was confirmed in the rank of Pilot Officer 29 June 1937.

Prototype Gloster Gladiator in flight, now marked K5200.

No. 80 Squadron was sent to Egypt to protect the Suez Canal. With the United Kingdom’s declaration of war on the Axis powers, Pattle and his unit were soon in combat with the Regia Aeronautica (the Italian Royal Air Force) across North Africa. He shot down his first enemy airplanes, a Breda Ba.65 and a Fiat CR.42, on 4 August 1940. Unfortunaely, Pattle was also shot down and he had to walk across the Libyan desert to friendly lines.

Distinguished Flying Cross

Pattle was promoted to Flight Lieutenant, 3 September 1940. He is credited with having shot down at least 15 Italian airplanes with the Gladiator.

In February 1941, No. 80 Squadron began flying the Hawker Hurricane. This was a huge technological advance over the Gladiator, and the Hurricane’s eight .303-caliber machine guns doubled the firepower of the biplane.  The squadron was sent to Greece, where it would engage the Luftwaffe.

Flight Lieutenant Pattle was awarded the Distinguished Flying Cross, 11 February 1941. The following month, 12 March 1941, Pat Pattle was promoted to Acting Squadron Leader, and given command of No. 33 Squadron at Larissa, Thessaly, Greece.

Squadron Leader Pattle was awarded a Bar to his DFC (a second award), 18 March 1941.

Pilots of No. 33 Squadron, Royal Air Force, with a Hawker Hurricane Mk.I fighter, V7419. Pattle is in the first row, seated, fifth from left. (Imperial War Museum)

Designed by Sydney Camm to meet a Royal Air Force Specification for a high speed monoplane interceptor, the airplane was designed around the Rolls-Royce PV-12 engine. The prototype Hawker Hurricane, K5083, first flew 6 November 1935.

The Hurricane was built in the traditional means of a light but strong framework covered by doped linen fabric. Rather than wood, however, the Hurricane’s framework used high strength steel tubing for the aft fuselage. A girder structure covered in sheet metal made up the forward fuselage. A primary consideration of the fighter’s designer was to provide good visibility for the pilot.

The Hawker Hurricane Mk.I was ordered into production in the summer of 1936. The first production airplane flew on 12 October 1937. The Hurricane Mk. I was 31 feet, 5 inches (9.576 meters) long with a wingspan of 40 feet, 0 inches (12.192 meters), and overall height of 10 feet, 6 inches (3.200 meters). Its empty weight was 5,234 pounds (2,374 kilograms) and maximum gross weight was 6,793 pounds (3,081 kilograms).

The Mk.I’s engine was a liquid-cooled, supercharged, 27.01 liter (1,648.96 cubic inches) Rolls-Royce R.M.1.S. Merlin Mk.III single-overhead-cam 60° V-12, rated at 990 horsepower at 2,600 r.p.m. at 12,250 feet (3,734 meters), and 1,030 horsepower at 3,000 r.p.m., at 10,250 feet (3,124 meters), using 87 octane aviation gasoline. The Merlin III drove the propeller through a 0.477:1 gear reduction ratio. It weighed 1,375 pounds (624 kilograms).

The fixed-pitch propeller was soon replaced with a three-bladed, two-pitch propeller, and then a three-bladed constant-speed propeller. Speed trials of a Mk.I equipped with a 10 foot, 9 inch (3.277 meters) diameter Rotol constant-speed propeller achieved a maximum True Air Speed in level flight of 316 miles per hour (509 kilometers per hour) at 17,500 feet (5,334 meters). The service ceiling was 32,250 feet (9,830 meters). The Mk.I’s range was 600 miles (966 kilometers) at 175 miles per hour (282 kilometers per hour).

The Hurricane Mk.I could climb to 20,000 feet in 9.7 minutes.

The fighter was armed with eight Browning .303 Mark II machine guns mounted in the wings, with 334 rounds of ammunition per gun.

Hawker Hurricane Mk.I at NACA Langley Memorial Aeronautical Laboratory. (NASA)

© 2018, Bryan R. Swopes

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