Tag Archives: Boeing KC-135A Stratotanker

17 January 1966

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Boeing KC-135A-BN Stratotanker 58-0004 refuels Boeing B-52G-75-BW Stratofortress 57-6741. These are the same type aircraft that were involved in the 1966 Palomares Incident. (Boeing)

17 January 1966: A United States Air Force Boeing B-52G-115-BW Stratofortress, 58-0256, and its 7-man crew, along with a second B-52, were flying an Airborne Nuclear Alert patrol over the Mediterranean Sea. The bomber, call sign “Tea 16,” was armed with four Mark 28 nuclear bombs carried in its bomb bay.

At approximately 10:30 a.m., the two B-52s rendezvoused with two Boeing KC-135A-BN Stratotankers, based at Morón Air Base, Spain, for the second aerial refueling of the mission. The aircraft were at 31,000 feet (9,448 meters) off the southern coast of Spain.

Major Larry G. Messinger, a veteran of World War II, aboard as a relief pilot, was flying Tea 16 from the left seat. The aircraft commander, Captain Charles J. Wendorf, was in the right, co-pilot’s seat, while 1st Lieutenant Richard J. Rooney, the assigned co-pilot, rode in the Instructor Pilot’s seat.

Major Messinger later said, “We came in behind the tanker, and we were a little bit fast, and we started to overrun him a little bit. . . .”

A boom operator’s view as a B-52 Stratofortress refuels. (John E. Considine/NASM)

B-52G 58-0256 collided with the refueling boom of “Troubadour 14” (KC-135A 61-0273).¹ The boom penetrated the bomber’s fuselage, broke structural members and the left wing broke off. The B-52 exploded. The fully-loaded tanker, on fire, went into a steep dive. At 1,600 feet (488 meters), it also exploded.

The four crewmen aboard the tanker were killed. Three of the seven men on the B-52 ejected, and the co-pilot, who was not in an ejection seat, literally fell out of the disintegrating bomber. The navigator’s parachute did not open and he was killed. Three others were unable to escape the doomed airplane and were also killed.

Wreckage of B-52G 58-0256 at Palomares, Spain, January 1966. (Kit Talbot/The New York Times)

As the B-52 broke apart, the four nuclear bombs it carried in the bomb bay fell free. Three of them fell near the fishing village of Palomares. In two of these, the conventional explosives that “implode” the plutonium to start a chain reaction, detonated on impact, but a nuclear explosion did not occur. However, plutonium was scattered over the area. The third bomb was recovered intact, though it was slightly damaged. The retarding parachute of the fourth Mark 28 opened and it was carried offshore by the wind and fell into the Mediterranean Sea.

The missing B28 is recovered. (Department of Energy)

A massive recovery operation took place. The fourth bomb was recovered after five months. It had come to rest in an underwater canyon at a depth of 2,550 feet (777 meters).

1,400 tons of soil was packed into more than 6,000 steel drums and taken to the United States.
1,400 tons of soil was packed into more than 6,000 steel drums and taken to the United States.

558 acres (226 hectares) of land in and around Palomares was contaminated. The soil was removed and placed in steel barrels for transportation to the United States for burial at the Savannah River Plant, a nuclear reservation in South Carolina.

Three airmen position a B28Y1 1.1 megaton thermonuclear bomb for loading aboard a B-52 Stratofortress. (U.S. Air Force)
Three airmen position a B28Y1 thermonuclear bomb for loading aboard a B-52 Stratofortress. (TSgt. Boyd Belcher, U.S. Air Force)

The Mark 28 was a two-stage radiation-implosion thermonuclear bomb which was designed by the Los Alamos National Laboratory and produced from January 1958 to May 1966. In 1968, it was redesignated B28. More than 4,500 were manufactured in as many as 20 variants. Explosive yield varied between 70 kilotons and 1.45 megatons. The B28Y1 in the photograph above is a 1.1 megaton weapon. The bomb remained in service until 1991.

¹ Author Barbara Moran writes:

     What happened next is disputed. Wendorf says he still had his eye on the tanker when he heard an explosion coming from the back of the B-52.  The plane pitched down and to the left. Fire and debris shot into the cockpit and the plane began to come apart.

     The other pilots agree that the accident began with an explosion in the back of the B-52. But the official accident report tells a different story. Investigators concluded that the B-52 overran the KC-135 and then pitched upward and rammed the tanker. The collision ripped the tanker’s belly open, spilling jet fuel through the plane, onto the bomber, and into the air. A fireball quickly engulfed both planes.

     Rooney and Wendorf suspect that fatigue failure—a problem in the B-52—caused a portion of the tail to break off. Flying debris sparked an explosion in one of the gas tanks, and the plane came apart. After the initial explosion, the bomber may have rammed the tanker—everything happened so quickly that the pilots can’t be sure. But they insist that the explosion came first and that it came from the back of the bomber.

     We may never know conclusively whether a collision triggered the accident. After a crash, it is Air Force custom to bury the wreckage. Because the accident occurred on foreign soil, SAC dumped the debris into the ocean. The one surviving member of the investigation board has refused to speak publicly about the accident.

—The Day We Lost the H-Bomb, by Barbara Moran, Presidio Press, 2009, Chapter 2, Pages 30–31

© 2025, Bryan R. Swopes

30 December 1964

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A Boeing KC-135A Stratotanker refuels a Boeing B-52E Stratofortress. (U.S. Air Force)

30 December 1964: The United States Air Force accepted the last of 732 Boeing KC-135 Stratotankers: KC-135A serial number 64-14840. The new tanker was assigned to the 380th Air Refueling Squadron at Plattsburgh Air Force Base, New York, 12 January 1965.

According to the most recent Air Force Fact Sheet, 414 KC-135R and -135RT tankers are still in service with the United States Air Force: 167 active duty Air Force, 67 Air Force Reserve, and 180 Air National Guard. It is estimated that the fleet is 33% through their design lifetime limits. (There are also 25 special variants of the C-135, such as the OC-135B Open Skies, RC-135S Cobra Ball, RC-135U Combat Sent, RC-135V Rivet Joint, and RC-135W Rivet Joint.)

Boeing RC-135V Rivet Joint, 62-4139. (U.S. Air Force)

Built as an aerial refueling tanker to support the U.S. Air Force fleet of B-52 Stratofortress strategic bombers, an initial order for 24 tankers was soon increased to 250. Eventually 732 KC-135As were built by Boeing, and an additional 81 of other versions.

With the company internal designation of Model 717, the KC-135 was developed from the Model 367-80 proof-of-concept prototype, the “Dash Eighty.” The Stratotanker is very similar in appearance to the Model 707 and 720 airliners but is structurally a different aircraft. It is also shorter than the 707 and has a smaller diameter fuselage.

Boeing KC-135R Stratotankers of the 40th Air Expeditionary Group, forward deployed to support B-52 operations. (SMSGT John Rohrer, U.S. Air Force)
Boeing KC-135R Stratotankers of the 40th Air Expeditionary Group, forward deployed to support B-52 operations. (SMSGT John Rohrer, U.S. Air Force)

The Stratotanker was originally operated by a flight crew of four: pilot, co-pilot, navigator and refueling boom operator. Upgrades over the decades have simplified operation and the crew has been reduced to two pilots and the boom operator.

The KC-135R is 136 feet, 3 inches (41.529 meters) long (156 feet/47.549 meters with fueling boom extended), with a wingspan of 130 feet, 10 inches (39.878 meters), and overall height of 41 feet, 8 inches (12.700 meters). Its maximum takeoff weight is 322,500 pounds (146,284 kilograms).

The Stratotanker can carry up to 200,000 pounds (90,718 kilograms) of fuel for inflight refueling. It can also be configured to carry 83,000 pounds (37,648 kilograms) of cargo, or 80 passengers.

Boeing KC-135R Stratotanker 64-14840 at Rickenbacker Air National Guard Base, Columbus, Ohio, 2018. (Ohio Air National Guard)

The KC-135A was originally powered by four Pratt & Whitney J57-P-59W turbojet engines producing 13,750 pounds of thrust (61.163 kilonewtons) for takeoff, using water injection. The fleet has been re-engined with more efficient CFM International CFM56-2B1 (F108-CF-100) engines. Modified airplanes are designated KC-135R. The CFM56-2 is a two-spool, axial-flow, high-bypass turbofan with a single fan stage, 12-stage compressor section (3 low pressure and 9 high pressure stages), annular combustor, and a 5-stage turbine (1 high pressure and 4 low pressure stages). The engine is rated at 21,634 pounds of thrust (96.233 kilonewtons).

The tanker has a maximum speed of 350 knots (402 miles per hour/648 kilometers per hour) below 26,500 feet (8,077 meters), and 0.90 Mach when above that altitude. It has a range of 1,500 miles (2,424 kilometers) when carrying 150,000 pounds (68,039 kilograms) of transfer fuel. The service ceiling is 50,000 feet (15,200 meters).

The newest Stratotanker in service with the United States Air Force, KC-135R 64-14840 is 59 years old. It is presently assigned to the 121st Air Refueling Wing, Ohio Air National Guard.

The final Boeing Stratotanker, KC-135R 64-14840, remains in service with the 121st Air Refueling Wing, Ohio Air National Guard, based at Rickenbacker Air National Guard Base, Columbus Ohio. (Ohio Air National Guard)

© 2018, Bryan R. Swopes

5 September 1983

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Captain Robert J. Goodman's Boeing KC-135A Stratotanker refuels and tows a crippled McDonnell Douglas F-4E Phantom II over the North Atlantic. (U.S. Air Force)
Captain Robert J. Goodman’s Boeing KC-135A Stratotanker refuels and tows a crippled McDonnell Douglas F-4E Phantom II over the North Atlantic. (U.S. Air Force)

5 September 1983: A Strategic Air Command Boeing KC-135A Stratotanker of the 42nd Air Refueling Squadron, Loring  AFB, Maine, was sent to rendezvous with a flight of McDonnell Douglas F-4E Phantom II fighter bombers crossing the Atlantic Ocean enroute to Europe. As they began to refuel the fighters, one F-4E began to lose power in one of its engines, and also lost part of its hydraulic system. The Phantom’s pilot had difficulty maintaining speed and altitude as he tried to hook up with the tanker, and the second engine began to overheat. The two aircraft flew at just above the Stratotanker’s landing speed so that the Phantom could keep up, but as it slowed further, the Phantom’s angle of attack had to increase to maintain lift. This exceeded the mechanical limits of the refueling boom and the two airplanes separated without the fighter having received a full fuel load.

LCOL Robert J. Goodman, USAF (1943–2011). (U.S. Air Force)
LCOL Robert J. Goodman, USAF (1943–2011). (U.S. Air Force)

The crew of the F-4E was in serious danger. It was unlikely that the airplane could remain in the air for much longer. It was decided to head for Gander, Newfoundland, the closest place to land, 500 miles (806 kilometers) away. Captain Robert J. Goodman, U.S. Air Force, aircraft commander of the Stratotanker, decided to escort the crippled fighter which continued to lose altitude. It was necessary to try to refuel it three more times, and on occasion, the tanker actually towed the fighter back to altitude.

With the help of the tanker, the Phantom II finally arrived at Gander and landed safely.

For their efforts to save the lives of the crew of the F-4E, Captain Goodman and his crew, Captain Michael F. Clover, 1st Lieutenant Karol F. Wojcikowski and Staff Sergeant Douglas D. Simmons, Crew E113, were awarded the Mackay Trophy “For outstanding achievement while on a routine refueling mission involving F-4E aircraft, saving a valuable aircraft from destruction and its crew from possible death.”

SAC Crew E113, left to right: 1st Lieutenant Karol F. Wocjikowski, Captain Michael F. Clover, Captain Robert J. Goodman and Staff Sergeant Douglas D. Simmons. (U.S. Air Force)

The Mackay Trophy which is awarded annually for “the most meritorious flight of the year by an Air Force person, persons, or organization.” It is kept at the Smithsonian Institution, National Air and Space Museum.

The Mackay Trophy.
The Mackay Trophy.

© 2015, Bryan R. Swopes

31 August 1956

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Dix Loesch climbs aboard City of Renton while Tex Johnston waits. (Boeing)

31 August 1956: The first production Boeing KC-135A Stratotanker, 55-3118, named City of Renton, made its first flight with company test pilots Alvin Melvin (“Tex”) Johnston and Richards Llewellyn (“Dix”) Loesch, Jr., on the flight deck.

City of Renton, the first Boeing KC-135A Stratotanker, 55-3118, takes off for the first time. (Seattle Post Intelligencer)

Built as an aerial refueling tanker to support the U.S. Air Force fleet of B-52 strategic bombers, an initial order for 29 tankers was soon followed by three additional orders, bringing the total to 275 airplanes by the end of Fiscal Year 1958.¹ Eventually 732 KC-135As were built by Boeing, and an additional 81 of other versions.

KC-135 City of Renton. (Seattle Post-Intelligencer)
Boeing KC-135A Stratotanker 55-3118, City of Renton, just prior to touchdown. (Seattle Post-Intelligencer)

With the company internal designation of Model 717, the KC-135 was developed from the Model 367-80 proof-of-concept prototype, the “Dash Eighty.” The Stratotanker is very similar in appearance to the Model 707 and 720 airliners but is structurally a different aircraft. It is also shorter than the 707 and has a smaller diameter fuselage.

Boeing Aircraft Co. President Bill Allen talks to test pilots Tex Johnston and Dix Loesch after first flight of the Model-367-80 prototype. (Seattle Post-Intelligencer)
Boeing Aircraft Co. President Bill Allen talks to test pilots Tex Johnston and Dix Loesch after first flight of the Model 367-80, prototype of the KC-135A Stratotanker. (Seattle Post-Intelligencer)

The Stratotanker was originally operated by a flight crew of four: pilot, co-pilot, navigator, and refueling boom operator. Upgrades over the decades have simplified operation and the crew has been reduced to two pilots and the boom operator. The tanker’s maximum transfer fuel load is 200,000 pounds (90,719 kilograms). The KC-135 can carry 83,000 pounds (37,648 kilograms) of cargo, and up to 37 passengers.It can also be configured to carry cargo or up to 32 passengers.

The KC-135A is 136 feet, 3 inches (41.529 meters) long, with a wingspan of 130 feet, 10 inches (39.878 meters) and overall height of 41 feet, 8 inches (12.700 meters). The Stratotanker’s maximum takeoff weight is 322,500 pounds (146,284 kilograms).

The KC-135A was powered by four Pratt & Whitney J57-P-59W turbojet engines. The J57 was a two-spool, axial-flow engine with a 16-stage compressor section (9 low- and 7-high-pressure stages) and a 3-stage turbine section (1 high- and 2 low-pressure stages). These engines were rated at 13,750 pounds of thrust (61.16 kilonewtons), each. The J57-P-59W was 183.5 inches (4.661 meters) long, 38.9 inches (0.988 meters) long and weighed 4,320 pounds (1,920 kilograms).

The Stratotanker fleet has been re-engined with more efficient CFM International CFM56 turbofan engines which produce 21,634 pounds of thrust (96.23 kilonewtons), each. The upgraded aircraft are designated KC-135R.

Boeing KC-135A Stratotanker 55-3118, City of Renton, escorted by the “Dash 80.” (Flight Global)

The tanker has a cruise speed of 530 miles per hour (853 kilometers per hour) at 30,000 feet (9,144 meters). The service ceiling was 50,000 feet (15,240 meters). Its range is 1,500 miles (2,414 kilometers) when carrying 150,000 pounds (68,039 kilograms) of transfer fuel, and the maximum ferry range is 11,015 miles (17,727 kilometers).

Of the 803 KC-135 aircraft built, 396 remain in service with the U.S. Air Force (as of 14 May 2018). It is estimated that the fleet is 33% through their design lifetime limits.

The first production airplane, 55-3118, was used for flight testing. It was later modified into an EC-135K Head Dancer airborne command post. Today, the first Stratotanker is on display at the front gate of McConnell Air Force Base, Kansas.

Boeing KC-135A-BN Stratotanker 55-3118, City of Renton, refuels B-52C-50-BO Stratofortress 54-2676. (U.S. Air Force)

¹ KC-135A-BN: 57-1418–57-1514; 57-2589–57-2609; 58-0001–58-0130; total: 275

© 2018, Bryan R. Swopes

6 August 1955

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Looking out across the right wing of the Boeing 367–80, inverted, at the city of Seattle, 6 August 1955. (Bill Whitehead/Boeing)

6 August 1955: Boeing’s Chief of Flight Test, Alvin M. “Tex” Johnston, barrel-rolled the Model 367-80, prototype of the KC-135 Stratotanker and 707, over Lake Washington.

Twice.

This photograph was taken by the flight test engineer, Bill Whitehead.

Boeing had risked $16,000,000 in a private venture to build the Dash 80 in order to demonstrate its capabilities to potential civilian and military customers, while rivals Douglas and Lockheed were marketing their own un-built jet airliners. Put into production as the U.S. Air Force KC-135 Stratotanker air refueling tanker and C-135 Stratolifter transport, a civil variant was also produced as the Boeing 707, the first successful jet airliner. Though they look very similar, the 707 is structurally different than the KC-135 and has a wider fuselage.

Boeing Model 367-80 (“Dash Eighty”) in flight. (Joe Parke/Wikipedia)

The prototype Boeing Model 367-80 was operated by a pilot, co-pilot and flight engineer. The airplane’s wing was mounted low on the fuselage and the engine nacelles were mounted on pylons under the wing, as they were on Boeing’s B-47 Stratojet and B-52 Stratofortress. The wings and tail surfaces were swept to 35°. The Dash 80 was 127 feet 10 inches (38.964 meters) long with a wingspan of 129 feet, 8 inches (39.522 meters) and overall height of 38 feet (11.582 meters). Its empty weight was 92,100 pounds (41,775.9 kilograms) and loaded weight was 190,000 pounds (86,182.6 kilograms).

In tanker configuration, the Boeing 367-80 refuels a Boeing B-52 Stratofortress. The chase plane is a Lockheed T-33A Shooting Star. (U.S. Air Force)

N70700 was powered by four Pratt & Whitney Turbo Wasp JT3C engines. This engine is a civil variant of the military J57 series. It is a two-spool, axial-flow turbojet engine with a 16-stage compressor and 2-stage turbine. The JT3C-6 (used in the first production 707s) was rated at 11,200 pounds of thrust (49.82 kilonewtons), and 13,500 pounds (60.05 kilonewtons) with water/methanol injection). The JT3C is 11 feet, 6.6 inches (3.520 meters) long, 3 feet, 2.9 inches (0.988 meters) in diameter, and weighs 4,235 pounds (1,921 kilograms).

These gave the 367-80 a cruise speed of 550 miles per hour (885 kilometers per hour) and a maximum speed of 0.84 Mach (582 miles per hour, 937 kilometers per hour) at 25,000 feet (7,620 meters). The service ceiling was 43,000 feet (13,106 meters). Its range was 3,530 miles (5,681 kilometers).

The Boeing 707 has a wider fuselage and is structurally different than teh KC-135. (Boeing)

Boeing continued to use the 367–80 for testing, finally retiring it 22 January 1970. At that time, its logbook showed 2,346 hours, 46 minutes of flight time (TTAF). It was flown to Davis-Monthan Air Force Base, Tucson, Arizona, and placed in storage. In 1990, Boeing returned it to flyable condition and flew it back it to Renton where a total restoration was completed. Many of those who had worked on the Dash 80, including Tex Johnston, were aboard.

The pioneering airplane was presented to the Smithsonian Institution and is on display at the National Air and Space Museum, Steven V. Udvar-Hazy Center. The Boeing 367-80 was designated an International Historic Mechanical Engineering Landmark by the American Society of Mechanical Engineers.

820 of the C-135 series and 1,010 Model 707 aircraft were built from 1957–1979.

(The Boeing Model 367-80 is on display at the Steven F. Udvar-Hazy center, Smithsonian Institution National Air and Space Museum. (Photo by Dane Penland, National Air and Space Museum, Smithsonian Institution)

© 2024, Bryan R. Swopes