20 July 1969, 20:17:39 UTC, T + 102:45:39.9

Apollo 11 LM -5, Eagle, just after separation from the Command/Service Module in Lunar Orbit, 20 July 1969. (Michael Collins/NASA)

102:45:25 Aldrin: Four forward. Four forward. Drifting to the right a little. Twenty feet, down a half.

102:45:31 Duke: Thirty seconds (until the ‘Bingo’ call).

102:45:32 Aldrin: Drifting forward just a little bit; that’s good.

(Pause)

102:45:40 Aldrin: Contact Light.

102:45:43 Armstrong: Shutdown.

102:45:44 Aldrin: Okay. Engine Stop.

102:45:45 Aldrin: ACA out of Detent.

102:45:46 Armstrong: Out of Detent. Auto.

102:45:47 Aldrin: Mode Control, both Auto. Descent Engine Command Override, Off. Engine Arm, Off. Four-thirteen is in.

102:45:57 Duke: We copy you down, Eagle.

102:45:58 Armstrong: Engine arm is off. (Pause) Houston, Tranquility Base here. The Eagle has landed.

The shadow of the LM Eagle cast on the lunar surface at Mare Tranquillitatis, 20 July 1969. The hills are raised portions of the rim of a 200 meter crater and are about 200 meters from the LM. (Edwin Eugene Aldrin, Jr./NASA)

© 2018, Bryan R. Swopes

20 July 1969, 18:12:01 UTC, T + 100:40:01.9

The Apollo 11 Lunar Module Eagle shortly after separation from teh Command and Service Module, in orbit around the Moon, 20 July 1969. (NASA)
The Apollo 11 Lunar Module Eagle, with Neil Armstrong and Buzz Aldrin aboard, shortly after separation from the Command and Service Module, in orbit around the Moon, 20 July 1969. (Michael Collins, NASA)

20 July 1969, 18:12:01 UTC, T + 100 hours, 40 minutes, 1.9 seconds: The Lunar Module Eagle completes the separation maneuver, moving away from the Apollo 11 Command and Service Module Columbia.

© 2015, Bryan R. Swopes

20 July 1955

Convair NB-36 Nuclear Test Aircraft
Convair NB-36H Nuclear Test Aircraft. (U.S. Air Force)

20 July 1955: At Carswell Air Force Base, Fort Worth, Texas, the Convair NB-36H Nuclear Test Aircraft, serial number 51-5712, made its first flight.

In the late 1940s engineers began working on an aircraft that could be powered by a nuclear reactor. The reactor would heat air to provide jet thrust, rather than burning fuel and air to do so. A 60 megawatt reactor was envisioned.

The NB-36 was built to test the shielding requirements of an airborne nuclear reactor and to determine the effects of radiation on aircraft systems.

Convair NB-36H 51-5712. (U.S. Air Force 230502-F-ZS999-1002)

The Nuclear Test Aircraft was built from a Convair B-36H-20-CF Peacemaker strategic bomber, one of 61 that had been destroyed or damaged by a tornado that struck Carswell AFB in 1952. 51-5712 was so heavily damaged that the airframe was written off, but it was rebuilt with a completely new nose section with a shielded cockpit, and was otherwise very heavily modified by Convair. Originally designated XB-36H-20-CF, this was changed to NB-36H in June 1956.

The shielded cockpit unit of the NB-36H (U.S. Air Force)
The shielded cockpit unit of the NB-36H. This assembly weighed 11 tons. (U.S. Air Force)

A one-megawatt Aircraft Shield Test Reactor developed by the Oak Ridge National Laboratory, weighing approximately 35,000 pounds (15,875 kilograms), was installed in the bomber’s aft bomb bay. Though the reactor was fully operational, it did not power the airplane.

As with other B-36s, a combination of six Pratt & Whitney Wasp Major R-4360-53 air-cooled, 28-cylinder radial engines, and four General Electric J47-GE-19 turbojet engines, powered the NB-36.

The Convair NB-36H, 51-5712, with a Boeing B-50 Superfortress. (U.S. Department of Defense DF-SC-83-09332)

The modified bomber could reach a maximum speed of 420 miles per hours at 47,000 feet. It had a maximum gross weight of 357,500 pounds.

During the test program, the NB-36 made 47 flights with a total of 215 hours flight time.

Based on the test results, the entire project was cancelled, and 51-5712 was scrapped at Fort Worth in 1958.

Convair NB-36H Nuclear Test Aircraft 51-5712. (Convair)
Convair NB-36H Nuclear Test Aircraft 51-5712, 6 August 1956. (Convair)

© 2016, Bryan R. Swopes

20 July 1933

Wiley Post's Lockheed Model 5C Vega, NR105W, Winnie Mae, after a landing accident at Flat, Alaska. (Unattributed)
Wiley Post’s Lockheed Model 5C Vega, NR105W, Winnie Mae, after a landing accident at Flat, Alaska. Standing in front of the Winnie Mae, at left, wearing a hat and overalls, and with a pipe in his right hand, is John Beaton. Beaton was a miner whose discovery of gold at Flat began the Iditarod Gold Rush. Post is not seen in this image. (Unattributed)

20 July 1933: At 11:58 a.m. (17:58 UTC) on the fifth day of his solo around-the-world flight, Wiley Post took off from Khabarovsk, Siberia, heading toward Nome, Alaska, 2,416 miles (3,888 kilometers) to the east-northeast (great circle route).

A very tired Wiley Post photographed at Flat, Alaska, after Winnie Mae has been repaired. (University of Alaska image identifier UAF-1998-129-3)
A very tired Wiley Post photographed at Flat, Alaska, after Winnie Mae has been repaired. (University of Alaska Fairbanks)

Post missed his destination and, exhausted, became lost. He flew over Alaska for approximately seven hours before sighting a remote U.S. Army Signal Corps radio station at Flat, Alaska, a small gold mining town located along the Iditarod Trail in southwestern Alaska.

Post landed his Lockheed Model 5C Vega, NR105W, The Winnie Mae of Oklahoma, on a small landing field at the eastern edge of the town. The airplane’s wheels sank into the soft surface and Winnie Mae nosed over, damaging its propeller, engine cowling and right landing gear strut. Wiley Post was unhurt.

The International News Service (INS) reported:

. . . Utter exhaustion which numbed his mind so that he could not properly pilot his course caused him to become lost for seven hours over Alaska yesterday after he had been in the air more than 22 hours on his 3,000-mile hop from Siberia to Alaska during which he battled the most adverse weather conditions, he revealed today.

Sighting the Flat radio station caused him to land here. He said that he could at least get his directions again. He ran into soft ground on the landing field, nosing over, breaking his right wheel strut, damaging the engine cowling and valves and bending the propeller. Post was uninjured. . . .

A replacement propeller was flown in from Fairbanks and repairs were made. He continued the following day, taking off at 7:28 a.m., local.

The “Winnie Mae,” Wiley Post’s Lockheed Model 5C Vega, NR105W, after nosing over at Flat, Alaska, 20 July 1933. (Unattributed)

© 2016, Bryan R. Swopes

19 July 1989

United Airlines’ DC-10 N1819U, Flight 232, on final approach to Sioux City Gateway Airport, 19 July 1989. In this image, damage to the right horizontal stabilizer is visible, and the aircraft tail cone is missing. (Wikipedia)

19 July 1989: United Airlines Flight 232 was a McDonnell Douglas DC-10-10, registration N1819U, enroute from Stapleton International Airport, Denver, Colorado to O’Hare International Airport, Chicago, Illinois. There were 296 persons aboard the airliner: 285 passengers and 11 crew members. The flight crew consisted of Captain Alfred C. Haynes, First Officer William Record, and Second Officer Dudley Dvorak. Also aboard, riding in the passenger cabin, was an off-duty United Airlines DC-10 Check Airman, Captain Dennis E. Fitch.

At 3:16:10 p.m., the fan disk of the airliner’s tail-mounted General Electric CF6-6 turbofan engine (Number Two) failed catastrophically. Shrapnel from the exploding engine chopped through the DC-10’s tail section and severed the three independent hydraulic systems that powered the flight control surfaces. The crew immediately lost their ability to control the airliner with rudder, elevators and ailerons. Flaps and wing leading edge slats were inoperative. Controls to the damaged engine also failed and only by cutting off fuel flow were they able to shut if down and prevention further damage or a fire. Landing gear could only be lowered by use of an emergency procedure.

The uncontrolled airliner immediately started to roll and dive. The pilots’ cockpit flight controls were completely useless to stop the roll. Only by varying the thrust on the two remaining wing mounted engines could some degree of control be maintained. Realizing there was a problem with the DC-10, Captain Fitch told a flight attendant to inform Captain Haynes that he was aboard and ask if he could assist. Haynes immediately asked Fitch to come forward, and once there to take over the throttle controls while the crew dealt with all the other problems that were occurring.

Flight 232 radar  track. (NTSB)

The simultaneous loss of all three hydraulic systems was considered to be “impossible” and there were no emergency procedures to deal with the problem. The crew did the best they could by varying power on the two remaining engines to turn the airplane and to descend. They were heading for an emergency landing at Sioux City Gateway Airport, Iowa (SUX).

United Airlines Flight 232 on final approach to Sioux Gateway Airport, 19 July 1989. (Gary Anderson/Sioux City Journal)

At 4:00:16 p.m., the DC-10 touched down on Runway 22 at an estimated at 215 knots (247.4 miles per hour, 398.2 kilometers per hour) and a rate of descent of 1,620 feet per minute (8.23 meters per second). At about 100 feet (30.5 meters) above the ground, the airliner’s nose began to pitch downward and the airliner started to roll to the right. Touchdown was at the runway threshold, just left of the centerline.

The DC-10 touched down at teh threshold of Runway 22, just left of the centerline.
The DC-10 touched down at the threshold of Runway 22, just left of the centerline.
Captain Alfred C. Haynes

The force of the impact caused the airframe break apart and the wreck rolled over to the right side of the runway. Fuel exploded and fire spread. 110 passengers and 1 flight attendant were killed in the crash and fire. There were 185 survivors of the crash, including the four pilots who were trapped in the crushed nose section of the airplane which had broken away from the main wreckage.

The National Transportation Safety Board (NTSB) investigation determined that the the center engine fan disk failed due to a crack which had formed when the original titanium ingot from which it was made had been cast 18 years before.

The official report said that a landing under these conditions was stated to be “a highly random event“. The NTSB further noted that “. . . under the circumstances the UAL flight crew performance was highly commendable and greatly exceeded reasonable expectations.”

This was one of the finest displays of airmanship during an inflight emergency since the beginning of aviation.

An iowa National Guard UH-1 medevac helicopter hovers over the wreckage of the United DC-10.
An Iowa National Guard UH-1 medevac helicopter hovers over the wreckage of the United Airlines DC-10, 19 July 1989.

© 2018, Bryan R. Swopes