Tag Archives: Aircraft Accident

12 January 1937

Wreck of Western Air Express Boeing 247D NC13315, Los Pinetos Peak, near newhal, California, 12 January 1937. (Santa Clarita Valley History in Pictures)
Wreck of Western Air Express Flight 7, a Boeing Model 247D, NC13315, at Los Pinetos Peak near Newhall, California, 12 January 1937. (Santa Clarita Valley History in Pictures)

12 January 1937: Western Air Express Flight 7, a Boeing 247D airliner, NC13315, had originated at Salt Lake City, Utah, and after a stop at Las Vegas, Nevada, continued on toward Union Air Terminal, Burbank, California. Aboard were a crew of three and ten passengers.

In fog and falling snow, Captain William Walker Lewis and co-pilot Clifford P. Owens crossed over Saugus, California,

“. . . at 5,200 feet [1,585 meters], aircraft was already 300 feet [91 meters] too low. . . Pilot tried to contact Burbank without any success. Due to low visibility caused by fog, pilot did not realize he was flying at an insufficient altitude. In a descent rate of 525 feet per minute [2.667 meters per second], aircraft hit Pinetos Peak.”

— Bureau of Air Commerce report.

According to statements after the accident, Captain Lewis suddenly saw a ridge immediately ahead, and unable to avoid it, cut his engines and raised the nose in an attempt to reduce the impact. The accident occurred at 11:07 a.m., Pacific Time.

Illustration from the Los Angeles Times, Vol. LVI, Wednesday, 13 January 1937, Page 6, Columns 3–6.

The crash was heard by patients at the Olive View Sanitorium and ranchers on the north side of the mountains. Two hours later, passenger Arthur S. Robinson arrived at the hospital and said, “Get help up there for the twelve others. It was a forced landing—they’re all injured but I believe they’re all alive.”

Boeing 247D NC13315, 12 January 1937. (Santa Clarita Valley History in Pictures)
Boeing 247D NC13315, 12 January 1937. (Santa Clarita Valley History in Pictures)

One passenger, James A. Braden, president of the Braden-Sutphin Ink Co., of Cleveland, Ohio, was killed immediately. The co-pilot, Owens, and three more of the passengers died of injuries within the next several days.

One of those who died was famed adventurer and film maker Martin Johnson. His wife, Osa Johnson, was also aboard Flight 7 and was seriously injured. Another survivor, Robert T. Anderson, would later own Pea Soup Anderson, a famous restaurant in Buellton, California.

Osa and Martin Johnson. (Osa and Martin Johnson Safari Museum)
Osa and Martin Johnson. (Osa and Martin Johnson Safari Museum)

The Boeing Model 247 is considered to be the first modern airliner because of its all-metal, semi-monocoque construction, cantilevered wing and retractable landing gear. It was 50 miles per hour (80 kilometers per hour) faster than its contemporaries, and could climb on one engine with a full load.

The Model 247 was operated by a pilot, co-pilot and a flight attendant and carried up to ten passengers. The airplane was 51 feet, 5 inches (15.672 meters) long, with a wingspan of 74 feet, 1 inch (22.581 meters) and overall height of 12 feet, 5 inches (3.785 meters). The empty weight was 8,921 pounds (4,046.5 kilograms) with a maximum takeoff weight of 16,805 pounds (7,622.6 kilograms).

The Duralamin skin panels were anodized, rather than painted, for corrosion protection. This saved weight, and resulted in the 247’s characteristic gray-green color.

Western Air Express Boeing 247D NC13315. The nose baggage compartment door is open. (Ed Coates Collection)
Western Air Express Boeing 247D NC13315. The nose baggage compartment door is open. (Ed Coates Collection)

The airliner was powered by two air-cooled, supercharged, 1,343.804-cubic-inch-displacement (22.021 liters) Pratt & Whitney Wasp S1H1-G nine-cylinder radial engines with a compression ratio of 6.03:1. The S1H1-G had a Normal Power rating of 550 horsepower at 2,200 r.p.m., to 8,000 feet (2,438 meters), and 600 horsepower at 2,250 r.p.m. for Takeoff. They drove three-bladed Hamilton Standard constant-speed propellers through a 3:2 gear reduction, when installed on the 247D. The Wasp S1H1-G was 3 feet, 11.80 inches (1.214 meters) long, 4 feet, 3.61 inches (1.311 meters) in diameter, and weighed 930 pounds (422 kilograms).

The Boeing 247 had a maximum speed of 200 miles per hour (322 kilometers per hour) with a cruising speed of 188 miles per hour (303 kilometers per hour. It had a range of 745 miles (1,199 kilometers) and a service ceiling of 25,400 feet (7,742 meters).

75 Model 247s were built. 60 were operated by Boeing Air Transport.

[Note: the windshield was canted forward to prevent instrument panel lighting from reflecting into the cockpit at night. Unfortunately, ground lighting was reflected instead. This was soon changed to a rearward slant and resulted in a slight increase in speed.]

Western Air Express Boeing 247D NC13315, 1933. (SCVhistory.com)
Western Air Express Boeing 247D NC13315, 1933. (Santa Clarita Valley History in Pictures)

© 2019, Bryan R. Swopes

11 January 1938

A Pan American Airways Sikorsky S-42.
A Pan American Airways Sikorsky S-42.

11 January 1938: Pan American Airways’ Sikorsky S-42B NC16734, Samoan Clipper, took off from Pago Pago, American Samoa, enroute Auckland, New Zealand. The airplane had a crew of seven, commanded by Captain Edwin C. Musick, the airline’s senior pilot, and a cargo of mail.

About two hours out, the number four engine began leaking oil. Captain Musick ordered the engine shut down. The flight radioed that they were returning to Pago Pago. They never arrived. Wreckage, a large oil slick, various documents and articles of the crew’s clothing were found by the U.S. Navy seaplane tender USS Avocet (AVP-4), 14 miles (22.5 kilometers) west of the island. It was apparent that the S-42 had exploded in mid-air.

The cause of the explosion is not known with certainty but based on Captain Musick’s handling of a similar problem with one of  Samoan Clipper‘s  engines on an earlier flight, a possible cause can be suggested.

Pan American Airways’ Samoan Clipper. (Hawaii Aviation)

On the earlier flight, the number four engine had begun seriously overheating and Musick ordered the flight engineer to shut it down. Because of the decreased power with only three engines, Captain Musick ordered the crew to begin dumping fuel to decrease the weight of the airplane before landing.

Pan American had tested the fuel dumping characteristics of the Sikorsky S-42 using dye, and had learned that because of the air flow patterns around the wings, the fluid tended to accumulate around the trailing edge of the wings and that it could actually be sucked into the wings themselves.

As fuel was being dumped on the previous flight, fuel vapors were present in the cabin, requiring all electrical systems to be shut off—even though it was night. Liquid gasoline was also dripping into the cockpit from the wing above.

Pan American Airways’ Sikorsky S-42B NC16734 at Pago Pago, 24 December 1937. (Unattributed)

Samoan Clipper had been very heavy with fuel when it departed for the long transoceanic flight to Auckland. Presuming that Captain Musick once again ordered fuel to be dumped prior to landing back at Pago Pago, and that the vapors collected around the wings, the fuel could have been detonated by the electrical motors which were used to lower the flaps for flight at slower speed, or by coming into contact with the hot exhaust of the engines.

Two independent investigations were carried out by Pan American and by the United States Navy, and both came to this conclusion.

Captain Edwin Charles Musick, Chief Pilot, Pan American Airways. (1894–1938)

There were no survivors of the explosion. Killed along with Captain Musick were Captain Cecil G. Sellers, Second Officer P.S. Brunk, Navigator F.J. MacLean, Flight Engineer J.W. Stickrod, Flight Mechanic J.A. Brooks and Radio Operator T.D. Findley.

The Sikorsky S-42B was a four-engine long-range flying boat built for Pan American Airways by the Vought-Sikorsky Aircraft Division of United Technologies at Stratford, Connecticut. It was 68 feet (20.726 meters) long with a wingspan of 118 feet, 2 inches (36.017 meters). The S-42 had an empty weight of 19,764 pounds ( kilograms) and gross weight of 38,000 pounds ( kilograms). It could carry up to 37 passengers.

The S-42B was powered by four air-cooled, supercharged, 1,690.537-cubic-inch-displacement (27.703 liters) Pratt & Whitney Hornet S1E-G nine-cylinder radial engines with a compression ratio of 6.5:1. The S1E-G had a Normal Power rating of 750 horsepower at 2,250 r.p.m., to 7,000 feet (2,134 meters), and 875 horsepower at 2,300 r.p.m., for Takeoff. The engines drove three-bladed Hamilton Standard constant-speed propellers through a 3:2 gear reduction. The S1E-G was 4 feet, 1.38 inches (1.254 meters) long, 4 feet, 6.44 inches (1.383 meters) in diameter, and weighed 1,064 pounds (483 kilograms).

The S-42B has a cruise speed 165 miles per hour (266 kilometers per hour) and maximum speed of 188 miles per hour (303 kilometers per hour) at 5,000 feet (1,524 meters). The service ceiling was 16,000 feet (4,877 meters), and it could maintain 7,500 feet (2,286 meters) with three engines. Its range was 1,930 miles (3,106 kilometers).

Boris Vasilievich Sergievsky. (Test & Research Pilots, Flight Test Engineers)

During flight testing of the S-42, Sikorsky test pilot Boris Vasilievich Sergievsky, with co-pilot Raymond B. Quick, set three Fédération Aéronautique Internationale world records for payload and altitude.¹  Later, Captain Musick, with Sergievsky and world-famous aviator Charles A. Lindbergh, flew the S-42 to set eight Fédération Aéronautique Internationale world records for speed.²

Ten Sikorsky S-42, S-42A and S-42B flying boats were built for Pan Am. None remain in existence.

Pan American Airways' Sikorsky S-42B NC16734, Samoan Clipper, moored at mechanic's Bay, Auckland, New Zealand, December 1937. The flying boat in the background is a Short S.23 Empire, G-ADUT, named Centaurus. (Turnbull Library)
Pan American Airways’ Sikorsky S-42B NC16734, Samoan Clipper, moored at Mechanic’s Bay, Auckland, New Zealand, December 1937. The flying boat in the background is a Short S.23 Empire, G-ADUT, named Centaurus. (Turnbull Library)

¹ 26 April 1934 FAI Record File Numbers: 11583: Greatest load to 2,000 meters (6,562 feet): 7,533 kilograms (16,652 pounds).  17 May 1934: 11582 and 11978: Altitude with a 5,000 Kilogram (11,023 pounds) Load, 6,220 meters (20,407 feet).

² 1 April 1934 FAI Record File Numbers: 11517: Speed over a closed circuit of 1,000 Kilometers (621.3 statute miles), 253,60 km/h (157.58 m.p.h.); 11518:  . . .  with a 500 Kilogram (1,102 pounds) Payload, 253,60 km/h (157.58 m.p.h.); 11519:  . . . with a 1,000 Kilogram (2,205 pounds) Payload, 253,60 km/h (157.58 m.p.h.);  11520: . . . with a 2,000 kilogram (4,409 pounds) Payload, 253,60 km/h (157.58 m.p.h.); 11521: Speed over a closed circuit of 2,000 Kilometers (1,242.7 statute miles), 253,18 km/h (157.32 m.p.h); 11522:  . . . with a 500 Kilogram Payload, 253,18 km/h (157.32 m.p.h.); 11523:  . . . with a 1,000 Kilogram Payload, 253,18 km/h (157.32 m.p.h.); 11524: . . . with a 2,000 Kilogram Payload, 253,18 km/h (157.32 m.p.h.).

© 2019, Bryan R. Swopes

10 January 1964

Boeing B-52H-170-BW 61-023
Boeing B-52H-135-BW Stratofortress 60-0006, similar in appearance to to 61-023. (U.S. Air Force)

10 January 1964: This Boeing B-52H Stratofortress, serial number 61-023, flown by Boeing test pilot Charles F. (“Chuck”) Fisher, was conducting structural testing in turbulence near East Spanish Peak, Colorado. The other crew members were pilots Richard V. Curry and Leo Coer, and navigator James Pittman. Dick Curry was flying the airplane and Chuck Fisher, the aircraft commander, was in the co-pilot’s position. Pittman was on the lower deck.

The bomber was carrying two North American Aviation GAM-77 Hound Dog cruise missiles on pylons under its wings.

The Boeing B-52 Stratofortress had been designed as a very high altitude penetration bomber, but changes in Soviet defensive systems led the Strategic Air Command to change to very low altitude flight as a means of evading radar. This was subjecting the airframes to unexpected stresses. “Ten-Twenty-Three” (its serial number was 61-023, shortened on the vertical fin to “1023”) had been returned to Boeing Wichita by the Air Force to be instrumented to investigate the effects of high-speed, low-altitude flight on the 245-ton bomber.

Flying at 14,300 feet (4,359 meters) and 345 knots (397 miles per hour, 639 kilometers per hour), indicated air speed, the airplane encountered severe clear air turbulence and lost the vertical stabilizer. Several B-52s had been lost under similar circumstances. (Another, a B-52D, was lost just three days later at Savage Mountain, Maryland.)

East Spanish Peak (left), 12,688 feet (3,867 meters) and West Spanish Peak, 13,626 feet (4,153 meters), Sangre de Cristo Mountains, Colorado. (Footwarrior)
East Spanish Peak (left), 12,688 feet (3,867 meters) and West Spanish Peak, 13,626 feet (4,153 meters), Sangre de Cristo Mountains, Colorado. (Footwarrior)
Charles F. Fisher. (Argenta Images)
Charles F. Fisher. (Argenta Images)

Chuck Fisher immediately took control of the B-52. He later reported,

“As the encounter progressed, a very sharp-edged blow which was followed by many more. We developed an almost instantaneous rate of roll at fairly high rate. The roll was to the far left and the nose was swinging up and to the right at a rapid rate. During the second portion of the encounter, the airplane motions actually seemed to be negating my control inputs. I had the rudder to the firewall, the column in my lap, and full wheel, and I wasn’t having any luck righting the airplane. In the short period after the turbulence I gave the order to prepare to abandon the airplane because I didn’t think we were going to keep it together.”

A Boeing report on the incident, based on installed sensors and instrumentation aboard -023, said that the bomber had

“. . . flown through an area containing the combined effects of a (wind) rotor associated with a mountain wave and lateral shear due to airflow around a mountain peak. . . Gust initially built up from the right to a maximum of about 45 feet per second [13.7 meters per second](TAS), then reversed to a maximum of 36 feet per second [11 meters per second] from the left, before swinging to a maximum of about 147 feet per second [44.8 meters per second] from the left followed by a return to 31 feet per second [9.5 meters per second].”

Fisher flew the bomber back to Wichita and was met by a F-100 Super Sabre chase plane. When the extent of the damage was seen, the B-52 was diverted due to the gusty winds in Kansas. Six hours after the damage occurred, Chuck Fisher safely landed the airplane at Eaker Air Force Base, Blythville, Arkansas. He said it was, “the finest airplane I’ve ever flown.”

Boeing B-52H-170-BW Stratofortress 61-023, "Ten-Twenty-Three", after losing the vertical fin, 10 January 1964. (Boeing)
Boeing B-52H-170-BW Stratofortress 61-023, “Ten-Twenty-Three”, after losing the vertical fin, 10 January 1964. (Boeing)

61-023 was repaired and returned to service. It remained active with the United States Air Force until it was placed in storage at Tinker Air Force Base, Oklahoma, 24 July 2008.

Charles F. Fisher and the Boeing test crew with B-52H Stratofortress 61-023. (Boeing)
Charles F. Fisher at left,  and the Boeing test crew with B-52H Stratofortress 61-023. (Boeing)

The B-52H is a sub-sonic, swept wing, long-range strategic bomber. It has a crew of five. The airplane is 159 feet, 4 inches (48.6 meters) long, with a wing span of 185 feet (56.4 meters). It is 40 feet, 8 inches (12.4 meters) high to the top of the vertical fin. Maximum Takeoff Weight (MTOW) is 488,000 pounds (221,353 kilograms).

There are eight Pratt & Whitney TF33-PW-3 turbofan engines mounted in two-engine pods suspended under the wings on four pylons. Each engine produces a maximum of 17,000 pounds of thrust (75.620 kilonewtons). The TF-33 is a two-spool axial-flow turbofan engine with 2 fan stages, 14-stage compressor stages (7 stage intermediate pressure, 7 stage high-pressure) and and 4-stage turbine (1 stage high-pressure, 3-stage low-pressure). The engine is 11 feet, 10 inches (3.607 meters) long, 4 feet, 5.0 inches (1.346 meters) in diameter and weighs 3,900 pounds (15,377 kilograms).

The B-52H can carry approximately 70,000 pounds (31,750 kilograms) of ordnance, including free-fall bombs, precision-guided bombs, thermonuclear bombs and cruise missiles, naval mines and anti-ship missiles.

The bomber’s cruise speed is 520 miles per hour (837 kilometers per hour) and its maximum speed is 650 miles per hour (1,046 kilometers per hour) at 23,800 feet (7,254 meters) at a combat weight of 306,350 pounds. Its service ceiling is 47,700 feet (14,539 meters) at the same combat weight. The unrefueled range is 8,000 miles (12,875 kilometers).

With inflight refueling, the Stratofortress’s range is limited only by the endurance of its five-man crew.

The B-52H is the only version still in service. 102 were built and as of June 2019, 76 are still in service. Beginning in 2013, the Air Force began a fleet-wide technological upgrade for the B-52H, including a digital avionics and communications system, as well as an internal weapons bay upgrade. The bomber is expected to remain in service until 2040.

Boeing B-52H-170-BW Stratofortress 61-023 taxiing at Minot Air Force Base, North Dakota. (Senior Airman Cassandra Jones, U.S. Air Force)
Boeing B-52H-170-BW Stratofortress 61-023 taxiing at Minot Air Force Base, North Dakota. (Senior Airman Cassandra Jones, U.S. Air Force)

© 2016, Bryan R. Swopes

10 January 1956

Lieutenant Barty R. Brooks, USAFR, standing on the wing of a North American Aviation F-86F Sabre, Korea, 1954. (U.S. Air Force)

10 January 1956: First Lieutenant Barty Ray Brooks, United States Air Force Reserve, a pilot assigned to the 1708th Ferrying Wing, Detachment 12, at Kelly Air Force Base, Texas, along with two other pilots from the same unit, Captain Rusty Wilson and Lieutenant Crawford Shockley, picked up three brand new F-100C Super Sabre fighters at the North American Aviation Inc. assembly plant at Air Force Plant 42, Palmdale, California. It was to be a short flight, as these three jets were being taken to nearby George Air Force Base, Adelanto, California, only 42.5 miles (68.4 kilometers) to the east. Brooks was flying F-100C-20-NA, serial number 54-1907.

This North American Aviation F-100C-25-NA Super Sabre, serial number 54-2099, is similar to the fighter flown by Lieutenant Brooks, 10 January 1956. (U.S. Air Force)
This North American Aviation F-100C-25-NA Super Sabre, serial number 54-2099, is similar to the fighter flown by Lieutenant Brooks, 10 January 1956. (U.S. Air Force)
This photograph shows the lower section of the nose gear strut of an F-100 Super Sabre. The scissors ling is the hinged assembly. A red pin is visible at teh center hinge. Thi spin had been removed by ground handlers to tow the fighter, but had not been reinstalled before Lt. Brooks' flight.
This photograph shows the lower section of the nose gear strut of an F-100 Super Sabre. The scissors link is the hinged assembly. A red pin is visible at the center hinge. This pin had been removed by ground handlers to tow the fighter, but had not been secured with a safety pin when it was reinstalled before Lt. Brooks’ flight. (Michael Benolkin)

The brief flight was uneventful until the pilots lowered the landing gear to land at George AFB. One of the other pilots saw that the scissors link joining the upper and lower sections of the nose gear strut on Brooks’ Super Sabre was loose. Concerned that he would not be able to steer the fighter after touching down, Brooks diverted to Edward Air Force Base, 36 miles (57 kilometers) to the northwest, where a larger runway and more emergency equipment was available. Captain Wilson escorted Lieutenant Brooks to Edwards.

The F-100C Super Sabre had no flaps and required a high speed landing approach. Lieutenant Brooks had only 674 total flight hours as a pilot, and just 39 hours in the F-100.

During his final approach to the runway Brooks allowed the fighter to slow too much and the outer portion of the wings stalled and lost lift. This shifted the wings’ center of lift forward, which caused the airplane to pitch up, causing even more of the outer wing to stall.

Lieutenant Brooks fought to regain control of the airplane, but he was unable to. At 4:27 p.m., Pacific Standard Time, the F-100 crashed on the runway and exploded. Barty Ray Brooks was killed.

Edwards Air Force Base is the center of flight testing for the U.S. Air Force. In preparation for a test later that afternoon, the base film crews had their equipment set up along the runway and captured the last seconds of Brook’s flight on film. This is the most widely seen crash footage, and is still in use in pilot training. It is named “The Sabre Dance.”

Still image from cine film of Barty Brooks’ F-100C Super Sabre just before it crashed at Edwards Air Force Base, 10 January 1956. (U.S. Air Force)

Barty Ray Brooks was born in Martha Township,  Oklahoma, 2 December 1929. He was the third child of Benjamin Barto Brooks, a farmer, and Maye Henry Brooks. The family later moved to Lewisville, Texas. Brooks graduated from Lewisville High School in 1948, then studied agriculture at Texas A&M University, College Station, Texas.

Barty Ray Brooks, 1950. (Aggieland ’50)

While at Texas A&M, Brooks was a member of the Reserve Officers Training Corps (R.O.T.C.). On graduation, 30 May 1952, Brooks was commissioned as a second lieutenant, United States Air Force Reserve.

Lieutenant Brooks was trained as a pilot at Columbus Air Force Base, Mississippi, and Laredo Air Force Base, Texas. In 1954, he was assigned to the 311th Fighter Bomber Squadron, 58th Fighter Bomber Group, Taegu Air Base (K-2), Republic of South Korea. Brooks flew the Republic F-84 Thunderjet and North American Aviation F-86 Sabre. When he returned to the United States he was assigned to the 1708th Ferrying Wing.

The remains of 1st Lieutenant Barty Ray Brooks were interred at the Round Grove Cemetery, Lewisville, Texas.

The article, “The Deadly Sabre Dance,” by Alan Cockrell is highly recommended:

http://www.historynet.com/deadly-sabre-dance.htm

© 2018, Bryan R. Swopes

10 January 1954

The first production de Havilland DH.106 Comet 1, G-ALYP, in formation with the two prototypes, G-ALVG and G-ALZK. G-ALYP also broke up in flight, 10 January 1954. (Ed Coates Collection)
The first production de Havilland DH.106 Comet 1, G-ALYP, in formation with the two prototypes, G-ALVG and G-ALZK. (Ed Coates Collection)

10 January 1954: British Overseas Airways Corporation Flight 781 departed Ciampino Airport, Rome, Italy, at 0931 UTC, enroute to Heathrow Airport, London, England. The airliner was the first production de Havilland DH.106 Comet I, G-AYLP, serial number 06003. The flight crew were Captain Alan Gibson, First Officer William John Bury, Engineer Officer Frances Charles McDonald and Radio Officer Luke Patrick McMahon. There were two flight attendants, Frank L. Saunders and Jean Evelyn Clark, and 29 passengers. After departure began climbing toward its cruise altitude of 27,000 feet (8,230 meters).

At 0951 UTC, 20 minutes after takeoff, Captain Gibson was conversing by radio with another BOAC flight. It is presumed that Flight 781 had reached its cruise altitude. Captain Gibson was heard to say, “George How Jig from George Yoke Peter [the phonetic alphabet call signs for Argonaut G-ALHJ and Comet G-AYLP] did you get my—” and the transmission suddenly ended. Nothing more was heard from Flight 781 and it did not arrive at its destination.

Several fishermen had seen the airliner crash into the Mediterranean Sea near the island of Elba and recovered bodies of the victims, which were found to have suffered the effects of explosive decompression.

Wreckage of Comet G-AYLP was found on the sea floor, 12 February 1954, and it was apparent that the airliner had broken up in flight. Consideration was given to the possibility of a bomb having been placed aboard, or that an uncontained turbojet engine failure had penetrated the pressure cabin resulting in a structural failure of the fuselage through explosive decompression.

De Havilland Comet 1 G-AYLP (Crash-aerien)
De Havilland Comet 1 G-AYLP (www.crash-aerien.news)

After two prototypes, G-AYLP was the first production Comet. It was the fourth DH.106 to be lost in just over fourteen months. With the cause of Flight 781’s crash undetermined, B.O.A.C. grounded its remaining Comet airliners. De Havilland engineers recommended more than 60 modifications to improve perceived weaknesses in the Comet fleet.

Extensive testing by the Royal Aircraft Establishment determined that the Comet’s pressurized fuselage could be expected to fail from metal fatigue after 1,000 pressurization/depressurization cycles. G-AYLP had experienced 1,290 pressurization cycles during the 3,681 hours it had flown since its first flight, 9 January 1951.

The Royal Aircraft Establishment placed DH.106 Comet I G-AYLU in a water tank to conduct pressurization tests. (lessonslearned.faa.gov)
The Royal Aircraft Establishment placed DH.106 Comet I G-AYLU in a water tank to conduct pressurization tests. (lessonslearned.faa.gov)

Reconstruction of G-ALYP’s fuselage revealed that a fatigue crack had begun at a rivet hole of a square opening for the airplane’s automatic direction finder antenna. With the differential in pressure from inside and outside the passenger cabin, this crack had spread along the top of the fuselage through a passenger window and back to to the elevators at the tail. The fuselage structure then failed explosively and the airplane’s tail section came off. The wings then failed and fuel carried inside caught fire. The cockpit section tore away from the remaining fuselage section.

Illustration showing fatigue fractures in the fuselage skin of G-AYLP.

In reporting the Probable Cause of the destruction of G-AYLP, the committee wrote,

We have formed the opinion that the accident at Elba was caused by structural failure of the pressure cabin, brought about by fatigue. We reach this opinion for the following reasons:

(i) The low fatigue resistance of the cabin has been demonstrated by the test described in Part 3, and the result is interpretable as meaning that there was, at the age of the Elba aeroplane, a definite risk of fatigue failure occurring.

(ii) The cabin was the first part of the aeroplane to fail in the Elba accident.

(iii) The wreckage indicates that the failure in the cabin was the same basic type as that produced in the fatigue test.

(iv) This explanation seems to us to be consistent with all the circumstantial evidence.

(v) The only other defects found in the aeroplane were not concerned at Elba, as demonstrated by the wreckage.

Report of the Public Inquiry into the causes and circumstances of the accident which occurred on the 10th January 1954, to the Comet aircraft G-AYLP.

Four months later, April 8 1954, a Comet 1 operated by South African Airways as Flight 201 from Rome to Cairo, G-ALYY, crashed near Naples, Italy with the deaths of all 21 persons aboard. The airplane had explosively broken up at an altitude of 35,000 feet (10,668 meters).

The de Havilland DH.106 Comet fleet was grounded and the Ministry of Transportation withdrew the type’s Certificate of Airworthiness. Production of the airliner at Hatfield came to a stop.

BOAC's DH.106 Comet I G-ALYW in long term storage at Heathrow, 12 September 1954. (RuthAS via Wikipedia)
BOAC’s DH.106 Comet I G-ALYW in long term storage at Heathrow, 12 September 1954. (RuthAS via Wikipedia)

De Havilland redesigned the Comet, and as the Comet 4 it had a successful career in airline operation. It eventually lost out to the faster, longer range Boeing 707 and Douglas DC-8. Production ceased in 1964 and B.O.A.C. retired its last Comet in 1965.

The Comet was again redesigned as the Hawker Siddeley Nimrod maritime reconnaissance aircraft.

© 2016, Bryan R. Swopes