Aircraft type McDonnell Douglas DC-10-10
• Cargo door failure due to design flaw leading to rapid decompression
── June 12, 1972
── https://en.wikipedia.org/wiki/American_Airlines_Flight_96
── redesign of the rear-cargo door to open outward, in order to have more storage space in the cargo area ─ the door in passenger area of the aircraft has inward opening door; with inward opening door, when the aircraft is pressurized, it would be near impossible to open the door without depressurizing the aircraft.
── rear-cargo door would fail, causing rapid decompression, which would cause floor failure, resulting in severing the underfloor cables, compromising and destroying the ability to control the aircraft.
Aircraft type McDonnell Douglas DC-10-10
• Cargo door failure due to aircraft design flaw leading to explosive decompression, destruction of control systems, and loss of control
── 3 March 1974
── https://en.wikipedia.org/wiki/Turkish_Airlines_Flight_981
── March 3 – Turkish Airlines Flight 981, a McDonnell Douglas DC-10, crashes in the Ermenonville forest near Senlis, France, after the rear underfloor cargo door opens in mid-flight; all 346 on board die.
──
── The cargo door design flaws, and the consequences of a likely aircraft floor failure in the event of in-flight decompression on the DC-10, had been noted by Convair engineer Dan Applegate in a 1972 memo.[14] The memo was written after American Airlines Flight 96, being operated by another DC-10, experienced a rear cargo door failure similar to the one that occurred on Flight 981, also causing an explosive decompression. Fortunately, even though the pilots' ability to control Flight 96 was compromised by some severed underfloor cables in the damaged section of the plane, they were able to land in Detroit without further injuries – though Applegate warned that a more severe outcome was likely when (not if) a similar incident happened on another DC-10.
Aircraft type Boeing 747-100
• Cargo door failure resulting in an explosive decompression in mid-flight.
── February 24, 1989
── https://en.wikipedia.org/wiki/United_Airlines_Flight_811
── on February 24, 1989, United Airlines Flight 811, a 747-100, N4713U, which suffered an explosive decompression in mid-flight. killing 9 of 355.
── N4713U
──
── Based on the evidence available, and the attribution of prior cargo-door malfunctions to damage and ground crew mishandling, the NTSB operated from an assumption that a properly latched and locked 747 cargo door could not open in flight:[10]: 37
── N4713U: the NTSB learned that in N4713U's case, the aircraft had experienced intermittent malfunctions of its forward cargo door in the months prior to the accident.[10]: 51
── Focusing on damage to the door and maintenance procedures, the NTSB concluded that the accident was preventable human error, and not a problem inherent in the design or function of the aircraft's cargo door.
── Lee Campbell, a New Zealander returning home, was one of the fatalities on Flight 811. After his death, his parents Kevin and Susan Campbell investigated the cause using documents obtained from the NTSB.[12] The Campbells' investigation led them to conclude that the cause of the accident was not human error, but rather the combination of an electrical problem and an inadequate design of the aircraft's cargo door-latching mechanism. They later presented their theory to the safety board.[13]
── On September 26 and October 1, 1990, two halves of Flight 811's cargo door were recovered from the Pacific Ocean from 14,100 feet (4,300 m) below the ocean surface. The cargo door had fractured lengthwise across the center. ([ why would a cargo door fractured lengthwise across the center, why not a completely intacted cargo door broken off at the hinge (mobile attachment mechanism to the fuselage) ]) Recovery crews reported that no other debris or evidence of human remains had been discovered.[17] The NTSB inspected the cargo door and determined that the condition of the locking mechanism did not support its original conclusions. [1]: vi
── Additionally, in 1991, an incident occurred at New York's John F. Kennedy International Airport involving the malfunction of a United Airlines Boeing 747 cargo door.[18]
── https://www.ntsb.gov/doclib/recletters/1991/a91_83_84.pdf
──
https://web.archive.org/web/20121008002504/https://www.ntsb.gov/doclib/recletters/1991/A91_83_84.pdf
── [[ plot point for a movie: a circuit-breaker trip, an inadvertent operation of the electric door latch mechanism caused the ... door to open spontaneously despite being closed. ]]
── In the process of diagnosing the cause of a circuit-breaker trip, an inadvertent operation of the electric door latch mechanism caused the cargo door to open spontaneously despite being closed. An inspection of the door's electrical wiring discovered insulation breaches, and isolating certain electrical wires allowed the door to operate normally again.[1]: 66–68
── The lock sectors, latch cams, and latch pins on the door were inspected, and did not show any signs of damage of the type predicted by the NTSB's original hypothesis.[1]: 68
──
── Final conclusions
── Based on developments after it issued its original report in April 1990, the NTSB issued a superseding accident report on March 18, 1992.[1]: 1–2 In this report, the NTSB determined that the probable cause of the accident was the sudden opening of the cargo door, which was attributed to improper wiring and deficiencies in the door's design. It appeared in this case that a short circuit caused an unordered rotation of the latch cams, which forced the weak locking sectors to distort and allow the rotation, thus enabling the pressure differential and aerodynamic forces to blow the door off the fuselage; ripping away the hinge fixing structure, the cabin floor, and the side fuselage skin; and causing the explosive decompression.[8]
── the weakest link principle (Murphy's law): improper wiring ==> short circuit ==> ? ciruit breaker trip ? ==> unorder rotation of the latching cams ==> weakening of the locking mechanism ==> pressure differential ==> blow the cargo door off the fuselage ==> ripping away the hinge structure ==> ...
── Edward Aloysisu Mirchy, Jr. [1917-1990]: “If there is more than one way to do a job, and one of those ways will end in disaster, then someone will do it that way.”──Brian Burrell, The words we live by [1997], pp.146─149
____________________________________
── takes about two decades to fix known problem;
── the ... industry can resist fixing the root cause of known problem for about two decades;
── more like a function of tomestone technology;
── for some problems to be fixed, enough people have to die, the information has to be made public, and the investigative journalists/reporters have to tell a compelling story to exceed a minimum threshold in repetition, exposure, and ... to start the ball rolling;
── it also takes about two decades for enough people to die and enough cases to build up to make a compelling pressure for changed; would be nice if we can do better; ...
── however, if the industry like (1) Tobacco & cigarrete with cancer [United States][interesting because of UK healthcare system, they did not have this problem], (2) Petroleum & Fossil fuel industry with global warming, and (3) Chemical company with a insecticide [European union], the Industry can delay change for over two decades, stay in business, maintain the revenue stream, and accumulate the body count; ...
── the three cases, four cases if you add aircraft industry, fit the classic principle of concentrated benefit over diffuse harm; the industries gain concentrated benefit if they can delay change, and the harm is diffuse, making situation difficult for the Public, the Regulator, the Law, and the Representatives to gather enough evidence to implement change, without falling into false positive diagnosis (thinking the industry has screw up, when in fact, they did not).
── the industry is focus, determine, have the incentive to delay and maintain steady-state to not rock the boat, keep the gravy train running;
── yes, you will make less money, but guess what, you are preventing all the suffering, saving all those lives that does not have to die, and you are not going to get that bonus; hmmm ...
____________________________________
concentrated benefit over diffuse harm
Written by John W. Gofman and Egan O'Conner *14
([ --> principle of concentrated benefit over diffuse harm <-- ])
“The law of Concentrated Benefit over Diffuse Injury can be stated as follows:
“A small, determined group, working energetically for its own narrow interests, can almost always impose an injustice upon a vastly larger group, provided that the larger group believes that the injury is "hypothetical," or distant-in-the-future, or real-but-small relative to the real-and-large cost of preventing it.
[...]
“Many scholars have written about this extremely important axiom before —— it is not original with us. The fact that narrow special interests are always at work for their own benefit at the expense of others is not at all surprising, given human nature. And it is not surprising that the victims select what appears to be the strategy of least cost to themselves.
“The surprising aspect is the failure of so many victims —— especially in peaceful democracies —— to appreciate the aggregate consequences which inevitably accrue, when each small injustice has such a high chance of prevailing.”
*14 (
http://www.ratical.org/radiation/CNR/CBoDI.html
)
____________________________________
--> principle of concentrated benefit over diffuse harm <--
____________________________________
John Bartlett.──17th ed., Bartlett's familiar quotations, 2002
p.852:10
p.852
10 “Murphy's Law”: if something can go wrong, it will.
saying [1950s]3
3 included in Arthur Block's collection of popular saying, Murphy's Law [1977]. In its original form [1949] by Edward Aloysisu Mirchy, Jr. [1917-1990]: “If there is more than one way to do a job, and one of those ways will end in disaster, then someone will do it that way.”──Brian Burrell, The words we live by [1997], pp.146─149
( Bartlett's familiar quotations : a collection of passages, phrases, and proverbs traced to their sources in ancient and modern literature / John Bartlett; edited by Justin Kaplan.──17th ed., rev. and enl., 1. quotation, English, PN6081.B27 1992, 808.88'2──dc20, 2002, )
____________________________________
Peter Robinson, flying blind : the 737 max tragedy and the fall of boeing, 2021
pp.30-31
p.30
The first crash of one of the new fully loaded wide-body planes was an international scandal, provoking newspaper coverage of shocking design lapses, televised congressional hearings, and even a full-length book exposé. Soon after the plane's takeoff from Paris Orly airport in March 1974, an explosion blew out the cargo door, buckling the floor and severing hydraulic lines. All 346 people aboard died when the plane plunged into Ermenonville forest outside Paris, the worst airliner crash in history at the time. Debris was scattered for half mile through wooded trails popular with Sunday hikers.
The plane was a DC-10, a slightly smaller wide-body McDonell Douglas had developed to keep up with Boeing's 747.
https://en.wikipedia.org/wiki/Turkish_Airlines_Flight_981
March 3 – Turkish Airlines Flight 981, a McDonnell Douglas DC-10, crashes in the Ermenonville forest near Senlis, France, after the rear underfloor cargo door opens in mid-flight; all 346 on board die.
p.30
To save valuable interior cargo space, they broke with industry convention by designing a door that opened outward.
pp.30-31
It emerged that Douglas engineers had known the design was vulnerable to catastrophic failure, and indeed, two years earlier, a near disaster had ensued on a flight over Windsor, Ontario, which also lost a cargo door. The pilot had been able to land the plane in that case.
p.30
..., Mr. Mac holding the purse strings as tightly as ever.
p.31
Instead of fixing the issue immediately, McDonnell Douglas had convinced the FAA to let it add a support plate over time to the doors ── a “gentlemen's agreement” revealed in the congressional hearings. Records at Douglas showed that the support plate had been added to the Turkish airlines plane, when it had not. Three company inspectors had signed off on the nonexistent fix.
(Flying blind : the 737 max tragedy and the fall of boeing / peter robinson.
new york : doubleday, 2021, bibliographical references and index., (ebook), (hardcover), (trade paperback), (ebook), boeing company──management.|boeing 737 (jet transport)──accidents.|aircraft industry──united states──management.|aircraft industry──united states──employees.|corporate culture., HD9711.U63 (ebook), 338.7/6291300973──dc23, 2021, )
____________________________________
McDonnell Douglas DC-10 flight over Windsor, Ontario
<< look up this near disaster flight >>
https://en.wikipedia.org/wiki/American_Airlines_Flight_96
Date June 12, 1972
Summary Cargo door failure due to design flaw leading to rapid decompression
Site Airspace above Windsor, Ontario
Aircraft type McDonnell Douglas DC-10-10
The rapid decompression in the cargo hold caused a partial collapse of the passenger compartment floor, which in turn jammed or restricted some of the control cables which were connected to various flight control hydraulic actuators. The jamming of the rudder control cable caused the rudder to deflect to its maximum right position. The control cables to the number two engine in the tail were severed, causing that engine to shut down.[1] There was no rupture of any hydraulic system, so the pilots still had control of the ailerons, the right elevator, and the horizontal stabilizer.
The cause was traced to the cargo door latching system, which had failed to close and latch the door completely without any indication to the crew that it was not safely closed. A separate locking system was supposed to ensure this could not happen but proved to be inadequate. McDonnell Douglas instituted a number of minor changes to the system in an attempt to avoid a repeat. These were unsuccessful, however; on March 3, 1974, the rear cargo door of Turkish Airlines Flight 981 experienced the same failure and blew open, causing the aircraft to lose all control and crash in a forest near Paris, France. This crash killed all 346 people on board, making it the deadliest in aviation history until the 1977 Tenerife airport disaster and the deadliest single-aircraft crash until the 1985 crash of Japan Airlines Flight 123.[3]
In the cabin, the flight attendants saw a "fog" form within the cabin and immediately recognized it as a depressurization.
It happened that while training to convert his expertise to flying the DC-10, McCormick had practiced, in a simulator, controlling the plane with the throttles in this fashion, in the worst-case scenario of a hydraulic failure.[2] A similar technique was used on another DC-10 in 1989 following a complete loss of hydraulic pressure on United Airlines Flight 232.[6]
The cabin floor failure was also a matter of poor design. All of the other portions of the cargo holds had holes cut into the cabin floor above the cargo areas. In the case of a pressure loss on either side of the floor, the air would flow through the vents and equalize the pressure, thereby eliminating any force on the floor. Only the rearmost portion of the cabin lacked these holes, and it was that portion that failed. Because the control cables were running through the floor for the entire length of the aircraft, however, a failure at any point on the floor would cut controls to the tail section.
____________________________________
Douglas engineers had known the design was vulnerable to catastrophic failure, and indeed, two years earlier, a near disaster had ensued on a flight over Windsor, Ontario, which also lost a cargo door. The pilot had been able to land the plane in that case.
https://en.wikipedia.org/wiki/List_of_accidents_and_incidents_involving_commercial_aircraft#1974
https://en.wikipedia.org/wiki/Turkish_Airlines_Flight_981
Date 3 March 1974
Summary Cargo door failure due to aircraft design flaw leading to explosive decompression, destruction of control systems, and loss of control
Site Ermenonville Forest, Fontaine-Chaalis, Oise, France
Aircraft type McDonnell Douglas DC-10-10
March 3 – Turkish Airlines Flight 981, a McDonnell Douglas DC-10, crashes in the Ermenonville forest near Senlis, France, after the rear underfloor cargo door opens in mid-flight; all 346 on board die.
Just after the aircraft passed over the town of Meaux, the rear left cargo door blew off and the sudden difference in air pressure between the cargo area and the pressurized passenger cabin above it, which amounted to 36 kPa (5.2 psi),[9]: 44 caused a section of the cabin floor above the open hatch to separate and be forcibly ejected through the open hatch,
When the door blew off, the primary as well as both sets of backup control cables that ran beneath the section of floor that blew out were completely severed, destroying the pilots' ability to control the plane's elevators, rudder, and number two engine. The flight data recorder showed that the throttle for engine two snapped shut when the door failed.[9]: 26 The loss of control of these key components resulted in the pilots losing control of the aircraft entirely.
The Lloyd's of London insurance syndicate that covered Douglas Aircraft retained Failure Analysis Associates (now Exponent, Inc.) to also investigate the accident. In the company's investigation, it was noted that during a stop in Turkey, ground crews had filed the cargo door's locking pins down to less than a quarter of an inch (6.4 millimetres), when they experienced difficulty closing the door. Subsequent investigative tests proved the door yielded to approximately 15 psi (100 kPa) of pressure, in contrast to the 300 psi (2,100 kPa) that it had been designed to withstand.[13]
The cargo door design flaws, and the consequences of a likely aircraft floor failure in the event of in-flight decompression on the DC-10, had been noted by Convair engineer Dan Applegate in a 1972 memo.[14] The memo was written after American Airlines Flight 96, being operated by another DC-10, experienced a rear cargo door failure similar to the one that occurred on Flight 981, also causing an explosive decompression. Fortunately, even though the pilots' ability to control Flight 96 was compromised by some severed underfloor cables in the damaged section of the plane, they were able to land in Detroit without further injuries – though Applegate warned that a more severe outcome was likely when (not if) a similar incident happened on another DC-10.
Although French media outlets called for Mahmoudi to be arrested, the crash investigators stated that it was unrealistic to expect an untrained, low-wage earning baggage handler, who could not read the warning notice, to be responsible for the safety of the aircraft.
This possibility of catastrophic failure as a result of this overall design was first discovered in 1969 and actually occurred in 1970 in a ground test, both of which McDonnell-Douglas knew about. This information, and the 1972 "Applegate Memo", came to light in the material supplied to the litigants after the 1974 crash.[16] McDonnell-Douglas had ignored these concerns, because rectification of what Douglas considered to be a small problem with a low probability of occurrence would have seriously disrupted the delivery schedule of the aircraft, likely causing Douglas to lose sales.
Additionally, the FAA ordered further changes to all aircraft with outward-opening doors, including the DC-10, Lockheed L-1011, and Boeing 747. These changes included requiring vents be cut into the cabin floor to allow pressures to equalize in the event of a blown-out door, thus preventing a catastrophic collapse of the aircraft's cabin floor and other structures that could damage the control cables for the engine, rudder, and elevators.
Aircraft other than DC-10s have also suffered catastrophic cargo hatch failures. The Boeing 747 has experienced several such incidents, the most noteworthy of which occurred on United Airlines Flight 811 in February 1989, when a cargo hatch failure caused a section of the fuselage to burst open, resulting in the deaths of nine passengers who were blown out of the aircraft.[21]
____________________________________
https://en.wikipedia.org/wiki/United_Airlines_Flight_811
• on February 24, 1989, United Airlines Flight 811, a 747-100, which suffered an explosive decompression in mid-flight. killing 9 of 355.
N4713U
The aircraft had been flying for 17 minutes,[1]: 25 as it was passing from 22,000 to 23,000 feet (6,700 to 7,000 m), when the flight crew heard a loud "thump", which shook the plane. [1]: 2
About a second and a half later, the forward cargo door blew off. It swung out with such force that it tore a hole in the fuselage. Pressure differentials and aerodynamic forces caused the cabin floor to cave in, and 10 seats (G and H of rows 8 through 12) were ejected from the cabin.[1]: 8 [8] All eight passengers seated in these locations were killed, as was the passenger in seat 9F. Seats 8G and 12G were unoccupied.[1]: 109 [8] A gaping hole was left in the aircraft, through which a flight attendant, Mae Sapolu in the business-class cabin, was almost blown out. Purser Laura Brentlinger hung on to the steps leading to the upper deck, and was dangling from them when the decompression occurred. Passengers and crew members saw her clinging to a seat leg and were able to pull her back inside the cabin, although she was severely injured.[8]
The debris ejected from the aircraft during the explosive decompression damaged the Number 3 and 4 engines.[1]: 4–8
The NTSB looked to circumstantial evidence, including prior incidents that involved cargo doors. In 1987, Pan Am Flight 125, another Boeing 747, outbound from London Heathrow Airport, encountered pressurization problems at 20,000 feet (6,100 m), causing the crew to abort the flight and return to the airport.[1]: 57 [11] After the safe landing, the aircraft's cargo door was found to be ajar by about 1.5 inches (3.8 cm) along its ventral edge.
Based on the evidence available, and the attribution of prior cargo-door malfunctions to damage and ground crew mishandling, the NTSB operated from an assumption that a properly latched and locked 747 cargo door could not open in flight:[10]: 37
N4713U
The NTSB learned that in N4713U's case, the aircraft had experienced intermittent malfunctions of its forward cargo door in the months prior to the accident.[10]: 51
Focusing on damage to the door and maintenance procedures, the NTSB concluded that the accident was preventable human error, and not a problem inherent in the design or function of the aircraft's cargo door.
Lee Campbell, a New Zealander returning home, was one of the fatalities on Flight 811. After his death, his parents Kevin and Susan Campbell investigated the cause using documents obtained from the NTSB.[12] The Campbells' investigation led them to conclude that the cause of the accident was not human error, but rather the combination of an electrical problem and an inadequate design of the aircraft's cargo door-latching mechanism. They later presented their theory to the safety board.[13]
The Boeing 747 was designed with an outward-hinging door, unlike a plug door which opens inward and jams against its frame as the pressure drops outside, making accidental opening at high altitude impossible. The outward-swinging door increases the cargo capacity, but requires a strong locking mechanism to keep it closed. Deficiencies in the design of wide-body aircraft cargo doors were known since the early 1970s from flaws in the DC-10 cargo door.[14][15] These problems were not fully addressed by the aircraft industry or the NTSB, despite the warnings and deaths from the DC-10 accidents[16] and attempts by Boeing to solve the problems in the 1970s.[failed verification]
On September 26 and October 1, 1990, two halves of Flight 811's cargo door were recovered from the Pacific Ocean from 14,100 feet (4,300 m) below the ocean surface. The cargo door had fractured lengthwise across the center. Recovery crews reported that no other debris or evidence of human remains had been discovered.[17] The NTSB inspected the cargo door and determined that the condition of the locking mechanism did not support its original conclusions.[1]: vi
Additionally, in 1991, an incident occurred at New York's John F. Kennedy International Airport involving the malfunction of a United Airlines Boeing 747 cargo door.[18]
https://www.ntsb.gov/doclib/recletters/1991/a91_83_84.pdf
https://web.archive.org/web/20121008002504/https://www.ntsb.gov/doclib/recletters/1991/A91_83_84.pdf
In the process of diagnosing the cause of a circuit-breaker trip, an inadvertent operation of the electric door latch mechanism caused the cargo door to open spontaneously despite being closed. An inspection of the door's electrical wiring discovered insulation breaches, and isolating certain electrical wires allowed the door to operate normally again.[1]: 66–68
The lock sectors, latch cams, and latch pins on the door were inspected, and did not show any signs of damage of the type predicted by the NTSB's original hypothesis.[1]: 68
Final conclusions[edit]
Based on developments after it issued its original report in April 1990, the NTSB issued a superseding accident report on March 18, 1992.[1]: 1–2 In this report, the NTSB determined that the probable cause of the accident was the sudden opening of the cargo door, which was attributed to improper wiring and deficiencies in the door's design. It appeared in this case that a short circuit caused an unordered rotation of the latch cams, which forced the weak locking sectors to distort and allow the rotation, thus enabling the pressure differential and aerodynamic forces to blow the door off the fuselage; ripping away the hinge fixing structure, the cabin floor, and the side fuselage skin; and causing the explosive decompression.[8]
• American Airlines Flight 96 – rapid decompression caused by a cargo door malfunction
https://en.wikipedia.org/wiki/American_Airlines_Flight_96
• Turkish Airlines Flight 981 – explosive decompression caused by a cargo door malfunction
https://en.wikipedia.org/wiki/Turkish_Airlines_Flight_981
• Aloha Airlines Flight 243 – explosive decompression caused by metal fatigue in the fuselage
https://en.wikipedia.org/wiki/Aloha_Airlines_Flight_243
• British Airways Flight 5390 – explosive decompression caused by an improperly installed windscreen
https://en.wikipedia.org/wiki/British_Airways_Flight_5390
• 1975 Tân Sơn Nhứt C-5 accident – loss of control caused by failure of locking mechanism for the aft pressure door
https://en.wikipedia.org/wiki/1975_T%C3%A2n_S%C6%A1n_Nh%E1%BB%A9t_C-5_accident
____________________________________
“the never-ending challenge” by H. G. Rickover
metals engineering quarterly
february, 1963
pp.1-6
Progress ── like freedom ── is desired by nearly all men, but not all understand that both come at a cost.
... ... ...
... ... ...
In any advancing society some elements will accept the advantages of life at a higher plateau yet ignore its obligations.
... ... ...
... ... ...
What is needed is an atmosphere, a subtle attitude, an uncompromsing insistence on excellence, as well as a healthy pessimism in technical matters, a pessimism which offsets the normal human tendency to expect that everything will come out right and that no accident can be foreseen ── and forestalled ── before it happens.
... ... ...
... ... ...
I submit we must progress, and we must pay the price of progress. We must accept the inexorably rising standards of technology and we must relinquish comfortable routines and practices rendered obsolete because they no longer meet the new standards.
This is our never-ending challenge.
metals engineering quarterly
february, 1963
Rickover's speech at the National Metal Congress
new york, 1962, “the never-ending challenge”
source:
https://www.slideshare.net/hammankd/neverendingchallengeasm
(access 2022-09-01, website up)
Theodore Rockwell., The rickover efffect : how one man made a difference / 1992,
(The rickover efffect : how one man made a difference / Theodore Rockwell., 1. rickover, hyman george., 2. nuclear submarines ── united states ── history.
3. admirals ── united states ── biography., 4. united states., navy──biography, V63.R54R63 1992, 359.3'2574'092--dc20, united states naval institute, Annapolis, Maryland, 1992 )
____________________________________
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