Boeing 747 — The End of an Era?

“Aviation investigations are replete with accident scenarios that couldn’t happen. And given the lack of bomb evidence so far, neither scenario has been ruled out, officials said.

First is the possibility that the doomed plane’s front section, which has a history of structural fatigue cracks and must undergo regular inspections, simply unzipped from the rest of the plane as weakened structural frames gave way.”

Washington Post August 1 1996

Boeing has delivered more than 1,500 of the jets since 1970. Now, the company says  it might stop production of the 747.

AO747

The destruction in flight of three Boeing-747 remains the subject of intense debates to this day: AIR INDIA 182, PAN AM 103, and TWA 800.

AIR INDIA 182

Air India Flight 182 was an Air India flight operating on the Montreal, Canada–London, UK–Delhi, India route. On 23 June 1985, the Boeing 747-237B serving the flight (c/n 21473/330, registration VT-EFO, “Emperor Kanishka”) was destroyed by a bomb at an altitude of 31,000 feet (9,400 m). It crashed into the Atlantic Ocean while in Irish airspace. It was the first bombing of a 747 jumbo jet. A total of 329 people were killed, including 268 Canadian citizens, 27 Britons and 24 Indians. [WIKIPEDIA]

PAN AM 103

The aircraft operating Pan Am Flight 103 was a Boeing 747–121, registered N739PA and named Clipper Maid of the Seas, formerly named Clipper Morning Light prior to 1979. It was the 15th 747 built and was delivered in February 1970, one month after the first 747 entered service with Pan Am. At the time of its destruction, Clipper Maid of the Seas was 18 years of age and had accumulated over 75,000 flying hours. [WIKIPEDIA] The plane had 16497 cycles.

TWA 800

Trans World Airlines Flight 800 (TWA 800) was a Boeing 747-100 which exploded and crashed into the Atlantic Ocean near East Moriches, New York, on July 17, 1996, at about 8:31 p.m. EDT, 12 minutes after takeoff from John F. Kennedy International Airport on a scheduled international passenger flight to Rome, with a stopover in Paris. All 230 people on board were killed in the third-deadliest aviation accident in U.S. territory.

The accident airplane, registration N93119, (Boeing 747-131) was manufactured by Boeing in July 1971; it had been ordered by Eastern Air Lines, but after Eastern canceled its 747 orders, the plane was purchased new by TWA. The aircraft had completed 16,869 flights with 93,303 hours of operation. [WIKIPEDIA]

Intense Debates & Suspicion of Cover-up

The official stories are doubted by very serious people, and for very good reasons I must add. In the case of India Air 182 and Lockerbie, Intelligence Agencies are suspected — at the very least — of withholding crucial information. In the case of TWA 800, the FBI is known to have attempted to hide vital information pointing to a mechanical failure while trying to portray the accident as an act of terrorism.

“FBI’s former chief metallurgist, William Tobin, testified that bureau officials repeatedly and angrily dismissed scientific evidence that pointed to a mechanical malfunction.”

“The FBI didn’t want to hear about anything but a missile or a bomb, because otherwise there was no FBI case,” said Grassley, chairman of the Judiciary subcommittee on administrative oversight. “Their conduct was disturbing from the very beginning.” WP May 9 1999

Old before their time

Wherever the  truth may lie, there is at the very least one fact about these disasters that cannot be disputed: in each case the front section detached from the main body of the plane and  thus landed earlier that the rest of the plane.

In the mid 80′, Boeing had noticed a serious engineering problem with the front section of the Boeing 747. In short, due to the unusual shape of that part of the plane, fatigue effects on the structure of section 41 (and to a lesser extent section 42) were far more severe than anticipated. [The issue was expected but underestimated.]

 

Museum_of_Aeronautical_Sciences_Boeing_747_section41

SECTION 41 OF THE B747

Boeing introduced about two dozen “Airworthiness Directives” requiring immediate inspections and repairs. All 747 planes built after the 686th were constructed according to a new design. It is also said that Boeing switched to a different aluminum-alloy for some critical parts.

Carl A. Davies has researched this issue and published a very interesting book: PLANE TRUTH.

F2

Cracks due to the fatigue effect

Davies points out that the 747 had been expected to serve 20 years, 20,000 cycles or 60,000 hours. But the problems encountered with section 41 made it clear that these expectations were not realistic. In some case, “fatigue cracks” would appear as soon as after just 6,500 cycles.

For what it is worth, I understand that in each of these disasters, the “Black Box” recorded one single loud noise believed to have been caused by the breaking-up of the plane.

REFERENCES

Boeing Considers Ending Production of 747

POSSIBLE MECHANICAL FLAWS PROBED IN FLIGHT 800 CASE

FBI Sought to Suppress Report on TWA Crash

BOOK: PLANE TRUTH – Carl A. Davies

 

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This entry was posted in Bill Tobin, Boeing 747, FBI, INDIA AIR 182, Pan Am 103, TWA 800. Bookmark the permalink.

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