From where did the TPA flight originate?
Answer
Barker waited patiently for a moment, then said, "The consequence of this design error is that when the slats extend, the airplane noses upward, like this, threatening to stall." He tilted the model up slightly. "At this point, it is almost impossible to control. If the pilot tries to restore the plane to level flight, the plane overcompensates, and goes into a dive. Again, the pilot corrects, to come out of the dive. The plane climbs. Then dives. Then climbs again. That is what happened to Flight 545. That is why people died."

Barker paused.

"Now we're through with the model," he said. "So I'm going to put it down."

"Okay," Jennifer said. She had been watching Barker on the monitor on the floor, and now she was thinking that she might have difficulty cutting the wider shot to the shot of putting the model down. What she really needed was a repetition of -

Barker said, "The plane dives. Then climbs. Then dives again. That is what happened to Flight 545. That is why people died." With a regretful look, he put the model down. Although he did it gently, his very gesture seemed to suggest a crash.

-- Airframe
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In the 6th chapter of "Airframe" Casey Singleton says that "No other manufactured product in the world has the complexity of a commercial aircraft. Nothing even comes close." Is a commercial airplane (e.g. Boeing 747) really more "complex" than a military aircraft? Is a commercial airplane also more complex than a nuclear submarine? By "manufactured product" I am thinking of a commercial object that is manufactured in large numbers on an assembly line, and then sold to buyers. Obviously one can think of many other kinds of objects-a nuclear aircraft carrier, the city of New York, the space shuttle-which could be viewed as more complicated than a commercial jet airplane. But these are essentially one-off, build-to-order creations, and not for sale. Numbers tell the story. Last time I looked, there were something like five nuclear carriers, four space shuttles, and one city of New York. There are thousands of commercial aircraft in the skies. Thus, of "manufactured objects," commercial aircraft are the winner.

But in terms of other manufactured objects, here's why a commercial widebody is said to be the most complex manufactured product in the world:

1. It has a million parts vs five thousand for a car, or about 50 thousand for a military jet. (I don't know the exact number for a military jet but it is nothing like a commercial aircaft. Even military cargo jets are simpler than commercial jets.)

2. The assembly line requires 75 days to complete. This compared to one day for a car, or several days for a military jet. A jumbo jet assembly line employs thousands of workers, an auto line a couple of hundred. A commercial jet requires something like half a million man-hours to build. A car requires 16 man hours. (You get the half million number by the following quickie assumptions. Two shifts of 8 hours each, first shift 5000 workers, second shift 3000 workers. Divide by 10 stations that are labor intensive. Multiply by 75 days, gives you 480,000 man-hours.) 3. The quality demanded at every stage-from the outside suppliers of individual parts, through the assembly methods on the line, through the testing at various points of assembly, and testing of the final aircraft-is vastly greater than anything done for the military, or for any other consumer product. (I mention this because the quality of a given part is a function of the complexity of the manufacturing and testing process that leads to it. Better parts are more difficult to make, requiring more steps and more testing.) 4. The performance specs for a commercial jet far exceed any other manufactured product. Jets are designed to operate for 20 years and they are built to last twice as long. In terms of hours, they are built to go 100,000 hours. You can't operate any other mechanical device in the world-from a stapler to hard drive to a car-for 100,000 hours, even if you service it diligently. The materials in a car or a stapler simply won't stand up to that degree of use.

We don't stop to think how little we use most devices. For example, if your car lasts 200,000 miles, you'd probably think it was pretty rugged. But at an average speed of 30 mph, that's only 6,600 hours of use. To get 100,000 hours, you would have to drive the car 3 million miles. You tell me if you're sure your car-or any car-would make it. But we are sure an aircraft will go that many hours. We rely on it as a matter of course, every time we board a plane.

In summary, if you're aware of any mechanical device that requires more than half a million man hours to build, that is assembled from more than a million parts, and that operates with absolute reliably for more than 100,000 hours, please let me know.

If you have additional questions on this subject, as a journalist you might want to call Boeing.






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