"Have you looked at a modern airplane? Have you followed from year to year the evolution of its lines? Have you ever thought, not only about the airplane but about whatever man builds, that all of man's industrial efforts, all his computations and calculations, all the nights spent over working drafts and blueprints, invariably culminate in the production of a thing whose sole and guiding principle is the ultimate principle of simplicity?" — Antoine de Saint Exupery, Wind, Sand and Stars, 1939.

But anyone could fly a 757 — even a nonpilot, under ideal conditions.

Advancing technology, be it in an airplane, a telephone system or a computer program, often seeks simplicity through complexity. It's not a new idea.

In fact, 44 years ago the French aviator and philosopher Antoine de Saint Exupery blessed technology for making airplanes that pilots could fly as if by second nature. Looking back at earlier flying machines, he wrote:

"There was a time when a flyer sat at the center of a complicated works ... The indicators that oscillated on the instrument panel warned us of a thousand dangers. But in the machine of today we forget that motors are whirring. The motor, finally, has come to fulfill its function, which is to whirr as a heart beats-and we give no thought to the beating of our heart."

Saint Exupery disappeared during a flight over the Mediterranean in 1944 But his "ultimate principle of simplicity" is evident in the aircraft of today.

"We consistently have found that the best (cockpit) displays are the ones which are kept simple in appearance and function," said H.G. Stoll, senior project engineer for the flight deck used in the Boeing 757 and 767. "The crew procedures are simple and the workload is the lowest of any commercial airplane."

NEVERTHELESS, a new-generation jetliner is "about the most complex piece of mechanical equipment that man's ever made," said John Swihart, a Boeing engineer who rose to become vice president of domestic sales.

"My expertise is only in airplanes and some nuclear stuff, and I can tell you that no nuclear reactor is anything as complicated as a commercial airplane, by quite a little bit," he said.

Phil Condit, former director of engineering on Boeing's 757 program, estimated it would take the combined knowledge of 50 to 100 hand-picked engineers to know what is necessary to design a 757 or a similar airplane. Perhaps even that is an underestimate, because many engineers might rely on assistants for important detail information, he said.

Bill Robison directs manufacture of the 757 and is well-acquainted with the immense task of bringing a plane together. He estimates it would take 50 of the supervisors who work for him, pooling their knowledge and experience, to know how to manufacture a new jetliner like the 757.

If those figures seem high, consider that at one point more than 10,000 Boeing employees were assigned to the 757 program and similar number of non-Boeing workers were employed through subcontractors. At its peak, the program employed about 1,500 engineers and a like number of engineering-support personnel.

Modern jetliners incorporate a wide range of technologies. The 757 and 767, for instance, use super-light composite materials created by advanced and sometimes secret processes, a new aerodynamic wing design that resulted from more than 26,000 hours of wind-tunnel testing and sophisticated new electronic systems.

An airplane has been described as a large number of spare parts flying in close formation. In the case of the 757, there are about 3 million parts, held together by about 415,000 fasteners, many of them expensive titanium rivets. There are about 95,000 separate part types.

The plane's 130 on-board microprocessors control everything from cabin pressure to flight path. Many are substantial computers which communicate among themselves, using a "party line" arrangement.

The plane's electrical and electronic systems, including the microprocessors, are interconnected by 37, 857 individual wires totaling 65.9 miles in length and weighing a total of 2,646 pounds.

The 757 also carries a host of intricate mechanical contraptions. Its two British-made Rolls Royce engines each deliver 37,400 pounds of take-off thrust, and represent an enormous investment of time, money, and technology.

"Nobody will develop an engine these days for under $1 billion," said John Hodson, a vice president of Rolls Royce. It could take a team of 300 engineers five years to refine engine technology and new developments into a new engine, and the engineering force might rise to 2,000 at the peak of development, he said.

"You've got enormous energies involved in an engine," Hodson said. To dissipate the heat, the turbine blades must have tiny cooling-air passages running through them-and yet the blades remain strong.

To meet such design and production challenges, high-technology tooling and testing equipment is necessary. "The facilities that you need cost millions and millions of dollars," Hodson said.

Since air flows through a jet engine at high velocities, internal parts must be designed with aerodynamic and vibrational characteristics in mind. Layer up on layer of blades must resonate at appropriate frequencies. The wrong vibration frequency at cruise speed could create a fatigue failure within minutes and "the blade would just fall off," Hodson said.

AS WITH THE entire airplane, sophistication has yielded simplicity of operation in the engines. They require little attention from the 757's two pilots. Computers monitor engine operation, and although the pilots watch a few engine indicators on cockpit video screens, they can mostly ignore the engines unless a problem develops.

The "ultimate principle of simplicity" extends to the maintenance of the 757, too.

On-board electronic systems are in modules, and built-in computers tell maintenance workers which modules, or boxes, should be replaced to get a plane flying again almost immediately. Boxes removed from the planes are taken to repair shops where more new technology is used to diagnose and repair problems.

So, the 757 is an amalgamation of hardware that can be repaired quickly by maintenance personnel who may not really understand what they are repairing, and flown by pilots who may have little grasp of the technology they command.

Consider, for instance, the plane's inertial-reference unit, a device made by Honeywell that uses a trio of lasers to perform navigational feats which in older planes were performed, less precisely, by a gyroscope.

The IRU, as it is called, keeps track of the 757's vertical and horizontal accelerations and decelerations, and by adding and subtracting is able to deduce the altitude and location of the plane. The IRU is so sensitive that it detects the effects of wind and displays wind speed and direction on a cockpit video screen.

A 757 pilot will know how the IRU helps him fly the plane. He will know there are three IRUs cross-checking each other, and that if all agree precisely regarding the 757's location, he can use them to land the airplane automatically in fog.

But will he really understand how and IRU works?

John Armstrong, 757 chief test pilot, explained the IRU this way:

"There are no moving parts. It's a triangular-shaped device and they have a laser beam and they measure the bending of the beam itself. You set in your position before you start moving. Then, as you move around, it keeps track of the position you're at. It can tell where you are any place on the globe."

Armstrong paused, and then captured the essence of both the IRU and the 757 in a phrase:

"It's sort of complicated."

Part  1 |  2 |  3 |  4 |  5 |  6 |  7 |  8