Brent VanFossen, Engineer with a View

The Seattle Times has been running a series called “Building the 787″ and recently an article on “When Lightning Strikes” caught my attention.

The article outlines the new technologies and improvements Boeing is making in the 787 involving lightning strikes. While new protection systems prevent many problems associated with lightning strikes, the articles states no airline crash has been caused by lightning in more than 40 years, an amazing accomplishment since Boeing estimates “that every commercial airplane is hit by lightning on average about twice a year.”

Boeing engineers designing the 787 face new challenges, since they are building the first commercial airframe made entirely from carbon fiber-based plastic.

The composite airframe will not readily conduct lightning away, as traditional metal ones do.

That means Boeing will have to do more to prevent lightning from damaging the planes, said Ed Rupke, senior engineer with respected consulting firm Lightning Technologies of Pittsfield, Mass.

An airplane often actually triggers a lightning bolt to the nose, the leading edges, the tail or the wings as it flies through an electrically charged cloud. The main danger airplane designers must guard against is sparking inside the wings, which serve as the jet’s main fuel tanks.

Most of the time, after a flash and a bang, lightning damage is minimal, and airplanes fly on to their destinations.

With the new 787 constructed on a plastic airframe with composites, lightning protection becomes a major concern.

After a decade of serious accidents internationally from lightning strikes on aircraft, the FAA increased safety requirements and protection systems in the early 1980s.

What caught my attention the most was the interesting “multilayered approach to lightning protection of the 787 fuel tank” that Boeing is taking. Here are excerpts from the article:

• The initial lightning strike must be dispersed quickly around the airframe to prevent concentrated damage.
• The airplane’s electronic flight instruments must be shielded from disruption by the intense electromagnetic field.
• A slight gap between a wing-skin fastener and the hole it goes into could be a source of sparking as current jumps the gap. Boeing will install each fastener precisely and seal it on the inside to ensure a snug, spark-free fit.
• Any gap inside the wings where the wing skin meets internal structural spars could cause a spraying out of electrons in a lightning strike — a phenomenon called “edge glow.” Boeing will seal the edges with nonconducting goop or glass fiber.
• Boeing will install a nitrogen-generating system (NGS) that reduces flammable vapor in the wing tanks by filling the space above the fuel with inert gas, as a backup in case other methods fail.

The Seattle Times reports on a new “aircraft crawler” developed by Boeing and Nova-Tech Engineering of Lynnwood, Washington, to turn the 777 production line in Everett, Washington, into a form of “moving assembly line”. The old method used cranes to lift the fuselage sections into a fixed structure where all the parts and pieces were installed, and then the crane would move the section to the next phase, a dramatic and hazardous routine. The new crawler will replace the crane and the fixed structure, becoming an assembly line.

They are highly maneuverable, capable of rotating aircraft sections full circle and can expand or contract to fit the different fuselage lengths of various 777 models…

…The fuselage sections will sit in two cradles atop the crawlers, and mechanics standing on attached work platforms will install the systems as they move forward at a rate of 1.8 inches per minute, following a white line on the factory floor…

…Starting sometime in 2007, the crawlers — this time moving at a rate of 10 feet per minute — will also transfer completed fuselage sections from systems installation over to the tooling where the aircraft sections are finally joined together.

This technique will allow Boeing to move heavier aircraft section pieces as the crane has weight limitations. These new crawlers are expected to drop the “work-flow days” from the current 20 days, eventually down to 12.

It seems that Boeing blogger, Randy Baseler, recently stirred up a fuss over his post on Width is Which, about the issue of seat spacing in aircraft. So much so that he had to post a response to all the ruckus.

Airplane interiors - now that’s a topic that really gets people squirming in their seats!

The blog we did a couple of weeks back about the so-called “7 inch” difference between the A320 and the 737 turned out to be one of the more controversial topics we’ve done.

Some people took it quite personally. We’ve now posted your thoughts on the subject in our comments section.

Yes, Randy, people get really uptight about being crammed into airline seats like cattle, especially when food and drinks now come at a premium, and airline travel is becoming more hassle than fun.

But the fact of the matter is, as Randy explains, that seat spacing has little or nothing to do with the aircraft manufacturers and more with the customer’s interior configurations.

To point out the fact that when Airbus talks about “7 inches,” that dimension is on the outside of the A320. And that an outside measurement has little to do with interior comfort.

Yes, the A320 is a wider fuselage. And on the inside, at seat bottom, or knee level, that equates to about 5.8 inches wider - or less than an inch per passenger in six abreast economy class.

There is more to the issue of seat spacing. I’ve worked on many airplanes, new and old, and each airline has their own interior configuration and customization. Some like it tight, some like it spacious. Some want to cram in as many seats as possible, while others want their passengers to have a little more leg and shoulder room. Some want a large business section with more space and others want the whole plane to be a cattle truck. It depends upon the airline and what their specifications are, not necessarily the aircraft itself.

If you are worried, check with the aircraft specifications for each airline before you buy your tickets.

Still, as tall as I am, I long to be able to sit in an airplane and not have my knees jammed against the seat in front of me, pushing me backwards, crushing my spine into my seat.

“Accidents Up and Fatalities Down” reports The Airline Hub via Yahoo News.

Accidents in the United States involving commercial airlines and private aircraft rose last year, but fatalities declined, according to safety figures released on Friday.

The National Transportation Safety Board, which is responsible for investigating transportation accidents, said in its annual review that civil aviation accidents rose to 1,779 last year from 1,717 in 2004…Fatalities fell to 600 last year from 636 in 2004.

Virtually all of the accidents and deaths occurred in general aviation crashes, those involving small planes. The fatal accident rate and the fatality rate both increased for that group of aircraft.

Reuters reports that the “Airline Industry Sees Job Growth, But the Pain Remains”.

Employment prospects for airline workers are better now than at any time since the September 11 attacks, but the slight uptick in demand may not create jobs for all out-of-work airline professionals or lift the industry’s decimated wage structure.

Large carriers such as UAL Corp.’s United Airlines, US Airways and Continental Airlines have been adding staff since last year as competition on some routes has subsided and cost cuts have narrowed losses.

Still, struggling carriers continue to slash labor costs. Bankrupt Delta Air Lines, for example, is laying off thousands as part of its restructuring. Experts say joblessness abounds and compensation is down significantly as airlines struggle to keep costs in check.

“We’re in a hiring situation, not in a furlough situation, but I don’t think that tells the whole story,” said Sara Nelson Dela Cruz, spokeswoman for the Association of Flight Attendants (AFA), which represents flight attendants at United and some smaller carriers.

“It doesn’t tell the story of the thousands of people who were laid off after September 11,” she said. “And it doesn’t tell the story of the thousands of people who had to leave because they could no longer afford to stay in this industry.”

According to US government reports from the Transportation Department, the number of workers at major airlines dropped 21.6 percent from 2000 to 2004 and added 2,800 jobs in 2005, the first increase since 2000. While the domestic airline industry has been hit hard, the international airline industry is booming. While many domestic airlines are blaming high fuel rates and September 11 fallout, then why is the international airline industry not feeling the same heat? Makes one wonder.