ON THE FLY

· Lithium Batteries May Cause Fires

Although UPS has so far declined to confirm just what was on board the DC-8, the NTSB probe is looking at whether lithium ion batteries, of the type used to power laptop computers, might have caused the fire. Although problems are statistically rare (339 battery-related fires out of the tens of millions of batteries in service) they can have spectacular results.

An exploding cellphone battery is blamed for causing $100,000 in damage to a California home last year and two years ago the FAA banned non-rechargeable lithium batteries as cargo on passenger planes because it found that halon, the fire suppressant used in jetliners, couldn't put out a lithium fire. The rechargeable type most commonly found in consumer electronics are made differently and are considered safer but, according to the Chicago Tribune, the FAA said it had "concerns" about carrying the rechargeable type on airliners.

UPS says it followed all the rules when it loaded the DC-8, including notifying Philadelphia airport authorities of the hazardous materials on board. The company would not disclose the list, however. "We operated according to federal regulations," Frank Skubis, UPS's director of safety, told the Philadelphia Inquirer. "We intend to continue to do that."

· Exploding Fuel Tanks -- Fixes Not Enough

Meanwhile, the NTSB says that earlier fixes aimed at preventing sparks from igniting vapors in aircraft fuel tanks don't work. In a news release last week, the board said the wing tank of a Transmile Boeing 727 exploded even though it had been properly fitted with electrical shields designed to prevent the electrical arcing that most likely ignited the vapors.

An airworthiness directive required the wiring harness in question to be inspected, repaired and then wrapped in plastic before being returned to the conduit in the wing tank. "This accident illustrates that ignition sources continue to exist and fuel tank explosions continue to occur in both wing and center wing fuel tanks despite the corrective efforts of government regulators and industry," the board concluded.

The accident happened while the plane was on the ground at Bangalore, India, and no one was hurt. But the blast wrecked the wing and the plane would have crashed had it been airborne, the NTSB said. The board continues to press the FAA to require systems that displace the explosive vapors in fuel tanks with inert gases, such as nitrogen. Boeing has already designed and installed systems on several aircraft and can retrofit airliners for between $100,000 and $300,000 each, depending on the size.

· Avgas Ethanol Exemption Sought

Both AOPA and EAA are lobbying Congress to exempt aviation gasoline from two proposed amendments to the Clean Air Act. The bills propose making it mandatory for all motor vehicle gasolines (with a few exceptions for collector cars) to contain at least 10 percent "renewable fuels" by 2010.

About the only viable alternative fuel now available is ethanol fermented from corn and it gives airplanes a major hangover. Separate studies by EAA, the FAA and Cessna have conclusively determined that ethanol damages everything from engines to fuel systems in airplanes, but the bills, as they stand now, would require the 10 percent quota for avgas.

The groups are also hoping to get some relief for those with mogas STCs. In addition to exempting avgas, the groups want Congress to allow premium automotive fuel to be made without ethanol. The addition of ethanol invalidates the mogas STCs. Several states have seen the wisdom of having some alcohol-free fuel available, not only for airplanes but for boats and recreational products, and have exempted premium fuel from their own 10-percent rules.

· Lightning Protection Bloats 787

Boeing engineers say its 787 Dreamliner is gaining weight as they figure out ways to shed the enormous shock a lightning strike would bring to the airliner's (nearly) all-composite airframe. Lightning strikes one or two airliners every year and it's not normally a big deal. The big charge just passes through the very conductive aluminum. But in a mostly composite airplane like the Dreamliner, the enormous charge looks for a relatively few conductive paths, such as hinges, attachment points and wiring, and it can vaporize or fuse them.

The answer is to provide conductive routes through the composite and that's where the weight gain comes in for the efficiency-driven design, according to a report in the Seattle Post-Intelligencer. Metal strips or mesh can be added to the layers of composite to ensure the electricity has a place to go. That has pushed the airliner 2.5 percent beyond its "target weight," although Boeing officials insist the plane will not weigh more than what was promised customers. Most of the weight gain is in the wings, which carry the fuel and where electrical arcing is particularly dangerous.

"We always planned to deal with this issue, but we did not anticipate the complexity," Boeing's Scott Strode, head of 787 development and production told, the Post-Intelligencer.