fredag 29. juli 2016

A350 - Will FAA demand stricter demands on the type`s certification? - Curt Lewis

Airbus, FAA Spar Over Lithium Batteries

European regulators approve A350's batteries, but fight continues with U.S. agency over safeguards, testing

Intended to provide backup power for the newest A350 jetliners, lithium batteries are more powerful, lighter and require less maintenance. Above, an A350 aircraft at the Farnborough International Airshow earlier this month. 

By ANDY PASZTOR

European jet maker Airbus Group SE is locked in a dispute with U.S. regulators over the safety of lithium-ion batteries installed on its latest model, according to people familiar with the details.

Escalating arguments about the extent of safeguards and testing for such rechargeable batteries-reminiscent of Boeing Co.'s difficulties with similar technology years ago-come after European regulators already have approved the Airbus systems based on less-stringent requirements.

Intended to provide backup power for the newest A350 jetliners, lithium batteries are more powerful, lighter, require less maintenance and last slightly longer than traditional nickel-cadmium batteries used on other models. But experts say they also are more volatile and without special safety features, more prone to experience short-circuits, overheat and potentially emit smoke or fire.

A green light from the U.S. Federal Aviation Administration has been pending for months, with Airbus officials expressing optimism last fall that a favorable decision was imminent. But according to people familiar with the process, continuing disagreements pitting the manufacturer against FAA technical experts have created a regulatory logjam and delayed approval.

Airbus said "we are working with the FAA on certifying a battery solution," but declined to elaborate.

With the agency continuing to evaluate the matter and no clear timeline for a final decision, the two sides can't seem to agree on precisely what issues are blocking progress.

The crux of the debate for many months, according to two of the people familiar with the details, revolved around the possibility that the FAA would require the batteries to be enclosed in a rugged stainless steel container, similar to those previously mandated for Boeing's flagship 787 jets.

But according to another person familiar with the specifics, such a demand never materialized. This person said the latest argument involves FAA demands to conduct a comprehensive test to determine if the batteries emit smoke or flames after being overcharged.

So far, according to these people, Airbus officials have balked at performing that test and argued instead that probability analyses are adequate to determine safety margins.

The company, according to some of these people, has asserted that it would have to disable built-in overcharge protections to comply with FAA testing requirements-resulting in an unrealistic testing scenario. Airbus also contends its internal battery design differs significantly from those used by Boeing, making the container unnecessary.

The containment hardware is heavy but considered to offer foolproof protection against smoke and flames because it eliminates oxygen from the enclosure and vents all gases outside the aircraft.

The clash is the latest example of broader friction involving various certification and policy issues between regulators on opposite sides of the Atlantic.

The conflicting approaches range from debates spanning black box recorders designed to be jettisoned from aircraft before a crash to mandatory cockpit systems intended to warn pilots when landing jets are about roll off the ends of runways. Airbus officials and European air-safety regulators favor those technologies, while their U.S. counterparts generally are reluctant to formally endorse them.

In an email response Tuesday, Airbus said the lithium batteries "save weight equivalent to one passenger" versus traditional power cells, and A350s haven't experienced any overheating, smoke or uncontrolled temperature increases called "thermal runaways."

Some of the latest arguments over battery safety, which have remained largely behind the scenes, hark back to the controversy that temporarily grounded Boeing's entire 787 Dreamliner fleet in 2013 in the wake of two separate smoldering-battery incidents. Led by the FAA, regulators world-wide banned the planes from flying passengers for several months until Boeing and agency experts agreed on a range of fixes. They included internal design changes and the beefed-up stainless steel containers.

European regulators already have approved the A350's lithium batteries without all of those extensive protective features and tests. U.S. carriers need the FAA to separately sign off before they can operate the planes. American, United and Delta all have A350s on order, though they aren't slated to arrive for years.

Airbus, for its part, has told the FAA that its batteries are smaller, contain less energy and are less prone to overheat than Boeing's lithium-ion batteries.

When the FAA initially certified the 787 jet, agency and industry officials concluded it would be virtually impossible for the batteries to dangerously overheat. But since some of the original technical assumptions and testing protocols turned out to be wrong, the FAA is now determined to avoid a repeat of those slipups.

Patrick Ky, Europe's top air-safety official, has talked about tempering collaboration with the U.S. "Let's not be completely naive" about working in tandem on everything with industry and regulators from both sides of the Atlantic, he told an international safety conference in Washington last month. "At the end of the day," he added, regulators "must have the power to make decisions."

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