By Andy Pasztor
Three years after fire-prone lithium batteries led to the temporary grounding of Boeing Co.'s flagship 787 fleet world-wide, U.S. regulators are ratcheting up safety standards, as they approve use of various types of lithium power cells on different airliners and business aircraft.
Reflecting this new approach, the recent approvals cover nonrechargeable lithium batteries, which industry officials said are used to power everything from emergency exit signs to cockpit equipment to emergency underwater locator devices. The batteries that prompted so much public attention on 787 Dreamliners, by contrast, are larger, more powerful and rely on rechargeable technology to provide backup electric power.
Still, government documents highlight that many of the identified risks are similar between the two categories of batteries. U.S. regulators are relying on lessons learned from earlier problems with 787 batteries to spell out safety rules for a wider array of new applications for nonrechargeable versions on a number of other models.
Details of the Federal Aviation Administration's decisions reflect that "everyone is now much, much more aware of the issue" in the wake of the prominent incidents with Boeing 787s, according to Joe DePete, who heads up safety efforts at the Air Line Pilots Association.
Lithium batteries are lighter, contain more energy and generally require less maintenance than nickel-cadmium or other traditional batteries. But experts describe them as more flammable, and recognize they may be prone to internal short-circuits, overcharging or other malfunctions that can result in fires or explosive release of gases.
When the FAA initially approved the 787 battery systems for backup power, both government and industry officials relied primarily on engineering and mathematical analyses to support Boeing's conclusions that the batteries wouldn't smolder or catch fire even under operations considered extremely remote.
Ultimately, Boeing was forced to redesign its 787 batteries by installing them inside rugged metal, fireproof containers that preclude flames or hazardous chemicals escaping under any circumstances, regardless of how unlikely those might be. Venting tubes are intended to carry smoke, flames or vapors outside the plane.
Now, U.S. regulators are mandating similarly tough safeguards and fail-safe conditions for other applications. Over the past two weeks, the FAA has issued or proposed rules, known as "special conditions," spelling out strict safety standards for nonrechargeable lithium batteries for certain Boeing 737 jets; cargo and tanker versions of the company's 767 models; and some modified, propeller-powered PC-12 business aircraft originally manufactured by Pilatus Aircraft Ltd.
In every case, the FAA is requiring safety systems able to be certified to keep dangerously high temperatures, flames or gases from damaging aircraft under any circumstances.
As part of its 767 rules, for instance, the FAA said battery designs should be intended "to eliminate the potential for uncontrolled failures." But since "a certain number of failures will occur due to various factors beyond the control of the designer," according to the document, other safeguards are needed "to protect the airplane and its occupants if failure occurs."
The agency also determined that such protections are essential, partly because "service history shows that battery failure is not extremely remote."
The FAA and European plane maker Airbus Group SE are locked in a dispute over rechargeable lithium batteries used for backup power on the latest versions of A350 jetliners. European regulators have signed off on the design, which Airbus contends has more built-in safeguards than rechargeable batteries used on 787s. Airbus is balking at FAA demands that the batteries should be encased in the same type of protective metal shielding now required for 787 jetliners.
The moves come as a joint industry-government panel, under the auspices of the FAA's outside technical advisory organization, is wrapping up work on comprehensive new standards for lithium batteries. The result is expected to be tougher laboratory testing requirements before new systems go into service.
Write to Andy Pasztor at firstname.lastname@example.org