* Battery explosion destroyed building in Tucson in 2006
* Investigators plan to visit on Tuesday for tests
* Boeing: '06 fire blamed on test setup, not battery design
By Andrea Shalal-Esa
WASHINGTON, Jan 20 (Reuters) - Tucson, Arizona-based Securaplane Technologies Inc, which makes a charger for batteries used on the Boeing Co's 787 Dreamliner, said on Sunday it would support an investigation into battery issues that have grounded the new planes.
Securaplane, a unit of Britain's Meggitt Plc, first began working on the charger in 2004, but suffered millions of dollars of damages in November 2006 after a lithium-ion battery used in testing exploded and sparked a fire that burned an administrative building to the ground.
The U.S. National Transportation Safety Board on Sunday ruled out excess voltage as the cause of a battery fire on the 787 at the Boston airport this month.
It said investigators would travel on Tuesday to Tucson, Arizona, where Securaplane is based, to test and examine the charger and download memory from the controller for the auxiliary power unit. They also plan to travel to Phoenix and carry out similar tests at the site where a unit of United Technologies Corp builds the power unit.
Fiona Greig, a spokeswoman for Securaplane, said the company had been invited to "contribute to the investigation process" and planned to fully support it.
"In line with the NTSB's practices, however, it would not be helpful to that investigation to comment further," she said in a statement provided to Reuters.
The U.S. Federal Aviation Administration (FAA) on Sunday said it had investigated safety complaints leveled by a former Securaplane employee in 2008 and 2009 but determined that the allegations focused on prototypes that were not ultimately used in the new lightweight airliner.
Shubhayu Chakraborty, president of Securaplane, earlier told Reuters that his company's lithium-ion battery charger was currently only in use on the Boeing 787, although it is developing different systems for use on other aircraft.
Securaplane is building a lithium-ion battery system for the KC-390 military transport plane being developed by Brazil's Embraer SA, which is due to have its first flight in 2014. Embraer declined comment.
The company is also developing backup batteries for the Embraer Legacy 450 and 500 business jets and will make the lithium battery for the next-generation Eurocopter EC-135 helicopter being developed by EADS, according to the company's website.
The charger is part of a complex system that uses a lithium-ion battery made by Japan's GS Yuasa Corp and electrical systems made by France's Thales to provide start-up power for an auxiliary power unit, which is built by Pratt & Whitney, a unit of United Technologies.
A separate lithium-ion battery, which also uses a Securaplane charger and Thales electrical power conversion equipment, is used as a main battery backup for flight critical systems, according to Boeing.
The NTSB's decision to travel to Securaplane's facility sparked fresh questions about a fire that destroyed an administrative building there in 2006.
Boeing spokesman Marc Birtel said an investigation into the 2006 fire at the Securaplane facility was later determined to have been caused by an improper test set-up, not the battery design. He declined comment on the current 787 investigations.
After the fire, a former Securaplane employee named Michael Leon filed a claim for federal whistleblower protection, alleging that he was fired for raising security concerns about the design of the charger and discrepancies between assembly documents for the chargers and the finished chargers.
A federal administrative law judge dismissed Leon's suit in July 2011, saying the company had proven he was fired for repeated misconduct, not any safety complaints. The judge did not rule on Leon's alleged safety concerns.
Greig confirmed the suit was filed and dismissed, but said the company could not discuss personnel issues. She said Leon had appealed to the Labor Department's administrative review board in November 2011, but there had been no ruling.
Leon could not be reached for comment.
FAA spokeswoman Laura Brown said the FAA investigated Leon's complaints, but determined that the battery charging units that he addressed were prototypes, and none were installed in Boeing 787 aircraft.
"Our reviews also determined Securaplane's production of a particular printed circuit board complied with FAA requirements," Brown said.