"However, to date, the root causes of the two recent industry Li-ion main batteries incidents remain unexplained to the best of our knowledge," Airbus continued. "In this context, and with a view to ensuring the highest level of [program] certainty, Airbus has decided to activate its 'Plan B' and therefore to revert back to the proven and mastered nickel cadmium main batteries for its A350 XWB [program] at Entry into Service (EIS)."
Airbus, which is based in France, said it will continue testing the A350 with "qualified" lithium ion batteries. However, the company said it considers using non-lithum batteries "to be the most appropriate way forward in the interest of [program] execution and A350 XWB reliability."
The Airbus statement drew a quick response from Boeing, which is the largest U.S.-based airplane manufacturing company.
"Boeing is confident in the safety and reliability of lithium-ion batteries," Boeing said in a statement Friday afternoon. "Our years of experience and deep expertise confirm that, like other technologies, when the appropriate battery, system and airplane protections are in place, lithium-ion batteries deliver significant benefits."
Boeing added that it is "deeply involved with the appropriate investigation authorities in developing a full understanding of two recent battery events."
The company said it was "working tirelessly to create the solutions that will allow the 787 fleet to return to full flight status.
"There's nothing we've learned in the investigations that would lead us to a different decision regarding lithium-ion batteries," the Boeing statement concluded.
The incidents that led to the 787 being grounded by the FAA last month include a pair of lithium batteries that were defective, sparking at least one onboard electrical fire.
The FAA ordered U.S. airlines to stop flying the 787 after smoke was seen during a flight that was originating in Japan. Other worldwide aviation agencies quickly followed suit, leading to a worldwide shutdown of the airplane.
The National Transportation Safety Board (NTSB), which is conducting its own 787 investigation, has attributed the battery fires to short-circuiting and accelerated temperature increases known as "thermal runaway."
The NTSB has additionally questioned the FAA's original certification of the Dreamliner airplane.
Boeing has argued that the vet of the airplane was "rigorous," and the company has maintained the 787 will be ultimately be ruled safe to fly.
The company has completed several test flights of the 787 after doing so was approved by the FAA.