Safety chiefs call for checks on aircraft batteries returning to service after pandemic

Aviation safety chiefs are calling for nickel-cadmium (Ni-Cd) batteries used in aircraft to undergo airworthiness checks, before planes return to the skies after being grounded by Covid-19.

The European Union Aviation Safety Agency (EASA) has warned in a safety information bulletin (SIB) that Ni-Cd batteries that have been disconnected from aircraft for long periods, as a result of the pandemic, can self-discharge – reducing battery capacity.

The SIB said: “As aircraft batteries are the final power source available to aircraft, this reduction in capacity of the Ni-Cd batteries may not meet the minimum battery endurance certification requirements when the aircraft is operated again, which may lead to a premature total electrical power loss in the case the aircraft’s main electrical system fails.”

A reduction of capacity cannot be reversed by the normal aircraft charging system and the reduction in total capacity “cannot be detected without the battery being sent to an approved battery shop for a battery recharge check or overhaul”, the agency said.

EASA said the issue was “not considered to be a generic unsafe condition affecting multiple products”. However, the agency said it was “vital” that aircraft put into storage for weeks or months “are restored to an airworthy condition prior to the restart of operations”.

The agency is recommending that aircraft design approval holders, in conjunction with advice from battery manufacturers, “review their electrical system designs and their parking and storage instructions, to determine if the battery system can tolerate successive reconnection cycles” without suffering from the self-discharge phenomenon.