FAA supersedes existing airworthiness directive for 787-8 aircraft

US FAA announced it is superseding (26-Apr-2013) an existing airworthiness directive for Boeing 787-8 aircraft. The existing airworthiness directive requires modification of the battery system, or other actions. The new directive requires installing main and auxiliary power unit (APU) battery enclosures and environmental control system (ECS) ducts; and replacing the main battery, APU battery, and their respective battery chargers. It also requires revising the maintenance programme to include an
airworthiness limitation. The airworthiness directive also revises the applicability by removing aircraft on which these changes have been incorporated in production prior to delivery. The directive was prompted by recent incidents involving lithium ion battery failures that resulted in release of flammable electrolytes, heat damage, and smoke on two 787-8 aircraft. The FAA is issuing this directive to minimise the occurrence of battery cell failures and propagation of such failures to other cells and to contain any flammable electrolytes, heat, and smoke released during a battery thermal event in order to prevent damage to critical systems and structures and the potential for fire in the electronics equipment bays. It is effective 26-Apr-2013. It is estimated to affect six aircraft of US registry, at a cost to US operators of USD2.8 million (USD465,000 per aircraft). [more - original PR]