My comment on the Boeing engineers was regarding their use of electrical power for some functions instead of bleed air. The battery problems appear to be related to Lithium Ion batteries. The discrepant batteries are being investigated now to see if they were manufactured in the same lot, had similar discrepancies, etc. Boeing's contention is that we have over one million flight hours on that type battery with no issues. Lots of hard work, investigation and probably some engineering to do before this is resolved. More to come.
Regards,
Gus