Well, there have been at least 100 of them replaced so far, for either being discharged too far, expired, or had charging problems. Apparently, it's pretty easy

Well, there have been at least 100 of them replaced so far, for either being discharged too far, expired, or had charging problems. Apparently, it's pretty easy for ground crews to leave something going that drains the battery to the point where it needs to be sent back to the manufacturer. That's on 50 planes that have been flying in commercial service for less than a year. Oh yeah, and that fire thing too.