Tests of the revised Boeing 787 battery system are expected to be completed “within weeks” and will involve only a single flight test, says VP and 787 Chief Project Engineer Mike Sinnett.Revealing full design details of the revised lithium ion battery system, Sinnett also discloses that the enclosure system developed for the battery is designed to prevent a fire and not, as widely reported, to contain one. This fundamental fact, unknown until Boeing revealed details of the new system during a March 15 press conference in Tokyo, will be pivotal in the FAA’s coming assessment of whether the modified 787 can be allowed to return to unrestricted flight.The enclosure is one of several features of what Boeing calls a “comprehensive solution” to provide multiple layers of protection for the battery system. The battery itself is modified with additional spacers and insulation to improve the thermal and electrical isolation, added insulation layers, cells individually wrapped in electrical isolation tape and wire harnesses encased in heat and chafe resistant sleeves.