IMO for a definitive answer you'll need to talk to Yuasa. I know SOME lead acid batteries are approved. They need to be Dry Cell and should have a legend on the battery that goes something like "FAA, CAB, ICAO, IMDG, and IATA and DOT Air Transport Approved". Here is an example of a compliant battery. If yours isn't, it's quite cheap to get a new one that is.