65-07-01\tBOEING: Amdt. 39-51 Part 39 Federal Register April 1, 1965. Applies to Models 707 and 720 Series Aircraft. \n\n\tCompliance required as indicated. \n\n\tTo reduce the possibility of further fires in the cabin lower sidewall panels in the return air system, accomplish the following: \n\n\t(a)\tWithin 5,000 hours' time in service after March 20, 1964, install lower sidewall modifications, including flame-resistant insulation, fire-stop air baffles, and metal grills, in areas other than behind galleys and other equipment located flush against the cabin sidewall, in accordance with Boeing Service Bulletins Nos. 1807(R-1), 1807(R-1)A, 1861, and 1868, as applicable, or an FAA-approved equivalent.\n \n\t(b)\tWithin 6,000 hours' time in service after March 20, 1964, install lower sidewall modifications, including flame-resistant insulation, fire-stop air baffles, and metal grills, behind galleys and other equipment located flush against the cabin sidewall in accordance with Boeing Service Bulletins Nos. 1807(R-1), 1807(R-1)A, 1861, and 1868, as applicable, or an FAA- approved equivalent.\n \n\tThis supersedes AD 64-04-01. \n\n\tThis directive effective April 1, 1965.