Airworthiness Directives; JanAero Devices B-Series Combustion Heaters, Models B1500, B2030, B3040, and B4050 (formerly owned by Janitrol, C&D, FL Aerospace, and Midland-Ross Corporation)

This amendment supersedes Airworthiness Directive (AD) 82-07- 03, which currently requires repetitively testing (pressure decay) the combustion tube of JanAero Devices B-Series combustion heaters, Models B1500, B2030, B3040, and B4050, that are installed on aircraft, and overhauling any heater that does not pass one of these pressure decay tests. This action retains the pressure decay test and possible heater overhaul requirements of AD 82-07-03; and requires repetitive operational testing of the combustion air pressure switch, and replacing any combustion pressure switch that does not pass one of these tests. Two occurrences of failure of the affected heaters prompted this action. In one case, an explosion resulted and the baggage compartment door was blown off the airplane. In the other case, a fire occurred in the baggage compartment while the airplane was in flight. The actions specified by this AD are intended to prevent an airplane fire or explosion caused by failure of the heater combustion tube assembly or combustion air pressure switch.