AD 2004-21-05
Unsafe Condition
Failure of the combustion heater system, leading to combustion by-products (carbon-monoxide exhaust) and fuel leakage.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Repetitively inspect (pressure decay test) the combustion tube of the heater. Overhaul the heater and replace the combustion tube with a serviceable tube or replace the heater assembly if the heater fails any of these tests. Repetitively test the operation of the combustion air pressure switch. Replace the switch with one of the same design or with one of improved design, P/N 94E42, if the combustion air pressure switch fails any of these tests.
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Compliance Time
Within 50 flight hours after the effective date of this AD.
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Affected Aircraft
Kelly Aerospace Power Systems B-Series Combustion Heaters Models B1500, B2030, B2500, B3040, B3500, B4050, and B4500 (formerly owned by JanAero Devices, Janitrol, C&D, FL Aerospace, and Midland-Ross Corporation).
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
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