Summary
The FAA proposes to revise Airworthiness Directive (AD) 2004- 25-16, which applies to aircraft equipped with a fuel regulator shutoff valve part number (P/N) 14D11, A14D11, B14D11, C14D11, 23D04, A23D04, B23D04, C23D04, or P23D04 used with B1500, B2030, B2500, B3040, B3500, B4050, or B4500 B-Series combustion heaters. AD 2004-25-16 currently requires you to repetitively inspect the fuel regulator shut shutoff valve (visually or by pressure test) for fuel leakage and replace the fuel regulator shutoff valve with an improved design replacement part with a manufacturer's date code of 02/ 02 or later if fuel leakage is found. AD 2004-25-16 also allows you to disable the heater as an alternative method of compliance. Since we issued AD 2004-25-16, we received several comments requesting a revision to paragraph (e)(2). Consequently, this proposed AD retains the actions required in AD 2004-25-16 and revises the requirements in paragraph (e)(2) to remove a required action. We are issuing this proposed AD to prevent failure of the fuel regulator shutoff valve, which could result in fuel leakage in aircraft with these combustion heaters. This failure could result in an aircraft fire.