Airworthiness Directive · Amendment 39-18827 · Heating system
Meggitt (Troy), Inc. Combustion Heaters
(1) This AD applies to Meggitt (Troy), Inc. (previously known as Stewart Warner South Wind Corporation and as Stewart Warner South Wind Division) Models (to include all dash number and model number variants) 921, 930, 937, 940, 944, 945, 977, 978, 979, 8240, 8253, 8259, and 8472 combustion heaters that:
(i) Are installed on, but not limited to, certain Beech, Britten-Norman, Cessna Aircraft Company, and Piper Aircraft, Inc. airplanes; and
(ii) certificated in any category.
We are superseding Airworthiness Directive (AD) 81-09-09 for certain Meggitt (Troy), Inc. (previously known as Stewart Warner South Wind Corporation and as Stewart Warner South Wind Division) Model Series (to include all the variants) 921, 930, 937, 940, 944, 945, 977, 978, 979, 8240, 8253, 8259, and 8472 combustion heaters. AD 81-09-09 required repetitive inspections of the combustion heater; repetitive installation inspections of the combustion heater; and, for combustion heaters having 1,000 hours or more time-in-service (TIS), overhaul of the combustion heater. This new AD requires detailed repetitive inspections, repetitive pressure decay tests, and disable/removal of the combustion heater if necessary. This AD was prompted by an airplane accident and reports that the heater was malfunctioning. We are issuing this AD to correct the unsafe condition on these products.
Comply with this AD by doing one of the actions in paragraphs (f)(1), (2), or (3) of this AD at the compliance times indicated, unless already done. If the hours of combustion heater operation cannot be determined, use 50 percent of the airplane's hours time-in-service (TIS):
(1) Perform the actions specified in paragraphs (g) through (j) of this AD;
(2) Disable the heater following the instructions in paragraph (k)(1) of this AD; or
(3) Remove the heater following the instructions in paragraph (k)(2) of this AD.
Within the next 10 hours TIS of the combustion heater after May 5, 2017 (the effective date of this AD) or the next scheduled 100-hour inspection, annual inspection, or phase inspection that occurs 30 days after May 5, 2017 (the effective date of this AD), whichever occurs first, and repetitively thereafter at intervals not to exceed 250 hours of combustion heater operation or two years, whichever occurs first, do the following inspections and PDT listed in paragraphs (g)(1) through (4) of this AD. You may do one of the actions in paragraph (k)(1) or (2) of this AD in lieu of doing the inspections required by paragraph (g).
(1) Inspections using the instructions in paragraph (i)(1) or (j) of this AD, as applicable.
(2) Inspections using the steps listed in paragraphs (g)(2)(i) through (v) of this AD:
(i) Inspect the thermostat switch (external from heater) and upper limit switch (located on the heater). In cold static condition, both switches should be in closed position; in operation (hot) condition, both switches should regulate their sensed temperatures within ± 10 degrees F.
(ii) Inspect the solenoid valve and fuel pump for fuel leak, corrosion, diaphragm crack, metal shavings, and excess grease.
(iii) With the heater operating, inspect the fuel pump output pressure for proper gauge hook up and pressure range readings.
(iv) Inspect the combustion heater's fuel pump operating pressure to assure it is not affected by other on-board pumps.
(v) Inspect the heater to assure it instantly responds to the on/off switch.
(3) Installation inspections and checks using the steps listed in paragraphs (g)(3)(i) through (iv) of this AD:
(i) Inspect ventilating air and combustion air inlets and exhaust outlet correcting any restrictions and ensure attachment security.
(ii) Inspect drain line and ensure it is free of obstruction.
(iii) Check all fuel lines for security at joints and shrouds, correcting/replacing those showing evidence of looseness or leakage.
(iv) Check all electrical wiring for security at attachment points, correcting conditions leading to arcing, chafing or looseness.
(4) Pressure decay test using the instructions in paragraph (i)(2) or (j) of this AD, as applicable.
If any discrepancies are found during any of the inspections/PDTs required in paragraphs (g)(1), (2), (3), and/or (4) of this AD, before further flight, replace the defective heater tube and/or correct or replace other defective assemblies as necessary. You must use the instructions in paragraph (i) or (j) of this AD, as applicable, to do any necessary replacements. This AD does not allow repair of the combustion tube. You may do one of the actions in paragraph (k)(1) or (2) of this AD in lieu of doing the replacements required by paragraph (h).
(1) For the inspections required in paragraph (g)(1) of this AD and the replacement(s) that may be required in paragraph (h) of this AD, use the service information listed in paragraphs (i)(1)(i) through (iii) of this AD, as applicable, or do one of the actions in paragraph (k)(1) or (2) of this AD.
(i) Stewart-Warner South Wind Corporation South Wind Service Manual for Stewart Warner South Wind Aircraft Heaters 8240-A, 8240-C, 8259-A, 8259-C, 8259-DL, 8259-FL1, 8259-GL1, 8259-GL2, Form No. 09-998, revised: December 1969;
(ii) South Wind Division Stewart-Warner Corporation Beech Aircraft Corporation Service Manual PM-20688, Part No. 404-001039 Heater Assy. (SW 8253-B), Part No. 404-001056 Blower Assy. (SW G-716307), Part No. G-714127 Thermostat (SW G-714127), revised: April 1965; or
(iii) South Wind Division Stewart-Warner Corporation Service Manual South Wind Aircraft Heater 8472 Series, Form No. 09-1015, issued: April 1975.
(2) For the PDT required in paragraph (g)(4) of this AD, use Meggitt Inspection Procedure, Pressure Decay Test, Aircraft Heaters, IP-347, dated May 17, 2014, or do one of the actions in paragraph (k)(1) or (2) of this AD.
This AD does not have referenced service information associated with the mandatory requirements of this AD for models other than Models 8240, 8253, 8259, and 8472. For the required inspections and PDT specified in paragraphs (g)(1) and (4) of this AD and, if necessary, any replacement(s) specified in paragraph (h) of this AD, you must contact the manufacturer to obtain FAA-approved inspection, replacement, and PDT procedures approved specifically for this AD and implement those procedures through an alternative method of compliance (AMOC) or do one of the actions in paragraph (k)(1) or (2) of this AD. You may use the contact information found in paragraph (n)(2) to contact the manufacturer. Appendix 1 of this AD contains a listing of service information that provides specific instructions, for certain inspections and replacements, that you may use to apply for an AMOC following paragraph (m) of this AD. The service information listed in appendix 1 of this AD did not meet Office of the Federal Register regulatory requirements for incorporation by reference approval due to the condition of the documents. However, the listing in appendix 1 to this AD does not include any instructions for the PDT required in paragraph (g)(4) because these procedures do not exist.
As an option to the inspection, PDT, and replacement actions specified in paragraphs (g) and (h) of this AD, within the next 10 hours TIS of the combustion heater after the effective date of this AD or the next scheduled 100-hour inspection, annual inspection, or phase inspection that occurs 30 days after the effective date of this AD, whichever occurs first, do one of the following actions:
(1) Disable the heater by the following actions:
(i) Disconnect and cap the heater fuel supply.
(ii) Disconnect circuit breakers.
(iii) Tag the main switch “Heater Inoperable.”
(iv) The ventilation blower can stay functional.
(v) If you re-enable the combustion heater, before further flight, you must perform the actions in paragraphs (f)(1) of this AD. If you cannot complete the actions of paragraph (f)(1) satisfactorily, you must perform the actions in either paragraph (f)(2) or (3) of this AD.
(2) Remove the heater by the following actions:
(i) Disconnect and cap the heater fuel supply.
(ii) Disconnect/remove circuit breakers.
(iii) Remove exhaust pipe extension;.
(iv) Cap the exhaust opening.
(v) Remove the heater.
(vi) Do weight and balance for the aircraft.
(vii) If you install an applicable combustion heater on the airplane, before further flight, you must perform the actions in paragraphs (f)(1) of this AD. If you cannot complete the actions of paragraph (f)(1) satisfactorily, you must perform the actions in either paragraph (f)(2) or (3) of this AD.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Appliances and equipment
