AD 2018-10-10 Airworthiness Directives; Diamond Aircraft Industries GmbH Airplanes

Makes named: diamond, technify. Models named: DA 42. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to Diamond Aircraft Industries GmbH Model DA 42 airplanes, serial numbers 42.004 through 42.427 and 42.AC001 through 42.AC151, certificated in any category, that have either a TAE 125-02-99 or TAE 125-02-114 engine installed, and: (1) are equipped with an original engine exhaust pipe, Diamond Aircraft Industries (DAI) part number (P/N) D60-9078-06-01 or Technify P/Ns 52-7810-H0001 02, 52-7810-H0001 03, 52-7810-H0001 04; or (2) are equipped with a modified engine exhaust pipe DAI P/N D60-9078-06-01_01 or Technify 52-7810-H0014 01.

Unless already done, do the following actions. (1) An airplane is only required to have the actions of either (g) or (h) of this AD accomplished depending on the configuration. (2) For the purpose of this AD, if the flight hours accumulated since first installation of an affected exhaust pipe or additional exhaust pipe clamp is not known, use the total hours time-in-service (TIS) accumulated on the airplane.

See Appendix 1 to AD 2018-10-10 for a chart of required actions. An original engine exhaust pipe is defined in paragraph (c), Applicability, of this AD. (1) At the applicable compliance time in paragraphs (g)(1)(i) and (ii) of this AD, and repetitively thereafter at intervals not to exceed 500 hours time-in-service (TIS), inspect the installed engine exhaust pipe. Do this inspection following section III.4—Inspection of exhaust pipe in the INSTRUCTIONS section of DAI Work Instruction WI-MSB 42-120, Revision 4, dated December 20, 2017. (i) If the engine exhaust pipe has 1,300 hours TIS or less since first installed on an airplane as of June 12, 2018 (the effective date of this AD): Before or upon accumulating 1,500 hours TIS since the engine exhaust pipe was first installed on an airplane, and repetitively thereafter at intervals not to exceed 500 hours TIS. (ii) If the engine exhaust pipe has more than 1,300 hours TIS since first installed on an airplane as of June 12, 2018 (the effective date of this AD): Within the next 200 hours TIS after June 12, 2018 (the effective date of this AD), and repetitively thereafter at intervals not to exceed 500 hours time-in-service (TIS). (2) During any inspection required in paragraph (g)(1) of this AD, if the engine exhaust pipe does not pass the inspection criteria, before further flight replace the engine exhaust pipe following section III.1—Re-installation of Exhaust Pipes with Directly Attached Heat Shield in the INSTRUCTIONS section of DAI Work Instruction WI-OSB 42-131, dated December 20, 2017 (which includes installing additional engine exhaust pipe clamps, an exhaust sheet, and incorporates spring washers). After replacement continue with the 500-hour TIS repetitive inspections. (i) If only the engine exhaust pipe heat shield is loose, a one-time single weld is allowed following section III.3—Repair of Heat Shields of DAI P/N D60-9078-06-01/Technify P/Ns 52-7810-H0001 03 and 52-7810-H0001 04 in the INSTRUCTIONS section of DAI Work Instruction WI-OSB 42-131, dated December 20, 2017. After a repair of the heat shield, if a single weld point is subsequently found cracked, the heat shield is considered to be loose and the exhaust pipe must be replaced. After replacement or repair, continue with the 500-hour TIS repetitive inspections. (ii) Engine exhaust pipes re-qualified following section III.2—Re-Qualification of Exhaust Pipes DAI P/N D60-9078-06-01/Technify P/Ns 52-7810-H0001 02, 52-7810-H0001 03, or 52-7810-H0001 04 in the INSTRUCTIONS section of DAI Work Instruction WI-OSB 42-131, dated December 20, 2017, are considered to have accumulated 1,500 hours TIS. (3) Before further flight after the initial inspection required in paragraph (g)(1) of this AD and if no cracks were found or a repair to the exhaust pipe heat shield was done as required in paragraph (g)(2)(i) of this AD, then install additional engine exhaust pipe clamps, DAI P/Ns D60-7806-00-01 and D60-7806-00-02, and exhaust sheet, P/N D60-7806-00-03, and incorporate spring washers. Do the installations following III.2 Action 2—installation of additional exhaust clamp in the INSTRUCTIONS section of DAI Work Instruction WI-MSB 42-120, Revision 3, dated July 6, 2017, or Revision 4, dated December 20, 2017. See figure 1 to paragraph (g)(3) of this AD for additional information on the sequence of installation actions as identified in DAI Work Instruction WI-MSB 42-120, Revision 3, dated July 6, 2017 and Revision 4, dated December 20, 2017. ER23MY18.000 (4) During any engine exhaust pipe clamp and exhaust sheet with spring washer installation/replacement required in paragraphs (g)(2), (3), (6), and (7) of this AD, if the exhaust clamp assembly cannot be installed without side force using step 10 of III.2 Action 2—installation of additional exhaust clamp in the INSTRUCTIONS section of DAI Work Instruction WI-MSB 42-120, Revision 3, dated July 6, 2017, or Revision 4, dated December 20, 2017, before further flight contact the FAA at the address specified in paragraph (i) of this AD to obtain and incorporate an FAA-approved repair/modification approved specifically for this AD. The FAA will coordinate with the European Aviation Safety Agency (EASA) and DAI for the development of a repair/modification to address the specific problem. (5) At the applicable compliance time in paragraphs (g)(5)(i) and (ii) of this AD and repetitively thereafter at intervals not to exceed 25 hours TIS, remove and inspect each engine exhaust clamp for cracks. Do this inspection following III.3 Action 3—Inspection of exhaust clamp for cracks of the INSTRUCTIONS section of DAI Work Instruction WI-MSB 42-120, Revision 3, dated July 6, 2017, or Revision 4, dated December 20, 2017. (i) If the engine exhaust pipe clamp has less than 40 hours TIS since first installed on an airplane as of June 12, 2018 (the effective date of this AD): Before or upon accumulating 50 hours TIS since the engine exhaust pipe clamp was first installed on an airplane. (ii) If the engine exhaust pipe clamp has 40 hours TIS or more since first installed on an airplane as of June 12, 2018 (the effective date of this AD): Within the next 10 hours TIS after June 12, 2018 (the effective date of this AD). (6) Before further flight after any inspection required in paragraph (g)(5) of this AD and no crack is found, reinstall the engine exhaust pipe clamp, and incorporate spring washers following III.2 Action 2—installation of additional exhaust clamp in the INSTRUCTIONS section of DAI Work Instruction WI-MSB 42-120, Revision 3, dated July 6, 2017, or Revision 4, dated December 20, 2017. See figure 1 to paragraph (g)(3) of this AD for additional information on the sequence of installation actions as identified in DAI Work Instruction WI-MSB 42-120, Revision 3, dated July 6, 2017, and or Revision 4, dated December 20, 2017. Continue with the 25-hour TIS repetitive inspection as long as no cracks are found. (7) Before further flight after any inspection required in paragraph (g)(5) of this AD and a cracked engine exhaust pipe clamp is found, replace the cracked engine exhaust pipe clamp with a new engine exhaust pipe clamp and incorporate spring washers following the service instructions specified in paragraph (g)(6) of this AD. All newly installed engine exhaust pipe clamps are subject to an initial 50-hour TIS and repetitive 25-hour TIS inspections for cracks following the service instructions specified in paragraph (g)(5) of this AD.

This AD was prompted by mandatory continuing airworthiness information (MCAI) issued by the aviation authority of another country to identify and address an unsafe condition on an aviation product. It has been determined that installation of additional exhaust pipe brackets, combined with additional inspections, is the most adequate solution to address the original unsafe condition, while it was also established that the modified exhaust pipes without directly attached heat shield are not adequate as replacement parts. Durability analysis of the design is still under investigation and further improvements in the exhaust design are expected. For these reasons, this AD removes the option to install a modified exhaust pipe without direct heat shield, adds inspection requirements for airplanes modified in accordance with Section III.2 of Diamond Aircraft Industries (DAI) WI-MSB 42-120 Revision 3, dated July 6, 2017 (installation of additional brackets), and for airplanes on which an exhaust pipe with directly attached heat shield was re-installed in accordance with DAI Work Instruction WI-OSB 42-131, dated December 20, 2017. The MCAI describes the unsafe condition as uncommanded engine shutdown during flight due to failure of the propeller regulating valve caused by hot exhaust gases coming from fractured engine exhaust pipes. We are issuing this AD to prevent failure of the propeller regulating valve, which could result in forced landing, consequent damage and occupant injury.

This AD replaces 2017-01-12, Amendment 39-18779 (82 FR 5359, January 18, 2017) (“AD 2017-01-12”); AD 2017-11-08, Amendment 39-18907 (82 FR 24843, May 31, 2017) (“AD 2017-11-08”), and AD 2017-15-09, Amendment 39-18969 (82 FR 35630, August 1, 2017) (“AD 2017-15-09”).