AD 2019-22-11 Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

Models named: DHC-8-400, -401, -402. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Model DHC-8-400, -401, and -402 airplanes, certificated in any category, serial numbers 4001, 4003, and subsequent, equipped with main landing gear (MLG) forward stabilizer brace part number (P/N) 46401-7.

Comply with this AD within the compliance times specified, unless already done.

This paragraph restates the requirements of paragraph (f) of AD 2009-09-02, with new service information and removed reporting requirement. Unless already done, do the following actions: (1) At the applicable time specified in one of paragraphs (g)(1)(i) through (iv) of this AD: Perform non-destructive inspections for damage of the MLG forward stabilizer brace assemblies P/N 46401-7, in accordance with Bombardier Repair Drawing 8/4-32-099, Issue 1, dated March 10, 2009, and Goodrich Service Concession Request 026-09, Revision B, dated March 10, 2009; or Bombardier Repair Drawing 8/4-32-099, Issue 4, dated September 4, 2018, and UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018. Repeat the inspection thereafter at intervals not to exceed 2,000 flight cycles. As of the effective date of this AD, use Bombardier Repair Drawing 8/4-32-099, Issue 4, dated September 4, 2018, and UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018, for the actions required by this paragraph. (i) For airplanes with MLG forward stabilizer braces that have accumulated 12,000 or more total flight cycles as of May 6, 2009 (the effective date of AD 2009-09-02): Inspect within 50 flight cycles after May 6, 2009. (ii) For airplanes with MLG forward stabilizer braces that have accumulated 9,000 or more total flight cycles but fewer than 12,000 total flight cycles as of May 6, 2009 (the effective date of AD 2009-09-02): Inspect before the accumulation of 12,050 total flight cycles, or within 500 flight cycles after May 6, 2009, whichever occurs earlier. (iii) For airplanes with MLG forward stabilizer braces that have accumulated 4,500 or more total flight cycles but fewer than 9,000 total flight cycles as of May 6, 2009 (the effective date of AD 2009-09-02): Inspect before the accumulation of 9,500 total flight cycles, or within 1,500 flight cycles after May 6, 2009, whichever occurs earlier. (iv) For airplanes with MLG forward stabilizer braces that have accumulated fewer than 4,500 total flight cycles as of May 6, 2009 (the effective date of AD 2009-09-02): Inspect before the accumulation of 6,000 total flight cycles. (2) If any damage is found during any inspection required by paragraph (g)(1) of this AD, before further flight, do all applicable corrective actions in accordance with Goodrich Service Concession Request 026-09, Revision B, dated March 10, 2009; or UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018; except as provided by paragraphs (g)(3) through (6) of this AD. As of the effective date of this AD, use UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018, for the actions required by this paragraph. (3) For airplanes on which step 24. of Goodrich Service Concession Request 026-09, Revision B, dated March 10, 2009, has been done: Within 1,200 flight cycles after May 6, 2009 (the effective date of AD 2009- 09-02), rework the MLG forward stabilizer brace, and except for airplanes on which the rework has been done, within 600 flight cycles after May 6, 2009, do a detailed visual inspection for damage of the stabilizer brace apex lugs, in accordance with Goodrich Service Concession Request 026-09, Revision B, dated March 10, 2009; or UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018. If any damage is found, repair before further flight in accordance with Section C of Goodrich Service Concession Request 026-09, Revision B, dated March 10, 2009; or Section C of UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018. As of the effective date of this AD, use UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018, for the actions required by this paragraph. (4) At the applicable time specified in one of paragraphs (g)(4)(i) through (iii) of this AD, replace the forward stabilizer brace assembly, in accordance with Goodrich Service Concession Request 026-09, Revision B, dated March 10, 2009; or UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018. As of the effective date of this AD, use UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018, for the actions required by this paragraph. (i) For airplanes on which cracking is found during any inspection required by this AD, and the cracking exceeds the limit specified in paragraph (g)(4)(i)(A) or (B) of this AD, as applicable: Replace the assembly before further flight. (A) For cracking found before the effective date of this AD: The limit specified in Section C of Goodrich Service Concession Request 026-09, Revision B, dated March 10, 2009. (B) For cracking found on or after the effective date of this AD: The limit specified in Section C or Section D of UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018. (ii) For airplanes on which any cracking is found after the rework specified in Section C of Goodrich Service Concession Request 026-09, Revision B, dated March 10, 2009; or specified in Section C or Section D of UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018: Replace the assembly before further flight. (iii) For airplanes on which no cracking is found after the rework specified in Section C of Goodrich Service Concession Request 026-09, Revision B, dated March 10, 2009; or specified in Section C or Section D of UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018: Replace the assembly within 2,700 flight cycles after doing the rework. (5) If foreign object damage is found during any inspection required by this AD, or if damage is found to a forward stabilizer brace lug or stop bracket retention hole apex bushing, before further flight, repair using a method approved by the Manager, New York ACO Branch, FAA; or Transport Canada Civil Aviation (TCCA); or Bombardier, Inc.'s TCCA Design Approval Organization (DAO); or De Havilland Aircraft of Canada Limited's TCCA DAO. If approved by the DAO, the approval must include the DAO-authorized signature. (6) If any crack is found during the visual inspection under 10X magnification, repair before further flight, in accordance with Goodrich Service Concession Request 026-09, Revision B, dated March 10, 2009; or UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018. As of the effective date of this AD, use UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018, for the actions required by this paragraph. (7) Before the accumulation of 6,000 total flight cycles on the MLG forward stabilizer braces, or within 600 flight hours after May 6, 2009 (the effective date of AD 2009-09-02), whichever occurs later: Do a detailed visual inspection for cracking of both MLG forward stabilizer braces and do all applicable liquid penetrant inspections for cracking, in accordance with Bombardier Q400 All Operator Message 338, dated February 23, 2009. Repeat the inspection thereafter at intervals not to exceed 600 flight hours. If any cracking is found during any inspection required by this paragraph, repair before further flight in accordance with Bombardier Repair Drawing 8/4-32-099, Issue 1, dated March 10, 2009, and Goodrich Service Concession Request 026-09, Revision B, dated March 10, 2009; or Bombardier Repair Drawing 8/4-32-099, Issue 4, dated September 4, 2018, and UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018. As of the effective date of this AD, use Bombardier Repair Drawing 8/4-32-099, Issue 4, dated September 4, 2018, and UTC Aerospace Systems Service Concession Request 026-09, Revision H, dated August 29, 2018, to repair cracking found during any inspection required by this paragraph.

This AD was prompted by reports of failures of the aft hinge of the MLG forward stabilizer brace due to fatigue cracks. The FAA is issuing this AD to address failure of the stabilizer brace, which could result in the collapse of the MLG.

This AD replaces AD 2009-09-02, Amendment 39-15888 (74 FR 18121, April 21, 2009) (“AD 2009-09-02”).