Airworthiness Directive · Amendment 39-19917 · Nacelles/pylons
July 14, 2020 Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes
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 and subsequent.
The FAA is superseding Airworthiness Directive (AD) 2010-23- 04, which applied to all De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. AD 2010-23-04 required repetitive detailed inspections of the nacelle attachment fittings for cracks, a conductivity inspection of the nacelle attachment fittings, and replacement if necessary. This AD continues to require these inspections and replacement if necessary, removes a certain inspection requirement for certain airplanes, and adds a new requirement to replace the rear spar fitting and nacelle attaching structure with a new nacelle attachment fitting. This AD was prompted by a determination that it is necessary to do a replacement with new nacelle attachment fittings. The FAA is issuing this AD to address the unsafe condition on these products.
This paragraph restates the requirements of paragraph (g) of AD 2010-23-04, with revised service information and revised replacement instructions. For airplanes having serial numbers 4001 through 4304 inclusive, 4314, and 4315: Within 100 flight hours after November 22, 2010 (the effective date of AD 2010-23-04), do a detailed inspection for cracking, and a conductivity inspection on each of the 4 nacelle attachment fittings, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 84-54-14, Revision K, dated August 7, 2018. Repeat the detailed inspection at intervals not to exceed 300 flight hours, except as provided by paragraph (i) of this AD. Accomplishing the replacement specified in paragraph (g)(1)(ii) or (g)(2)(ii)(B) of this AD terminates the inspections required by this paragraph.
(1) If any nacelle attachment fitting is found cracked, before further flight, do the action specified in paragraph (g)(1)(i) or (ii) of this AD. As of the effective date of this AD, only the action specified in paragraph (g)(1)(ii) of this AD may be done.
(i) Replace the fitting with a new fitting in accordance with paragraph (2) of Part A of the Accomplishment Instructions of Bombardier Service Bulletin 84-54-14, Revision K, dated August 7, 2018.
(ii) Replace the rear spar nacelle attachment fitting and associated structure with a new nacelle attachment fitting, part number (P/N) 8Z9305, and do all applicable related investigative and corrective actions, in accordance with Part B of the Accomplishment Instructions of Bombardier Service Bulletin 84-54-16 Revision D, dated August 7, 2018. Do all applicable related investigative and corrective actions before further flight.
(2) If the conductivity of any test points on any fitting is found to be greater than 45.0 percent International Annealed Copper Standard (IACS) or if the conductivity of any test points on any fitting is found to be less than 38.0 percent IACS, do the actions required by paragraphs (g)(2)(i) and (ii) of this AD.
(i) Within 24 hours after accomplishing the conductivity inspection specified in paragraph (g) of this AD, do a detailed inspection of the nacelle attachment fitting for cracking, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 84-54-14, Revision K, dated August 7, 2018, and repeat thereafter at intervals not to exceed 24 hours. If cracking is found, before further flight, replace the fitting with a new fitting in accordance with the requirements of paragraph (g)(2)(ii) of this AD. Replacement of the fitting terminates the daily detailed inspection requirements of this paragraph.
(ii) Except as required by paragraph (g)(2)(i) of this AD: Within 300 flight hours after accomplishing the conductivity inspection specified in paragraph (g) of this AD, do the action specified in paragraph (g)(2)(ii)(A) or (B) of this AD. As of the effective date of this AD, only the action specified in paragraph (g)(2)(ii)(B) of this AD may be done.
(A) Replace the fitting with a new fitting in accordance with paragraph (2) of Part A of the Accomplishment Instructions of Bombardier Service Bulletin 84-54-14, Revision K, dated August 7, 2018.
(B) Replace the rear spar nacelle attachment fitting and associated structure with a new nacelle attachment fitting, P/N 8Z9305, and do all applicable related investigative and corrective actions, in accordance with Part B of the Accomplishment Instructions of Bombardier Service Bulletin 84-54-16 Revision D, dated August 7, 2018. Do all applicable related investigative and corrective actions before further flight.
This paragraph restates the requirements of paragraph (i) of AD 2010-23-04, with revised service information, revised affected airplanes, and revised replacement instructions. For airplanes having serial numbers 4305 through 4313 inclusive, and 4316 through 4380 inclusive, and airplanes that have replaced nacelle attachment fitting(s) with P/N 854146663: Within 1,200 flight hours after November 22, 2010 (the effective date of AD 2010-23-04), do a detailed inspection for cracking on each of the 4 nacelle attachment fittings, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 84-54-14, Revision K, dated August 7, 2018. If any nacelle attachment fitting is found cracked, before further flight, do the action specified in paragraph (h)(1) or (2) of this AD. As of the effective date of this AD, only the action specified in paragraph (h)(2) of this AD may be done. Thereafter, repeat the detailed inspection at intervals not to exceed 300 flight hours, except as provided by paragraph (i) of this AD. Accomplishing the replacement specified in paragraph (h)(2) of this AD terminates the inspections required by this paragraph.
(1) Replace the fitting with a new fitting in accordance with paragraph (2) of Part A of the Accomplishment Instructions of Bombardier Service Bulletin 84-54-14, Revision K, dated August 7, 2018.
(2) Replace the rear spar nacelle attachment fitting and associated structure with a new nacelle attachment fitting, P/N 8Z9305, and do all applicable related investigative and corrective actions, in accordance with Part B of the Accomplishment Instructions of Bombardier Service Bulletin 84-54-16 Revision D, dated August 7, 2018. Do all applicable related investigative and corrective actions before further flight.
This paragraph restates the requirements of paragraph (j) of AD 2010-23-04, with revised service information. For any fitting that is replaced in accordance with paragraph (3) of Part A of the Accomplishment Instructions of Bombardier Service Bulletin 84-54-14, Revision J, dated September 17, 2010; or paragraph (2) of Part A of the Accomplishment Instructions of Bombardier Service Bulletin 84-54-14, Revision K, dated August 7, 2018, as specified in paragraph (g) or (h) of this AD: Within 1,200 flight hours after replacing the fitting, do a detailed inspection of that replaced fitting as specified in paragraph (g) or (h) of this AD, and repeat the detailed inspection thereafter at intervals not to exceed 300 flight hours. Accomplishing the replacement specified in paragraph (g)(1)(ii), (g)(2)(ii)(B), or (h)(2) of this AD terminates the inspections required by this paragraph.
This paragraph restates the credit provided in paragraph (k) of AD 2010-23-04, with revised paragraph references. Accomplishing the replacement of the nacelle fittings in accordance with any Bombardier service bulletin identified in figure 1 to paragraphs (j) and (k) of this AD before November 22, 2010 (the effective date of AD 2010-23-04) is also acceptable for compliance with the fitting replacements specified in paragraphs (g)(1)(i), (g)(2)(ii)(A), and (h)(1) of this AD.
This paragraph restates the credit provided in paragraph (l) of AD 2010-23-04, with no changes. Accomplishment of the inspections required by paragraphs (g) and (h) of this AD before November 22, 2010 (the effective date of AD 2010-23-04) in accordance with any Bombardier service bulletin identified in figure 1 to paragraphs (j) and (k) of this AD is acceptable for compliance with the corresponding actions required by paragraphs (g) and (h) of this AD.
For airplanes with nacelle attachment fitting P/N 85414663: Unless already done as specified in paragraph (g)(1)(ii), (g)(2)(ii)(B), or (h)(2) of this AD: Within 8,000 flight hours or 48 months, whichever occurs first, from the effective date of this AD, replace the rear spar nacelle attachment fitting and associated structure with a new nacelle attachment fitting, P/N 8Z9305, and do all applicable related investigative and corrective actions, in accordance with Part B of the Accomplishment Instructions of Bombardier Service Bulletin 84-54-16, Revision D, dated August 7, 2018. Do all applicable related investigative and corrective actions before further flight.
(1) This paragraph provides credit for actions required by paragraphs (g) and (h) of this AD that are identified in Bombardier Service Bulletin 84-54-14, Revision K, dated August 7, 2018, if those actions were performed before the effective date of this AD using Bombardier Service Bulletin 84-54-14, Revision J, dated September 17, 2010, which was incorporated by reference in AD 2010-23-04; except as provided by paragraph (p) of this AD.
(2) This paragraph provides credit for accomplishing the replacement of the rear spar fitting and nacelle attaching structure required by paragraph (l) of this AD, if those actions were performed before the effective date of this AD using the service information specified in paragraphs (m)(2)(i) through (iii) of this AD.
(i) Bombardier Service Bulletin 84-54-16, dated April 29, 2011.
(ii) Bombardier Service Bulletin 84-54-16, Revision A, dated August 1, 2011.
(iii) Bombardier Service Bulletin 84-54-16, Revision C, dated January 31, 2017.
(3) This paragraph provides credit for accomplishing the replacement of the rear spar fitting and nacelle attaching structure required by paragraph (l) of this AD, if those actions were performed before the effective date of this AD using Bombardier Service Bulletin 84-54-16, Revision B, dated October 6, 2016. Although Bombardier Service
Bulletin 84-54-16, Revision B, dated October 6, 2016, incorrectly stated that airworthiness limitations (AWLs) or damage tolerance inspections (DTIs) are not affected, they are affected. Refer to the applicable AWLs for Post/Pre-Modification Summary (ModSum) 4-113697 and Bombardier Service Bulletin 84-54-16 in the existing maintenance requirements manual.
(4) This paragraph provides credit for accomplishing the action identified in Bombardier Service Bulletin 84-54-14, Revision K, dated August 7, 2018, that are required by paragraphs (g) and (h) of this AD, if those actions were performed before the effective date of this AD using the service information specified in paragraphs (m)(4)(i) through (iv) of this AD.
(i) Bombardier Service Bulletin 84-54-15, dated August 20, 2010.
(ii) Bombardier Service Bulletin 84-54-15, Revision A, dated October 25, 2010. (iii) Bombardier Service Bulletin 84-54-15, Revision B, dated February 2, 2017. (iv) Bombardier Service Bulletin 84-54-15, Revision C, dated August 7, 2018.
Accomplishing the modification of the rear spar fitting and nacelle attaching structure required by paragraph (l) of this AD terminates the repetitive inspection required by paragraphs (g), (h), and (i) of this AD for that airplane.
As of the effective date of this AD, no person may install a rear spar nacelle attachment fitting P/N 85414663 on any airplane.
For airplanes on which Bombardier Service Bulletin 84-54-14, Revision J, dated September 17, 2010, was accomplished before the effective date of this AD: As an alternative to applying sealant to each fitting and access panel as specified in paragraph C.(1) of the Accomplishment Instructions of Bombardier Service Bulletin 84-54-14, Revision J, dated September 17, 2010, the use of the instructions of Bombardier Modification Summary Package IS4Q5400012, Revision B, dated July 11, 2012, to apply sealant is also acceptable if accomplished before the effective date of this AD.
