Airworthiness Directive · Amendment 39-19762 · Wings
De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes
This AD applies to De Havilland Aircraft of Canada Limited Model DHC-8-400, -401, and -402 airplanes, certificated in any category, serial numbers 4001 through 4437 inclusive.
The FAA is superseding Airworthiness Directive (AD) 2011-18- 15, which applied to certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. AD 2011-18-15 required initial and repetitive torque checks of the bolt preload; detailed inspection of the barrel nuts and cradle for cracking, pitting, and corrosion if the bolt preload is correct; and replacement of certain hardware if necessary. This AD continues to require those actions. This AD also requires new inspections and replacement of certain hardware, which would terminate the repetitive torque checks and inspections; and removes airplanes from the applicability. This AD was prompted by in- service reports of cracked barrel nuts found at the front spar locations of the wing-to-fuselage attachment joints, and a loose washer in the barrel nut assembly. The FAA is issuing this AD to address the unsafe condition on these products.
This paragraph restates the requirements of paragraph (g) of AD 2011-18-15, with revised service information. At the applicable time specified in paragraph (g)(1) or (2) of this AD: Do a torque check to determine if the bolt preload is correct, and if the preload is correct, before further flight, do a detailed inspection of each barrel nut and cradle for cracking, pitting or corrosion, in accordance with paragraph 3.B., part A, of the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-25, dated July 20, 2011; or Bombardier Service Bulletin A84-57-25, Revision A, dated July 16, 2018. After the effective date of this AD, only Bombardier Service Bulletin A84-57-25, Revision A, dated July 16, 2018, may be used. Repeat the torque check and, as applicable, the inspection thereafter at intervals not to exceed 2,000 flight hours or 12 months, whichever occurs first.
(1) For airplanes that have accumulated 1,900 or more total flight hours as of September 15, 2011 (the effective date of AD 2011-18-15), or for which it has been 12 months or more since the date of issuance of the original Canadian airworthiness certificate or the date of issuance of the original Canadian export certificate of airworthiness as of September 15, 2011: Within 100 flight hours or 10 days after September 15, 2011, whichever occurs first.
(2) For airplanes that have accumulated less than 1,900 total flight hours as of September 15, 2011 (the effective date of AD 2011-18-15), and for which it has been less than 12 months since the date of issuance of the original Canadian airworthiness certificate or the date of issuance of the original Canadian export certificate of airworthiness as of September 15, 2011: Prior to the accumulation of 2,000 total flight hours or within 12 months since the date of issuance of the original Canadian standard airworthiness certificate or the date of issuance of the original Canadian export certificate of airworthiness, whichever occurs first.
This paragraph restates the requirements of paragraph (h) of AD 2011-18-15, with revised service information. If any bolt preload is found to be incorrect (i.e., the ring can be rotated during any torque check required by paragraph (g) of this AD), before further flight, replace all hardware at that location (except the saddle washer and retainer) in accordance with paragraph 3.B., part B, of the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-25, dated July 20, 2011; or paragraph 3.B. of the Accomplishment Instructions of Bombardier Service Bulletin 84-57-26, Revision C, dated July 16, 2018. After the effective date of this AD, only Bombardier Service Bulletin 84-57-26, Revision C, dated July 16, 2018, may be used.
This paragraph restates the requirements of paragraph (i) of AD 2011-18-15, with revised service information. If any crack, pitting, or corrosion of the barrel nut or cradle is found during any inspection required by paragraph (g) of this AD, before further flight, replace all hardware at that location (except the saddle washer and retainer) in accordance with paragraph 3.B., part B, of the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-25, dated July 20, 2011; or paragraph 3.B. of the Accomplishment Instructions of Bombardier Service Bulletin 84-57-26, Revision C, dated July 16, 2018. After the effective date of this AD, only Bombardier Service Bulletin 84-57-26, Revision C, dated July 16, 2018, may be used.
Within 12,000 flight hours or 72 months after the effective date of this AD, whichever occurs first: Do a visual inspection of the saddle washer and retainer for any damage (cracks) or corrosion; and replace the wing front spar barrel nuts, bolts, and preload indicating washers; in accordance with paragraph 3.B. of the Accomplishment Instructions of Bombardier Service Bulletin 84-57-26, Revision C, dated July 16, 2018.
If any damage (cracks) or corrosion is found during any inspection required by paragraph (j) of this AD: Before further flight, accomplish corrective actions in accordance with the procedures specified in paragraph (p)(2) of this AD.
Accomplishment of the applicable actions required by paragraphs (j) and (k) of this AD, at all four barrel nut locations, terminates the repetitive torque checks and detailed inspections of paragraph (g) of this AD.
