Airworthiness Directive · Amendment 39-15661 · Bombardier Model DHC-8-400 Series Airplanes
Bombardier Model DHC-8-400 Series Airplanes
This AD applies to Bombardier Model DHC-8-400, DHC-8-401, and DHC-8-402 airplanes, certificated in any category; serial numbers 4001 and 4003 through 4176 inclusive.
The FAA is superseding an existing airworthiness directive (AD), which applies to certain Bombardier Model DHC-8-400 series airplanes. That AD currently requires inspecting all barrel nuts to determine if the barrel nuts have a certain marking, inspecting affected bolts to determine if the bolts are pre-loaded correctly, and replacing all hardware if the pre-load is incorrect. For airplanes on which the pre-load is correct, the existing AD requires doing repetitive visual inspections for cracking of the barrel nuts and cradles and replacing all hardware for all cracked barrel nuts. The existing AD also requires replacing all hardware for certain affected barrel nuts that do not have cracking, which would end the repetitive inspections for those airplanes. The existing AD also provides an optional replacement for all affected barrel nuts. This new AD requires replacing all affected barrel nuts and applying a certain compound to the affected barrel nuts and bolts. This AD results from reports of cracking in the barrel nuts at the four primary front spar wing-to- fuselage attachment joints. We are issuing this AD to detect and correct cracking of the barrel nuts at the wing front spar wing-to- fuselage joints, which could result in reduced structural integrity of the wing-to-fuselage attachments and consequent detachment of the wing.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Within 50 flight hours after February 13, 2008 (the effective date of AD 2008-04-02), inspect all barrel nuts, part number DSC228-16, to determine if the barrel nuts are identified with a marking of LH7940T SPS 01. Inspect in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-19, Revision A, dated February 6, 2008; or Revision B, dated March 6, 2008. As of the effective date of this AD, Bombardier Alert Service Bulletin A84-57-19, Revision B, dated March 6, 2008, must be used.
(1) If no barrel nuts are identified with a marking of LH7940T SPS 01, no further actions are required by this paragraph.
(2) If any barrel nut is found that is identified with a marking of LH7940T SPS 01, before further flight, inspect the inboard and outboard bolts to determine if the bolts are pre-loaded correctly. Inspect in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-19, Revision A, dated February 6, 2008; or Revision B, dated March 6, 2008. As of the effective date of this AD, Bombardier Alert Service Bulletin A84-57-19, Revision B, dated March 6, 2008, must be used.
(i) If the pre-load is incorrect (i.e., the ring can be rotated), before further flight, replace all hardware at that location in accordance with the Accomplishment Instructions of the alert service bulletin.
(ii) If the pre-load is correct, before further flight, do a visual inspection for cracking of the barrel nuts and cradles in accordance with the Accomplishment Instructions of the alert service bulletin.
(A) If no cracking of the barrel nut and cradle is found, do the applicable action required by paragraph (g) of this AD.
(B) If no cracking of the barrel nut is found and only cracking of the cradle is found, no action is required by this paragraph provided that the applicable corrective action specified in paragraph (g) of this AD is done.
(C) If any cracking of the barrel nut is found, before next flight, replace all hardware only at that location in accordance with the Accomplishment Instructions of the alert service bulletin.
(g) For any barrel nuts on which no cracking of the barrel nut was found during the inspection required by paragraph (f)(2)(ii) of this AD, do the applicable corrective action specified in paragraph (g)(1), (g)(2), (g)(3), (g)(4), or (g)(5) of this AD at the compliance time specified in the applicable paragraph.
(1) If four barrel nuts having no cracking are found, do the actions specified in paragraphs (g)(1)(i), (g)(1)(ii), and (g)(1)(iii) of this AD.
(i) Within 50 flight hours after doing the inspection required by paragraph (f)(2)(ii) of this AD, repeat the inspection specified in paragraph (f)(2) of this AD. Thereafter, repeat the inspection at intervals not to exceed 50 flight hours until the replacement specified in paragraph (g)(1)(ii) of this AD is done.
(ii) Within 100 flight hours after doing the inspection required by paragraph (f)(2)(ii) of this AD, replace all hardware at the left-hand outboard location and the right-hand outboard location in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-19, Revision A, dated February 6, 2008; or Revision B, dated March 6, 2008. As of the effective date of this AD, Bombardier Alert Service Bulletin A84-57-19, Revision B, dated March 6, 2008, must be used. Replacing the barrel nuts on the outboard locations terminates the requirement to do the repetitive inspections specified in paragraph (g)(1)(i) of this AD.
(iii) Within 100 flight hours after doing the replacement required by paragraph (g)(1)(ii) of this AD, repeat the inspection specified in paragraph (f)(2) of this AD for the remaining barrel nuts identified with a marking of LH7940T SPS 01. Thereafter, repeat the inspection at intervals not to exceed 100 flight hours until the replacement of all hardware at those locations is done. Do the inspection and replacement in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-19, Revision A, dated February 6, 2008; or Revision B, dated March 6, 2008. As of the effective date of this AD, Bombardier Alert Service Bulletin A84-57-19, Revision B, dated March 6, 2008, must be used.
(2) If three barrel nuts having no cracking are found, do the actions specified in paragraphs (g)(2)(i), (g)(2)(ii), and (g)(2)(iii) of this AD.
(i) Within 50 flight hours after doing the inspection required by paragraph (f)(2)(ii) of this AD, repeat the inspection specified in paragraph (f)(2) of this AD. Thereafter, repeat the inspection at intervals not to exceed 50 flight hours until the replacement specified in paragraph (g)(2)(ii) of this AD is done.
(ii) Within 100 flight hours after doing the inspection required by paragraph (f)(2)(ii) of this AD, replace all hardware for one affected barrel nut at the outboard location, on the side with two affected barrel nuts, in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-19, Revision A, dated February 6, 2008; or Revision B, dated March 6, 2008. As of the effective date of this AD, Bombardier Alert Service Bulletin A84-57-19, Revision B, dated March 6, 2008, must be used. Replacing the barrel nut on the outboard location terminates the requirement to do the repetitive inspections specified in paragraph (g)(2)(i) of this AD.
(iii) Within 100 flight hours after doing the replacement required by paragraph (g)(2)(ii) of this AD, repeat the inspection specified in paragraph (f)(2) of this AD for the remaining barrel nuts identified with a marking of LH7940T SPS 01. Thereafter, repeat the inspection at intervals not to exceed 100 flight hours until the replacement of all hardware at those locations is done. Do the inspection and replacement in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-19, Revision A, dated February 6, 2008; or Revision B, dated March 6, 2008. As of the effective date of this AD, Bombardier Alert Service Bulletin A84-57-19, Revision B, dated March 6, 2008, must be used.
(3) If two barrel nuts having no cracking are found and both nuts are on the same side, do the actions specified in paragraphs (g)(3)(i), (g)(3)(ii), and (g)(3)(iii) of this AD.
(i) Within 100 flight hours after doing the inspection required by paragraph (f)(2)(ii) of this AD, repeat the inspection specified in paragraph (f)(2) of this AD. Thereafter, repeat the inspection at intervals not to exceed 100 flight hours until the replacement specified in paragraph (g)(3)(ii) of this AD is done.
(ii) Within 500 flight hours after doing the inspection required by paragraph (f)(2)(ii) of this AD, replace all hardware for one affected barrel nut at the outboard location that has two affected barrel nuts in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-19, Revision A, dated February 6, 2008; or Revision B, dated March 6, 2008. As of the effective date of this AD, Bombardier Alert Service Bulletin A84-57-19, Revision B, dated March 6, 2008, must be used. Replacing the barrel nut on the outboard location terminates the requirement to do the repetitive inspections specified in paragraph (g)(3)(i) of this AD.
(iii) Within 100 flight hours after doing the replacement required by paragraph (g)(3)(ii) of this AD, repeat the inspection specified in paragraph (f)(2) of this AD for the remaining barrel nut identified with a marking of LH7940T SPS 01. Thereafter, repeat the inspection at intervals not to exceed 100 flight hours until the replacement of all hardware at that location is done. Do the inspection and replacement in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-19, Revision A, dated February 6, 2008; or Revision B, dated March 6, 2008. As of the effective date of this AD, Bombardier Alert Service Bulletin A84-57-19, Revision B, dated March 6, 2008, must be used.
(4) If two barrel nuts having no cracking are found and are on opposite sides, within 100 flight hours after doing the inspection required by paragraph (f)(2)(ii) of this AD, repeat the inspection specified in paragraph (f)(2) of this AD. Thereafter, repeat the inspection at intervals not to exceed 100 flight hours until the replacement of all hardware at those locations is done. Do the inspection and replacement in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-19, Revision A, dated February 6, 2008; or Revision B, dated March 6, 2008. As of the effective date of this AD, Bombardier Alert Service Bulletin A84-57-19, Revision B, dated March 6, 2008, must be used.
(5) If one barrel nut having no cracking is found, within 100 flight hours after doing the inspection required by paragraph (f)(2)(ii) of this AD, repeat the inspection specified in paragraph (f)(2) of this AD. Thereafter, repeat the inspection at intervals not to exceed 100 flight hours until the replacement of all hardware at that location is done. Do the inspection and replacement in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-19, Revision A, dated February 6, 2008; or Revision B, dated March 6, 2008. As of the effective date of this AD, Bombardier Alert Service Bulletin A84-57-19, Revision B, dated March 6, 2008, must be used.
Actions accomplished before February 13, 2008, in accordance with Bombardier Alert Service Bulletin A84-57-19, dated February 1, 2008, are acceptable for compliance with the corresponding actions specified in this AD.
(i) For airplanes on which the actions specified in Bombardier Alert Service Bulletin A84-57-18, dated January 16, 2008, were accomplished before February 13, 2008, and on which no barrel nuts were found that were identified with a marking of LH7940T SPS 01: No further action is required by this AD.
As of February 13, 2008, no person may install a barrel nut, part number DSC228-16, identified with a marking of LH7940T SPS 01, on any airplane.
For airplanes on which barrel nuts are inspected in accordance with paragraph (g)(1)(iii), (g)(2)(iii), (g)(3)(iii), (g)(4), or (g)(5) of this AD: Within 3,000 flight hours after the effective date of this AD, replace all hardware for all remaining barrel nuts, part number DSC228-16, identified with a marking of LH7940T SPS 01. Do the replacement in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-19, Revision B, dated March 6, 2008. Replacement of all hardware for all affected barrel nuts constitutes terminating action for the repetitive inspections of this AD.
(l) For airplanes on which hardware for the barrel nut was replaced in accordance with Bombardier Alert Service Bulletin A84-57-19, dated February 1, 2008; or Revision A, dated February 6, 2008: Within 3,000 flight hours after the effective date of this AD, apply F13, Type 2 corrosion inhibiting compound to the affected bolts and barrel nuts in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-57-19, Revision B, dated March 6, 2008; except if it can be conclusively determined from a review of airplane maintenance records that F13, Type 2 corrosion inhibiting compound was applied to the affected bolts and barrel nuts, then no further action is required by this paragraph.
