AD 2016-24-03

(1) For airplanes that have accumulated 5,400 flight hours or more, or have been in service 32 months or more since the date of issuance of the original certificate of airworthiness or the date of issuance of the original export certificate of airworthiness, as of the effective date of this AD: Within 600 flight hours or 4 months, whichever occurs first after the effective date of this AD, do a detailed visual inspection for signs of cracks and corrosion of the barrel nut and cradle, in accordance with paragraph 3.B., “Procedures,” of the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-55-04, Revision C, dated May 3, 2016.

(2) For airplanes that have less than 5,400 flight hours, and have been in-service for less than 32 months since the date of issuance of the original certificate of airworthiness or the date of issuance of the original export certificate of airworthiness, as of the effective date of this AD: Before the accumulation of 6,000 total flight hours or 36 months since the date of issuance of the original certificate of airworthiness or the date of issuance of the original export certificate of airworthiness, whichever occurs first, do a detailed visual inspection of the barrel nut for signs of cracks and corrosion of the barrel nut and cradle, in accordance with paragraph 3.B., “Procedures,” of the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-55-04, Revision C, dated May 3, 2016.

Depending on the findings of any inspection required by paragraphs (g) and (j) of this AD, do the applicable actions in paragraphs (h)(1), (h)(2), and (h)(3) of this AD.

(1) If any barrel nut or cradle is found cracked or broken, before further flight, replace the barrel nut and associated hardware, in accordance with paragraph 3.B., “Procedures,” of the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-55-04, Revision C, dated May 3, 2016.

(i) Concurrently with the replacement of any barrel nut, do a detailed inspection for corrosion and damage of the bore of the fitting, in accordance with paragraph 3.B., “Procedures,” of the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-55-04, Revision C, dated May 3, 2016, and, before further flight, repair all corrosion and damage, in accordance with Bombardier Repair Drawing (RD) 8/4-55-1143, Issue 1, dated May 21, 2015. If the bore of the fitting cannot be repaired in accordance with Bombardier RD 8/4-55-1143, Issue 1, dated May 21, 2015, accomplish corrective actions in accordance with the procedures specified in paragraph (n)(2) of this AD.

(ii) Within 600 flight hours or 4 months, whichever occurs first, after the replacement of a cracked barrel nut, replace the remaining barrel nuts and their associated hardware at the horizontal-stabilizer-to-vertical-stabilizer attachment joints, in accordance with paragraph 3.B., “Procedures,” of the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-55-04, Revision C, dated May 3, 2016.

(2) If any corrosion is found on any barrel nut on the front or rear-spar joints, before further flight, replace the barrel nut accomplish corrective actions in accordance with the procedures specified in paragraph (n)(2) of this AD.

(3) If any corrosion above level 1, as defined in Bombardier Alert Service Bulletin A84-55-04, Revision C, dated May 3, 2016, is found on a barrel nut at the mid-spar joint, before further flight, replace the barrel nut and accomplish corrective actions in accordance with the procedures specified in paragraph (n)(2) of this AD.

(4) If all corrosion found is at level 1 or below, as defined in Bombardier Alert Service Bulletin A84-55-04, Revision C, dated May 3, 2016, on a barrel nut at the mid-spar joint, repeat the inspection specified in paragraph (g) of this AD at intervals not to exceed 600 flight hours or 4 months, whichever occurs first, until completion of the actions required by paragraph (k) of this AD.

For airplanes with PLI washers installed at the front and rear-spar joints, before further flight after accomplishing any inspection required by (g) of this AD and all applicable corrective actions required by paragraph (h) of this AD, check the bolt preload, and do all applicable corrective actions, in accordance with paragraph 3.B., “Procedures,” of the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-55-04, Revision C, dated May 3, 2016. Do all applicable corrective actions before further flight.

Repeat the inspection and preload check required by paragraphs (g) and (i) of this AD at intervals not to exceed 3,600 flight hours or 18 months, whichever occurs first, except as provided by paragraph (k) of this AD.

Inspection and replacement of all barrel nuts at the horizontal-stabilizer-to vertical-stabilizer attachment joints, in accordance with paragraph 3.B., “Procedures,” of the Accomplishment Instructions of Bombardier Alert Service Bulletin A84-55-04, Revision C, dated May 3, 2016, extends the next inspection required by paragraph (j) of this AD to within 6,000 flight hours or 36 months, whichever occurs first, after accomplishing the replacement.

At the applicable time specified in paragraph (l)(1) or (l)(2) of this AD, submit a report of the findings (both positive and negative) of each inspection required by this AD to Technical Help Desk—Q-series, telephone: 416-375-4000, fax: 416-375-4539, email: thd.qseries@aero.bombardier.com, using the inspection form in Bombardier Alert Service Bulletin A84-55-04, Revision C, dated May 3, 2016.

(1) If the inspection was done on or after the effective date of this AD: Submit the report within 30 days after the inspection.

(2) If the inspection was done before the effective date of this AD: Submit the report within 30 days after the effective date of this AD.