Airworthiness Directive · Amendment 39-22666 · Stabilizers
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-8-401 and -402 airplanes, certificated in any category, having serial numbers 4001 and 4003 through 4633 inclusive.
The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and - 402 airplanes. This AD was prompted by reports that the saddle washer (radius filler) for the front and rear spar joints may have been incorrectly manufactured for several years. This AD requires inspecting the horizontal stabilizer to vertical joint for gaps and bending of the saddle washer and adjacent washers, and replacing parts if necessary. The FAA is issuing this AD to address the unsafe condition on these products.
Within 8,000 flight hours after the effective date of this AD, perform a detailed inspection for signs of gapping or bending of the saddle washers and adjacent washers in the front spar and rear spar horizontal/vertical stabilizer joint fitting in accordance with Section 3.B., Part A, of the Accomplishment Instructions of De Havilland Aircraft of Canada Limited Service Bulletin 84-55-12, Revision B, dated April 20, 2023.
If any gaps or bending of the washers are found during the inspection required by paragraph (g) of this AD, before further flight, replace the saddle washer, washers, PLI washer, bolt, and barrel nut, as applicable, in accordance with Section 3.B., Part B, of the Accomplishment Instructions of De Havilland Aircraft of Canada Limited Service Bulletin 84-55-12, Revision B, dated April 20, 2023.
