Airworthiness Directive · Amendment 39-17970 · Flight controls
Bombardier, Inc. Airplanes
This AD applies to Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes, certificated in any category, serial numbers 4166 through 4175, inclusive.
We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes. This AD was prompted by reports of rudder bearings falling out of the fore rudder hinge bracket during assembly. This AD requires a proof load test and detailed inspections; and installation of a new bearing, reaming, or repair of the bearing if necessary. We are issuing this AD to detect and correct improper bearing installation, which could result in abnormal wear and potential increased freeplay in the rudder system, and resultant airframe vibration, leading to compromise of the flutter margins of the airplane.
Within 2,000 flight hours or 12 months after the effective date of this AD, whichever occurs first, do a proof load test for slippage and freeplay (relative movement between the bearing and fitting), in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 84-27-44, Revision ‘B,’ dated February 11, 2014. If no slippage or freeplay is detected during the proof load test required by this paragraph, before further flight, identify the area with a marker and apply sealant if missing, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 84-27-44, Revision ‘B,’ dated February 11, 2014; and after identifying the area with a marker and applying sealant, no further action is required by this AD.
If any slippage or freeplay (relative movement between the bearing and fitting) is detected during the test required by paragraph (g) of this AD, before further flight, do the actions specified in paragraphs (h)(1) and (h)(2) of this AD.
(1) Do a detailed inspection of bearing DSC8-6 for damage, corrosion, and dimension conformity, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 84-27-44, Revision ‘B,’ dated February 11, 2014. If damage, corrosion, or dimension non-conformity is found, before further flight, install new bearing DSC8-6, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 84-27-44, Revision ‘B,’ dated February 11, 2014.
(2) Do a detailed inspection of the fitting bore of the fore rudder hinge bracket assembly for wear, damage, corrosion, and dimension conformity, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 84-27-44, Revision ‘B,’ dated February 11, 2014.
(i) If damage, corrosion, or dimension non-conformity is found during the inspection required by paragraph (h)(2) of this AD, before further flight, ream the inside diameter, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 84-27-44, Revision ‘B,’ dated February 11, 2014.
(ii) If bore wear or damage beyond 0.8140-inch diameter is found during the inspection required by paragraph (h)(2) of this AD, before further flight, repair using a method approved by the Manager, New York ACO, ANE-170, Engine and Propeller Directorate, FAA; or Transport Canada Civil Aviation (TCCA); or Bombardier, Inc.'s TCCA Design Approval Organization (DAO). If approved by the DAO, the approval must include the DAO-authorized signature.
