AD 2016-16-15 Airworthiness Directives; Bombardier, Inc. Airplanes

Models named: DHC-8-400, -401, -402. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to Bombardier, Inc. Model DHC-8-400, -401, and -402 airplanes, certificated in any category, serial numbers (S/Ns) 4001 through 4431 inclusive.

Comply with this AD within the compliance times specified, unless already done.

For airplanes having S/Ns 4001 through 4055 inclusive: Do the actions required by paragraphs (g)(1) and (g)(2) of this AD. (1) Within 600 flight hours or 100 days after the effective date of this AD, whichever occurs first: Do a detailed inspection of the left-hand (LH) side and right-hand (RH) side nacelle A-frame structure for insufficient fillet radius, in accordance with “Part A—Inspection” of the Accomplishment Instructions of Bombardier Service Bulletin 84-54-19, dated April 18, 2013. If an insufficient fillet radius exists, before further flight, do an eddy current or fluorescent dye penetrant inspection for cracking, in accordance with “Part A—Inspection” of the Accomplishment Instructions of Bombardier Service Bulletin 84-54-19, dated April 18, 2013. (i) If any cracking is found: Before further flight, repair using a method approved by the Manager, New York Aircraft Certification Office (ACO), ANE-170, FAA; or Transport Canada Civil Aviation (TCCA); or Bombardier, Inc.'s TCCA Design Approval Organization (DAO). (ii) If no cracking is found: Before further flight, rework the structure, in accordance with “Part B—Rectification” of the Accomplishment Instructions of Bombardier Service Bulletin 84-54-19, dated April 18, 2013. (2) Within 6,000 flight hours or 36 months after the effective date of this AD, whichever occurs first: Rework the LH side and RH side nacelle A-frame structure, including doing a measurement of the clearance between the fasteners/A-frame structure and MLG stabilizer brace assembly and making sure no fouling condition exists, in accordance with paragraph 3.B., “Procedure,” of the Accomplishment Instructions of Bombardier Service Bulletin 84-54-21, dated May 9, 2013. If the clearance is found to be less than 0.100 inch (2.54 millimeters (mm)) between the fasteners/A-frame structure and MLG stabilizer brace assembly after the rework is done, or a fouling condition exists during the extension of the MLG after rework is done, before further flight, repair using a method approved by the Manager, New York ACO, ANE-170, FAA; or TCCA; or Bombardier, Inc.'s TCCA DAO.

This AD was prompted by reports of chafing damage due to insufficient clearance on the main landing gear (MLG) stabilizer brace, the nacelle A-frame structure, and the adjacent electrical wiring harnesses. An insufficient fillet radius might also exist on certain airplanes. We are issuing this AD to detect and correct chafing damage and subsequent premature cracking and fracture of the nacelle A-frame structure, which could result in failure of the MLG stabilizer brace and loss of the MLG down-lock indication, which could adversely affect the safe landing of the airplane.

None.