Airworthiness Directive · Amendment 39-19908 · 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 Model DHC-8-400, -401, and -402 series airplanes, certificated in any category, serial numbers 4001 and subsequent.
The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. This AD was prompted by a report that certain elevator power control unit (PCU) arm fittings have nonconforming fillet radii. This AD requires an inspection for affected elevator PCU assemblies, inspections of affected elevator PCU arm fittings for nonconforming fillet radii and cracks, replacement if necessary, and re- identification of the affected elevator PCU assemblies. The FAA is issuing this AD to address the unsafe condition on these products.
Affected elevator PCU assemblies are those having part number 85527021-005 or 85527021-006, and having serial number MMC4255 through MMC4276 inclusive.
For airplanes having serial numbers 4001 through 4620 inclusive, within 8,000 flight cycles on the elevator PCU assembly after the effective date of this AD, or before the accumulation of 30,000 total flight cycles on the elevator PCU assembly, whichever occurs first: Do the actions specified in paragraphs (h)(1) and (2) of this AD.
(1) Inspect to determine the part number and serial number of each elevator PCU assembly installed on the airplane. A review of airplane maintenance records is acceptable in lieu of this inspection if the part number and serial number of the elevator PCU assembly can be conclusively determined from that review.
(2) If, during any inspection or records review required by paragraph (h)(1) of this AD, any affected elevator PCU assembly is found, do a detailed inspection of the elevator PCU arm fittings for undersized fillet radii and cracks of the fillet radii in accordance with Part A of the Accomplishment Instructions of De Havilland Aircraft of Canada Limited Service Bulletin 84-55-10, Revision A, dated July 25, 2019. If no undersized fillet radii or cracks of the fillet radii are found, before further flight, re-identify the affected elevator PCU assembly in accordance with the Accomplishment Instructions of De Havilland Aircraft of Canada Limited Service Bulletin 84-55-10, Revision A, dated July 25, 2019.
If during any inspection of the elevator PCU arm fittings required by paragraph (h)(2) of this AD, any undersized fillet radii or cracks of the fillet radii are found, before further flight, replace the elevator PCU arm fittings and re-identify each affected elevator PCU assembly in accordance with Part B of the Accomplishment Instructions of De Havilland Aircraft of Canada Limited Service Bulletin 84-55-10, Revision A, dated July 25, 2019.
As of the effective date of this AD, no person may install an affected elevator PCU assembly on any airplane, unless it has been re-identified in accordance with the Accomplishment Instructions of De Havilland Aircraft of Canada Limited Service Bulletin 84-55-10, Revision A, dated July 25, 2019.
