Airworthiness Directive · Amendment 39-18518 · Electrical power
Bombardier, Inc. Airplanes
This AD applies to Bombardier, Inc. Model DHC-8-102, -103, -106, -201, -202, -301, -311, and -315 airplanes; certificated in any category; serial numbers 003 through 672 inclusive.
We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model DHC-8-102, -103, -106, -201, -202, -301, -311, and -315 airplanes. This AD was prompted by a report of a pilot commanding an in-flight engine shut down in response to a low oil pressure warning indication. Further investigation revealed the mounting studs in the engine mounted alternating current (AC) generator mounting plate were pulled out of position and the threaded interface in the plate was corroded. This AD requires repetitive inspections for discrepancies on certain AC generator mounting adapters, and replacing discrepant adapters with serviceable ones. This AD also requires revising the maintenance program to incorporate a repetitive task specified in certain temporary revisions. We are issuing this AD to detect and correct corrosion in the AC generator mounting plate, which could result in a gap between the AC generator and the generator mounting plate, and cause loss of engine oil and consequent engine failure.
Within 6,000 flight hours, or 36 months, or when the AC generator is removed for service, whichever occurs first, after the effective date of this AD: Do a general visual inspection and a mechanical inspection for discrepancies (i.e., damage, corrosion, and failed mechanical inspection) on AC generator mounting adapters having part number (P/N) 31708-500 and P/N 31708-501, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 8-24-88, Revision A, dated September 23, 2014. If any discrepancy (i.e., damage, corrosion, or failed mechanical inspection) is found, before further flight, replace the AC generator mounting adapter with a serviceable mounting adapter having P/N 31708-510, P/N 31708-511, P/N 31708-500, or P/N 31708-501, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 8-24-88, Revision A, dated September 23, 2014.
For in-service mounting adapters that have P/N 31708-500 or P/N 31708-501: Repeat the general visual and mechanical inspection required by paragraph (g) of this AD thereafter at intervals not to exceed 6,000 flight hours, or 36 months after the most recent inspection, or when the AC generator is removed for service, whichever occurs first.
For airplanes having AC generator mounting adapters that have P/N 31708-500 or P/N 31708-501: Within the later of the times specified in paragraphs (i)(1) and (i)(2) of this AD, replace the AC generator mounting adapter with a new AC generator mounting adapter having P/N 31708-510 or P/N 31708-511.
(1) Before the accumulation of 120 months on the AC generator mounting adapter.
(2) Within 12 months, or 2,000 flight hours, or when the generator is removed from service, whichever occurs first after the effective date of this AD.
For airplanes having AC generator mounting adapters that have P/N 31708-510 or P/N 31708-511: Within 30 days after the effective date of this AD, revise the airplane maintenance or inspection program, as applicable, by incorporating maintenance review board (MRB) Report Task 2420/14, “Functional Check (pull test) of the AC generator adapter kit,” in the applicable maintenance program manual specified in paragraph (j)(1), (j)(2), or (j)(3) of this AD. The initial compliance time for MRB Task 2420/14 is prior to the accumulation of 10,000 total flight hours or within 60 months since installation of the part, whichever occurs first.
(1) For Model DHC-8-102, -103, and -106 airplanes: de Havilland Dash 8 Series 100 MRB Report Temporary Revision MRB-153, dated July 10, 2012, to Section 2—Systems, of the de Havilland Dash 8 Series 100 Maintenance Program Manual PSM 1-8-7.
(2) For Model DHC-8-201 and -202 airplanes: de Havilland Dash 8 Series 200 MRB Report Temporary Revision MRB 2-31, dated July 10, 2012, to Section 2—Systems, of the de Havilland Dash 8 Series 200 Maintenance Program Manual PSM 1-82-7.
(3) For Model DHC-8-301, -311, and -315 airplanes: de Havilland Dash 8 Series 300 MRB Report Temporary Revision MRB3-162, dated July 10, 2012, to Section 2—Systems, of the de Havilland Dash 8 Series 300 Maintenance Program Manual PSM 1-83-7.
After the maintenance or inspection program has been revised as required by paragraph (j) of this AD, no alternative actions (e.g., inspections) or intervals may be used unless the actions or intervals are approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (m)(1) of this AD.
