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AD/CL-600/70 - AC Contactors
Bombardier (Canadair) CL-600 (ChallengerBombardier (Canadair) CL-600 (Challenger) Series Aeroplanes
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Bombardier (Canadair) CL-600 (Challenger) Series Aeroplanes
| AD/CL-600/70 | AC Contactors | 8/2007 |
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| Applicability: | Model CL-600-2B19 aeroplanes, serial number 7003 through 7990 inclusive and 8000 through 8070 inclusive. |
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| Requirement: | 1. Unless already accomplished, visually inspect the AC service bus contactors 1K4XD and 2K4XD, part number (P/N) D-18ZZA, and the utility bus contactor K4XA, P/N D-7GRZ, to determine whether the AC contactors have a non-G9 terminal base plate. The above inspection is to be accomplished in accordance with Bombardier Service Bulletin (SB) 601R-24-123, Revision B, dated16 February 2007, or later revision approved by Chief, Continuing Airworthiness, Aircraft Certification, Transport Canada. |
| 2. If the contactors 1K4XD, 2K4XD or K4XA are determined to have a non-G9 terminal base plate, replace the AC service bus contactors 1K4XD and 2K4XD with new P/N D-18ZZC and the utility bus contactor K4XA with new P/ND-7GSZ, in accordance with SB 601R-24-123, Revision B, or later revision approved by Chief, Continuing Airworthiness, Aircraft Certification, Transport Canada. | |
| 3. AC contactor 1K4XD, 2K4XD or K4XA with a non-G9 terminal base plate may not be installed on any aircraft as a replacement part. | |
| Note: Transport Canada AD CF-2006-17R1 refers. | |
| Compliance: | For Requirements 1 and 2 - Within twelve months after the effective date of this Directive. |
| For Requirement 3 - As of the effective date of this Directive. | |
| This Airworthiness Directive becomes effective on 2 August 2007. | |
| Background: | Transport Canada has advised that there have been eight incidents of short-circuit failures of Tyco Hartman AC contactors - 1K4XD and K4XA - located in the avionics bay. All of the failed AC contactors had a terminal base plate made from non-G9 melamine material (Ultem 2200 material or black in colour). |
| In several cases, the arcing, which was initiated due to the presence of contaminants between the power studs, resulted in a fire that continued until power to the contactor was interrupted, either by burned-through wire or through the generator falling offline. |
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