Attention:
Owners, operators and maintainers of Bombardier Inc. Aeroplanes Model BD-700-1A10 and BD-700-1A11, all serial numbers
| File Classification No.: | Z 5000-35 |
|---|---|
| RDIMS No.: | 19681416 |
| Document No.: | CASA 2024-03 |
| Issue No.: | 01 |
| Effective Date: | 2024-04-22 |
Purpose:
The purpose of this Civil Aviation Safety Alert (CASA) is to provide awareness of corrosion affecting the inboard flap spigot tubes and the internal structure of the mid and outboard flaps on BD-700-1A10 and BD-700-1A11 aeroplanes. This CASA recommends incorporation of the Maintenance Review Board Report (MRBR) and Aircraft Maintenance Manual (AMM) tasks addressing this corrosion into the Transport Canada (TC)-approved maintenance schedule and accomplishment of these tasks.
Background:
There have been in-service reports of corrosion affecting the inboard flap spigot tubes and the internal structure of the mid and outboard flaps on BD-700-1A10 and BD-700-1A11 aeroplanes.
Investigation of the inboard flap spigot tube corrosion revealed that an inconsistent cadmium plating coverage of the inner surface of the spigot tubes may lead to corrosion in that cavity. Service Bulletins (SBs) 700-27-085, 700-1A11-27-043, 700-27-5014, and 700-27-6014 were released on 31 March 2021 to introduce an inspection of the affected area and to initiate necessary corrective actions.
Corrosion of the internal structure of the mid and outboard flaps is due to the typical environmental exposure of the internal aluminum structure of the mid and outboard flaps. SBs 700-1A11-57-019, 700-57-053, 700-57-5008, 700-57-6008, 700-57-5502, 700-57-6502, 700-1A11-57-020, 700-57-054, 700-57-5009, 700-57-6009, 700-57-5503, and 700-57-6503 were released on 18 December 2020 to introduce an inspection of the respective flaps and to carry out necessary corrective actions.
While Airworthiness Directive (AD) CF-2020-49R1 mandated the amendment of the TC-approved maintenance schedule to incorporate BD-700-1A10 and BD-700-1A11 TLMC Part 3, Chapter 5, Task Number 57-51-00-201, which addresses corrosion of the internal structure of the inboard flaps, this maintenance inspection did not require inspection of the inboard flap spigot tubes for corrosion until its affiliated AMM Task 57-51-00-290-801 was updated on 25 July 2023 to require this inspection.
Prior to the creation of TLMC Part 3 Chapter 5, Task Numbers 57-51-00-202 and 57-51-00-203 for the inspection of the internal structure of the mid and outboard flaps, existing maintenance inspections for the mid and outboard flaps were for exterior inspection only and could not be relied upon to detect material degradation resulting from corrosion of the internal structure of the mid and outboard flaps.
Recommended action
Owners and operators are recommended to amend the TC-approved maintenance schedule to incorporate the following tasks and accomplish these tasks within the thresholds and intervals identified therein:
- BD-700-1A10 and BD-700-1A11 TLMC Part 3, Chapter 5, Task Number 57-51-00-201, dated 22 July 2022, and affiliated BD-700-1A10 and BD-700-1A11 AMM Task 57-51-00-290-801, dated 25 July 2023, to address inboard flap spigot tube corrosion.
- BD-700-1A10 and BD-700-1A11 TLMC Part 3, Chapter 5, Task Numbers 57-51-00-202 and 57-51-00-203, dated 22 July 2022, and affiliated BD-700-1A10 and BD-700-1A11 AMM Tasks 57-51-00-290-802 and 57-51-00-290-803, dated 19 December 2023, in order to address corrosion affecting the internal structure of the mid and outboard flaps.
Later revisions of the BD-700-1A10 and BD-700-1A11 TLMC Part 3, approved by TC and affiliated AMM tasks are also acceptable for incorporation into the TC-approved maintenance schedule.
Contact office:
For more information concerning this issue, contact a Transport Canada Centre; or contact Hilary Ross, Continuing Airworthiness in Ottawa, by telephone at 1-888-663-3639, by fax at 613-996-9178 or by e-mail at TC.CAWWEBFEEDBACK-retroactionWebMDLN.TC@tc.gc.ca.
Original signed by
Jenny Young
Chief, Continuing Airworthiness
National Aircraft Certification
The Transport Canada Civil Aviation Safety Alert (CASA) is used to convey important safety information and contains recommended action items. The CASA strives to assist the aviation industry's efforts to provide a service with the highest possible degree of safety. The information contained herein is often critical and must be conveyed to the appropriate office in a timely manner. The CASA may be changed or amended should new information become available.