Transport Canada issues AD CF-2026-37 TLMC-ALI for DHC-8-401/402 aeroplanes; new or more restrictive ALI tasks

Transport Canada issues AD CF-2026-37 TLMC-ALI for DHC-8-401/402 aeroplanes; new or more restrictive ALI tasks

Airworthiness Directive CF-2026-37- Time Limits/Maintenance Checks (TLMC) – Airworthiness Limitation Items (ALI)

TP 7245E 1 of 5 AD Number: CF-2026-37

AIRWORTHINESS DIRECTIVE This Airworthiness Directive (AD) is issued pursuant to Canadian Aviation Regulation (CAR) 521.427. No person shall conduct a take-off or permit a take-off to be conducted in an aircraft that is in their legal custody and control, unless the requirements of CAR 605.84 pertaining to ADs are met. Standard 625 - Aircraft Equipment and Maintenance Standards Appendix H provides information concerning alternative means of compliance (AMOC) with ADs. Number: CF-2026-37 ATA: 05 Effective Date: 4 September 2026 Type Certificate: A-142 Subject: Time Limits/Maintenance Checks (TLMC) – Airworthiness Limitation Items (ALI) Applicability: De Havilland Aircraft of Canada Limited (DHC) (Formerly Bombardier Inc.) model DHC-8-401 and DHC-8- 402 aeroplanes, all serial numbers. Compliance: As indicated below, unless already accomplished. Background: The ALI for the model DHC-8-401 and DHC-8-402 aeroplanes are defined and published in the DHC Maintenance Requirements Manual (MRM) PSM 1-84-7 Part 2, approved by Transport Canada (TC). The instructions contained in the DHC MRM PSM 1-84-7 Part 2 have been identified as mandatory actions for continued airworthiness. Failure to comply with these instructions could result in an unsafe condition. DHC has introduced changes to the DHC MRM PSM 1-84-7 Part 2 ALI wherein new tasks have been added and a number of existing tasks have been revised to become more restrictive. This AD requires completion of the new or more restrictive limitations within their thresholds and repeat intervals or within the discard time as applicable. Corrective Actions: Within the thresholds and repeat intervals identified within the tasks, or discard time, as applicable, complete the new or more restrictive limitations contained in DHC MRM PSM 1-84-7 Part 2 ALI manual identified in Table 1 below, as applicable to the aeroplane model and configuration. Compliance with superseding Temporary Revisions (TR) affecting these tasks or later revisions of DHC MRM PSM 1-84-7 Part 2 ALI manual, approved by TC, also meets the intent of this AD.

CF-2026-37 2 of 5 Table 1: ALI Tasks, TR ALI task number Config LTR Description TR revision Issue Date Section 532066F103 A Detailed Inspection and Special Detailed Inspection of the VHF No.3 (or ACARS) Antenna Installation, Sta. X331 APPLICABILITY: (Post Modsum 4−400200) or (Post Modsum 4−121296) or (Post Modsum 4−110466) or (Post Modsum 4−124091) or (Post Modsum 4−903208) and ((Pre Modsum 4−458965) and (Pre Modsum 4−459885)) TR ALI- 0236 10-Feb- 2025 2 Structural Inspection

532066F103 B Detailed Inspection and Special Detailed Inspection of the VHF No.3 (or ACARS) Antenna Installation, Sta. X331 APPLICABILITY: (Post Modsum 4−400200) or (Post Modsum 4−121296) or (Post Modsum 4−110466) or (Post Modsum 4−124091) or (Post Modsum 4−903208) and ((Post Modsum 4−458965) or (Post Modsum 4−459885)) and (EHGW) TR ALI- 0236 10-Feb- 2025 2 Structural Inspection 541008F101 B Detailed Inspection of the Nacelle Mid Frame Upper Left Aft EMS Strut Attachment Fitting (Lugs), LH and RH APPLICABILITY: ((Post Modsum 4−156156) and (Pre Modsum 4−113870) and (Pre Modsum 4−113968)) and (BGW) TR ALI- 0201 18-Apr- 2019 2 Structural Inspection 542015F105 C Detailed Inspection and Special Detailed Inspection of the Nacelle ’A’ Frame Inboard and Outboard Vertical Leg Inner Flanges Attachment Holes (Adjacent to Edge of Flange), LH and RH APPLICABILITY:(Post Modsum 4−113305) and (BGW) TR ALI- 0201 18-Apr- 2019 2 Structural Inspection 542015F105 D Detailed Inspection and Special Detailed Inspection of the Nacelle ’A’ Frame Inboard and Outboard Vertical Leg Inner Flanges Attachment Holes (Adjacent to Edge of Flange), LH and RH APPLICABILITY:(Post Modsum 4−113305) and (IGW or HGW or EHGW) TR ALI- 0201 18-Apr- 2019 2 Structural Inspection 551004F101 B Special Detailed Inspection of the Horizontal Stabilizer Front Spar Joint at Sta. YH33.0, LH and RH APPLICABILITY: ((Post Modsum 4−458965) or (Post Modsum 4−459885)) and (EHGW) TR ALI- 0230 17-Aug- 2022 2 Structural Inspection 712001F102 H Detailed Inspection of the Powerplant Mount, Engine Isolator, Forward Left (Bracket only, excluding HTCS Link Ass’ly.), LH and RH APPLICABILITY: (Post Modsum 4−184092) and (IGW or HGW or EHGW) TR ALI- 0202 18-Apr- 2019 2 Structural Inspection

CF-2026-37 3 of 5 Table 1: ALI Tasks, TR continuation ALI task number Config LTR Description TR revision Issue Date Section 712002F101 B Detailed Inspection and Special Detailed Inspection of the Powerplant Mount, Engine Isolator, Forward Top, LH and RH APPLICABILITY: ((Post Modsum 4−156156) and (Pre Modsum 4−113870) and (Pre Modsum 4−113968)) and (BGW) TR ALI- 0202 18-Apr- 2019 2 Structural Inspection 712002F101 C Powerplant Mount, Engine Isolator, Forward Top, LH and RH APPLICABILITY: ((Post Modsum 4−156194) or (Post Modsum 4−113870) or (Post Modsum 4−113968)) and (BGW) TR ALI- 0202 18-Apr- 2019 2 Structural Inspection 712004F101 B Detailed Inspection and Special Detailed Inspection of the Powerplant Mount, Engine Isolator, Aft Left, LH and RH APPLICABILITY: ((Post Modsum 4−156156) and (Pre Modsum 4−113870) and (Pre Modsum 4−113968)) and (BGW) TR ALI- 0202 18-Apr- 2019 2 Structural Inspection 712004F101 C Detailed Inspection and Special Detailed Inspection of the Powerplant Mount, Engine Isolator, Aft Left, LH and RH APPLICABILITY: ((Post Modsum 4−156194) or (Post Modsum 4−113870) or (Post Modsum 4−113968)) and (BGW) TR ALI- 0202 18-Apr- 2019 2 Structural Inspection 712005F101 B Detailed Inspection and Special Detailed Inspection of the Powerplant Mount, Engine Isolator, Aft Right, LH and RH APPLICABILITY: ((Post Modsum 4−156156) and (Pre Modsum 4−113870) and (Pre Modsum 4−113968)) and (BGW) TR ALI- 0202 18-Apr- 2019 2 Structural Inspection 712005F101 C Detailed Inspection and Special Detailed Inspection of the Powerplant Mount, Engine Isolator, Aft Right, LH and RH APPLICABILITY: ((Post Modsum 4−156194) or (Post Modsum 4−113870) or (Post Modsum 4−113968)) and (BGW) TR ALI- 0202 18-Apr- 2019 2 Structural Inspection 54-00-01- 704 G Pins − MLG Yoke Attachment APPLICABILITY: (Post Modsum 4−170096) and (BGW) TR ALI- 0233 27-Dec- 2024 3 Structural Safelife 54-20-01- 701 P ’A’ Frame (Drag Strut Attach.) APPLICABILITY: ((Post Modsum 4−113159 and Post Modsum 4−113776 and Post Modsum 4−114003) or (Post Modsum 4−113159 and Post Modsum 4−123818 and Post Modsum 4−114003) or (Post Modsum 4−113159 and Post Modsum 4−170073 and Post Modsum 4−114003) or (Post Modsum 4−113159 and Post Modsum 4−170060 and Post Modsum 4−114003) (Rework: A/C 4081 − 4591)) and (BGW) TR ALI- 0233 27-Dec- 2024 3 Structural Safelife 54-20-01- 701 Q ’A’ Frame (Drag Strut Attach.) APPLICABILITY: (Post Modsum 4−113159 and Post Modsum 4−170060 and Pre Modsum 4−114003) (New Prod: A/C 4458, 4461, 4462, 4464 to 4591)) and (BGW) TR ALI- 0233 27-Dec- 2024 3 Structural Safelife

CF-2026-37 4 of 5 Table 1: ALI Tasks , TR continuation ALI task number Config LTR Description TR revision Issue Date Section 54-20- 01-701 R ’A’ Frame (Drag Strut Attach.) APPLICABILITY: ((Post Modsum 4−113159 and Post Modsum 4−113776 and Pre Modsum 4−114003) (Rework: A/C 4081 − 4426)) and (BGW) TR ALI- 0233 27-Dec- 2024 3 Structural Safelife 54-20- 01-701 V ’A’ Frame (Drag Strut Attach.) APPLICABILITY: (Post Modsum 4−113305 and Post Modsum IS4Q5450002) (Rework: A/C 4003 − 4055)) and (BGW) TR ALI- 0233 27-Dec- 2024 3 Structural Safelife 54-20- 01-703 G Pin − MLG Drag Strut Attach. APPLICABILITY: (Post Modsum 4−170096) and (BGW) TR ALI- 0233 27-Dec- 2024 3 Structural Safelife 54-20- 01-704 F MLG Side Brace Fitting APPLICABILITY: (Post Modsum 4−114003 (Rework: A/C 4081 − 4591)) and (BGW) TR ALI- 0233 27-Dec- 2024 3 Structural Safelife 54-20- 01-704 G MLG Side Brace Fitting APPLICABILITY: (Post Modsum 4−156138 and Pre Modsum 4−114003) (New Prod: A/C 4081 − 4591)) and (BGW) TR ALI- 0233 27-Dec- 2024 3 Structural Safelife 54-20- 01-705 M Pins − Side Brace Fitting APPLICABILITY: (Post Modsum 4−170096) and (BGW) TR ALI- 0233 27-Dec- 2024 3 Structural Safelife 54-20- 01-705 O Pins − Side Brace Fitting APPLICABILITY: (Post Modsum 4−170096) and (BGW) TR ALI- 0233 27-Dec- 2024 3 Structural Safelife 54-20- 01-707 O ’A’ Frame (MLG Side Brace Fitting Attach.) APPLICABILITY: ((Post Modsum 4−113159 and Post Modsum 4−113776 and Post Modsum 4−114003) or (Post Modsum 4−113159 and Post Modsum 4−123818 and Post Modsum 4−114003) or (Post Modsum 4−113159 and Post Modsum 4−170073 and Post Modsum 4−114003) or (Post Modsum 4−113159 and Post Modsum 4−170060 and Post Modsum 4−114003) (Rework: A/C 4081 − 4591)) and (BGW) TR ALI- 0233 27-Dec- 2024 3 Structural Safelife 54-20- 01-707 P ’A’ Frame (MLG Side Brace Fitting Attach.) APPLICABILITY: (Post Modsum 4−113159 and Post Modsum 4−170060 and Pre Modsum 4−114003) (New Prod: A/C 4458, 4461, 4462, 4464 to 4591)) and (BGW) TR ALI- 0233 27-Dec- 2024 3 Structural Safelife 54-20- 01-707 Q ’A’ Frame (MLG Side Brace Fitting Attach.) APPLICABILITY: (Post Modsum 4−113159 and Post Modsum 4−113776 and Pre Modsum 4−114003) (Rework: A/C 4081 − 4426)) and (BGW) TR ALI- 0233 27-Dec- 2024 3 Structural Safelife 54-20- 01-707 U ’A’ Frame (MLG Side Brace Fitting Attach.) APPLICABILITY: ((Post Modsum 4−113305 and Post Modsum IS4Q5450002) (Rework: A/C 4003 − 4055)) and (BGW) TR ALI- 0233 27-Dec- 2024 3 Structural Safelife

CF-2026-37 5 of 5

Authorization: For the Minister of Transport, ORIGINAL SIGNED BY Liviu Badita Acting Chief, Continuing Airworthiness Issued on 5 August 2026 Contact: Mihaela Kramer, Continuing Airworthiness, Ottawa, telephone 1-888-663-3639, or e-mail TC.AirworthinessDirectives-Consignesdenavigabilite.TC@tc.gc.ca or any Transport Canada Centre.