TP 7245E 1 of 3
AD Number: CF
- 201 4 - 45 Issue Date: 23 December 201 4 

# AIRWORTHINESS DIRECTIVE

The following airworthiness directive (AD) may be applicable to an aircraft which our records indicate is registered in your name. ADs are issued pursuant to **Canadian Aviation Regulation**  (CAR) 521 Division X . Pursuant to CAR 605.84 and the further details of CAR Standard 625, Appendix H , the continuing airworthiness of a Canadian registered aircraft is contingent upon compliance with all applicable ADs. Failure to comply with the requirements of an AD may invalidate the flight authorization of the aircraft. Alternative means of compliance shall be applied for in accordance with CAR 605.84 and the above

- referenced Standard

. This AD has been issued by the Continuing Airworthiness Division (AARDG), National Aircraft Certification Branch, Transport Canada, Ottawa, telephone 61 3 952

- 4357. Number: CF

- 201 4

- 45 Effective Date: 7 January 2 0 1 5
ATA: 54 Type Certificate: A

- 142 Subject : Nacelle

– A

- Frame Structure

– Insufficient Fillet Radius and Fouling with Main Landing Gear Stabilizer Brace and the Electrical Wiring Harnesses Applicability: Bombardier Inc. model DHC

- 8

- 400,

- 401 and

- 402 aeroplanes, serial numbers 4001 through 4431. Compliance: As indicated below, unless already accomplished. Background: The aeroplane manufacturer has discovered that an insufficient fillet radius may exist on the flange of the nacelle A

- frame structure on certain aeroplanes. There have also been several in

- service reports of chafing damage on the main landing gear (MLG) stabilizer brace , the nacelle A

- frame structure and its adjacent electrical wiring harnesses due to insufficient clearance. An insufficient fillet radius and chafing damage on the nacelle A

- frame structure and MLG stabilizer brace could lead to premature cracking. Fractur e of the nacelle A

- frame structure or failure of the MLG stabilizer brace could adversely affect the safe landing of the aeroplane. The damage to the electrical wiring harnesses could result in the loss of the MLG downlock indication.
This AD mandates the inspection and rework of the nacelle A

- frame structure, and the rework of the forward MLG stabilizer brace assembly and the electrical harnesses in the nacelle area adjacent to the A

- frame structure.
Corrective Actions:
Part I

– Inspection , Rework , and Rev ersal of Fasteners o n the Nacelle A
- Frame Structure
- Applicable to aeroplane serial numbers 4001 through 4055:
A. Within 600 hours air time or 100 days, whichever occurs first, from the effective date of this AD, inspect and rectify, as required, the left hand (LH) side and right hand (RH) side nacelle A

- frame structure in accordance with the Accomplishment Instructions in Bombardier Service Bulletin ( SB ) 84

- 54

- 19 , Initial Issue, dated 18 April 2013 , or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada. If any cracks are found, contact the Q

- Series Technical Help Desk for an approved repair and incorporate the r epair before further flight. The approved repair must specifically reference this AD.
B. Within 6000 hours air time or 36 months, whichever occurs first, from the effective date of this AD, rework the LH side and RH side nacelle A

- frame structure in accordanc e with the Accomplishment Instructions in Bombardier SB 84

- 54

- 21, Initial Issue, dated 9 May 2013, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.

Pursuant to CAR 202.51 the registered owner of a Canadian aircraft shall, within seven days, notify the Minister in writing of any change of his or her name or address. For all changes to your mailing address, contact your TC Regional Aircraft Registration Office at 1

- 800

- 305

- 2059, option 1 for English, 2 for Aircraft Registration and then select the appropriate region. 24

- 0022 (01

- 2005)CF
- 2014 - 45 2 of 3 If any of the following conditions are found, contact the Q Series Tech nical Help Desk for an approved disposition/repair and incorporate the disposition/repair, as required, before further flight:
1. A clearance of less than 2.54mm ( 0.100in ) exists between the fasteners/A

- frame structure and the MLG stabilizer brace assembly in the retracted position, after the rework is accomplished; or
2. A fouling condition exists during the extension of the MLG after the rework is accomplished. The approved disposition/repair must specifically reference this AD. Incorporation of Bomb ardier Modsum IS4Q5450002 also meets the requirements of Part I, paragraph B of this AD.
Part I I

– Inspection and Rework of the Nacelle A
- Frame Structure
- Applicable to aeroplane serial numbers 4056 through 4426:
A. Initial Inspection:
Within 600 hours air t ime or 100 days, whichever occurs first, from the effective date of this AD, perform a detailed visual inspection (DVI) of the LH side and RH side nacelle A

- frame structure and upper surface of the MLG stabilizer brace lug in accordance with the Accomplish ment Instructions in Part A of Bombardier SB 84

- 54

- 20 , Revision B, dated 2 October 2014 , or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada.
1. If any damage is found, contact the Q Series Technical Help Desk for an approved disposition/repair and incorporate the disposition/repair, before further flight. The approved disposition/repair must specifically reference this AD.
2. If no damage is found, p roceed to Part II, paragraph B of this AD.
B. Repetitive Inspections: Subsequently, at intervals not to exceed 600 hours air time, repeat the DVI specified in Part II, paragraph A, of this AD until Part II, paragraph C of this AD is accomplished.
C. Terminating Action to the Inspections in Part II of this AD: Within 6000 hours air time, or 36 months, whichever occurs first, from the effective date of this AD, rework the LH side and RH side nacelle A

- frame structure in accordance with the Accomplishment Instructi ons in Part B of Bombardier SB 84

- 54

- 20 , Revision B, dated 2 October 2014 , or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada. If any of the following conditions are found, contact the Q Series Technical Help Desk for an approved disposition/repair and incorporate the disposition/repair, as required, before further flight:
1. A ny crack s found on the nacelle A

- frame structure ; or
2. A clearance of less than 2.54mm ( 0.100in ) exists between the A

- frame structure and the MLG stabilizer brace assembly in the retracted position, after the rework is accomplished. The approved disposition/repair must specifically reference this AD.CF
- 2014 - 45 3 of 3 Rework of the LH side and RH side nacelle A

- frame structure in accordance with the Initial Issue or Revision A of Bombardier SB 84

- 54

- 20, dated 25 April 2013 and 9 April 2014, respectively, prior to the effective date of this AD, also meets the requirements of Part II, paragraph C of this AD. Incorporation of Bombardier ModSum IS4Q5450003 also meets the requirements of Part II, paragraph C of this AD

. Rework of the LH side and RH side nacelle A

- frame structure in accordance with Part II, paragraph C of this AD, constitutes terminating action to the inspections in Part II, paragraphs A and B of this AD.
Part II I

– Modification of the MLG Stabilizer Brace Assembly

– Applicable to Aeroplane Serial Numbers 4001 through 4431 with MLG Stabilizer Brace Assembly Part Number 46400 - 27 installed: Within 6000 hours air time, or 36 months, whichever occurs first, fro m the effective date of this AD, incorporate Bombardier Modsum 4

- 902416. Bombardier SB 84

- 32

- 112, Revision B, dated 12 September 2014, or later revisions approved by the Chief, Continuing Airworthiness, Transport Canada, provides approved instructions for incorporating Modsum 4

- 902416. Incorporation of Modsum 4

- 902416 in accordance with the Initial Issue or Revision A of Bombardier SB 84

- 32

- 112, dated 20 December 2012, and 16 April 2014 , respectively, prior to the effecti ve date of this AD, also meets the requirements of Part III of this AD.
Part I V

– Rework of the Electrical Wiring Harnesses in the Nacelle Area Adjacent to the A
- Frame Structure

– Applicable to A eroplane Serial Numbers 4001 through 4411:
Within 6000 hours air time, or 36 months, whichever occurs first, from the effective date of this AD, rework the LH side and RH side electrical wiring harnesses in accordance with Bombardier SB 84

- 32

- 114, Revision A, dated 18 September 2013, or later revisions approved by t he Chief, Continuing Airworthiness, Transport Canada. If any damage is found on the A

- frame structure or MLG stabilizer brace, contact the Q Series Technical Help Desk for an approved repair and incorporate the repair before further flight. The approved re pair must specifically reference this AD. Rework of the LH side and RH side electrical wiring harnesses in accordance with the Initial Issue of SB 84

- 32

- 114, dated 6 June 2013, prior to the effective date of this AD, also meets the requirements of Part IV of this AD. Incorporation of Bombardier Modsums IS4Q2400028 or IS4Q2400029, as applicable, also meets the requirements of Part IV of this AD.
Authorization: For the Minister of Transport,
O R I G I N A L S I G N E D B Y Derek Ferguson Chief, Continuing Airworthiness
Contact: Robert Farinas , Continuing Airworthiness, Ottawa, telephone 613

- 952

- 4357, facsimile 613

- 996

- 9178 or e

- mail AD

- CN@tc.gc.ca or any Transport Canada Centre.