Transport Transports 

Canada Canada

 TP 7245E

 

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 613 952-4357.

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. 

To request a change of address, contact the Civil Aviation Communications Centre (AARC) at Place de Ville, Ottawa, Ontario K1A 0N8, or 1-800-305-2059, or www.tc.gc.ca/civilaviation/communications/centre/ address.asp 

24-0022 (01-2005)

1/2 No.

CF-2013-20R1

Issue Date 

 30 December 2013 

Number: CF-2013-20R1 

Subject: Forward Passenger Door – Cracking of the Airstair Step Assembly 

Effective: 13 January 2014 

Revision: Supersedes AD CF-2013-20, issued 25 July 2013. 

Applicability: Bombardier Inc. model DHC-8-400, -401 and -402 aeroplanes, serial numbers 4001 

and subsequent. 

Compliance: As indicated below, unless already accomplished. 

Background: There has been one in-service report of several cracks being found on the forward 

passenger airstair door step assembly between the steps and the sidewall panels. The 

investigation revealed that the application of potting compound may have been omitted 

during the bonding at the joint of the airstair door steps and the sidewalls. The omission 

of potting compound could cause the bonding sealant to crack. The cracks, if not 

detected, could propagate to result in the structural failure of the steps. 

In the event of an emergency egress situation, the failure of the airstair step assembly 

could impede the evacuation of passengers. 

This AD mandates the replacement of the affected forward passenger airstair step 

assembly with a new or reworked step assembly. 

Revision 1 of this AD provides additional instructions for performing an electronic tap test 

of the airstair step assembly if the Serial Number (S/N) of the airstair step assembly

cannot be found. 

Corrective 

Actions: 

Part I – Inspection & Replacement of Affected Doors – Applicable to Aeroplane 

Serial Numbers 4001 through 4393: 

A. Within 320 days from the effective date of this AD, inspect the S/N of the airstair step 

assembly in accordance with the Accomplishment Instructions in Bombardier Service 

Bulletin (SB) 84-52-77, Revision B, dated 31 October 2013, or later revisions 

approved by the Chief, Continuing Airworthiness, Transport Canada. 

B. If the S/N of the airstair step assembly cannot be found, or is illegible, perform an 

electronic tap test in accordance with the accomplishment instructions of the 

above-mentioned SB. 

1. If the existence of epoxy compound is confirmed, re-identify the airstair step 

assembly in accordance with the Accomplishment Instructions of the 

above-mentioned SB. Proceed to Part II of this AD. 
No.

N° CF-2013-20R1 2/2 

2. If the existence of epoxy compound is not confirmed, proceed to paragraph D of 

this AD. 

C. If the S/N of the airstair step assembly is not in the affected range listed in section 

1.A. of the above-mentioned SB, no further action is required. Proceed to Part II of 

this AD. 

D. If the S/N of the airstair step assembly is in the affected range listed in section 1.A. of 

the above-mentioned SB, or the existence of epoxy compound is not confirmed, 

within 6000 hours air time from the effective date of this AD, replace the airstair step 

assembly in accordance with the Accomplishment Instructions of the 

above-mentioned SB. Proceed to Part II of this AD. 

For aeroplanes where the S/N of the airstair step assembly can be found, inspection and 

if required, replacement of the airstair step assembly in accordance with Revision A of 

Bombardier SB 84-52-77, dated 24 April 2013, also satisfies the requirements of Part I of 

this AD. 

Part II – Spares – Applicable to Aeroplane Serial Numbers 4001 and Subsequent: 

As of the effective date of this AD, it is prohibited for anyone to install an airstair step 

assembly part number 85217008-001 containing a S/N in the affected range listed in 

section 1.A. of the above-mentioned SB. 

Authorization: For the Minister of Transport, 

ORIGINAL SIGNED BY 

Robin Lau 

Acting 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.