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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)

1/3 No.

CF-2003-23R3

Issue Date 

 21 May 2010 

Number: CF- 2003-23R3 

Subject: Main Landing Gear Door Separation During Flight 

Effective: 9 June 2010 

Revision: Supersedes Airworthiness Directive (AD) CF-2003-23R2 issued on 27 July 2005

Applicability: Bombardier CL-600-2C10 Serial Number 10003 through 10230, CL-600-2D15 and 

CL-600-2D24 Serial Number 15001 through 15053, 15055, and 15056.

Compliance: As indicated below unless already accomplished. 

Background: The right-hand inboard main landing gear (MLG) door of a CRJ 700 departed the aircraft 

during the landing phase of flight. The door damaged the trailing edge flap and punctured 

the rear fuselage near the floor level. The aircraft landed safely. Preliminary investigation 

indicates the failure was initiated by fatigue of the panel structure near a panel hinge lug. 

Loss of the main landing gear door during flight could result in damage to the aircraft and 

injury to persons on the ground. 

Subsequent to the issuance of Revision 1 of this directive, Transport Canada (TC) 

approved an alternate means of compliance (AMOC), AARDG 2004/A007, to allow 

extension of the repeat inspection interval when inboard MLG doors have incorporated 

certain repairs or modifications. 

Subsequent to the issuance of the TC AMOC AARDG 2004/A007, an inboard MLG door 

departed from an aircraft operating under an AMOC equivalent to TC AMOC AARDG 

2004/007. As a result of this incident, this directive was revised to Revision 2 to introduce 

additional inspection requirements according to Bombardier Alert Service Bulletin 

A670-32-016. In addition, Revision 2 also eliminated escalation of the repeat inspection 

interval allowed in TC AMOC AARDG 2004/007 and revised the aircraft applicability to 

add a new aircraft model. 

Since the issuance of Revision 2 of this directive, TC approved an AMOC, AARDG 

2006-A051, to allow the installation of a new modified MLG door configuration and to 

perform alternative inspection. Service history shows that this new modified MLG door 

configuration resolves the safety concerns associated with this directive. 

Revision 3 of this directive mandates the incorporation of the new modified MLG door 

configuration in accordance with Bombardier Aerospace Service Bulletin (SB)

670BA-32-017 as the terminating action. In addition, this revision restricts the applicability 

to aircraft not equipped with the new modified MLG door configuration at delivery. 
No.

 N° CF-2003-23R3 2/3 

Corrective 

Actions: 

Initial Inspection 

Applicable for aircraft that have not carried out the initial inspection mandated in the 

original issue, Revision 1, or Revision 2 of this directive. 

1. Using the following schedule, inspect both left hand (L/H) and right hand (R/H) 

inboard MLG doors for damages, in accordance with Part A of the Accomplishment 

Instructions of Bombardier Alert Service Bulletin (ASB) A670-32-016, Revision A, 

dated 7 June 2005, or later revisions approved by the Chief, Continuing 

Airworthiness, Transport Canada: 

(a) For aircraft that have accumulated 1500 flight cycles or more at the effective date 

of this directive, before accumulating an additional 10 flight cycles; 

(b) For aircraft that have accumulated more than 1000 flight cycles but less than 

1500 flight cycles at the effective date of this directive, before accumulating an 

additional 50 flight cycles; and 

(c) For aircraft that have accumulated 1000 flight cycles or less at the effective date 

of this directive, before the aircraft reach 1050 flight cycles. 

2. If damage to any inboard MLG door is found, before further flight comply with one of 

the following options: 

(a) Replace the damaged inboard MLG door(s) with new or repaired door(s) in 

accordance with Part B of the Accomplishment Instructions of Bombardier Alert 

Service Bulletin (ASB) A670-32-016, Revision A, dated 7 June 2005, or later 

revisions approved by the Chief, Continuing Airworthiness, Transport Canada; or 

(b) Remove the damaged inboard MLG door(s) and return the aircraft to service 

under the limitations specified in Appendix 1 - Configuration Deviation List (CDL) 

of the applicable Airplane Flight Manual, CSP B-012 or CSP C-012. 

Repeat Inspections 

3. Aircraft returned to service following the initial inspection of this directive, or previous 

versions of this directive, are to have the inboard MLG doors re-inspected in 

accordance with paragraphs 1 and 2 of this directive, at intervals not exceeding 

100 flight cycles. 

4. For aircraft that have increased the repeat inspection interval to 450 flight cycles 

through an AMOC, phase in the next repeat inspection in accordance with the 

following schedule and thereafter perform the repeat inspections at intervals not 

exceeding 100 flight cycles: 

(a) For aircraft that have accumulated less than 50 flight cycles since the last 

inspection, prior to the aircraft accumulating 100 flight cycles since the last 

inspection. 

(b) For aircraft that have accumulated more than or equal to 50 flight cycles but less 

than 400 flight cycles since the last inspection, prior to the aircraft accumulating 

an additional 50 flight cycles. 

(c) For aircraft that have accumulated 400 flight cycles or more since the last 

inspection, prior to the aircraft accumulating 450 flight cycles since the last 

inspection. 
No.

 N° CF-2003-23R3 3/3 

Reporting Requirements 

5. Within five days of completing each inspection, report any damages found to 

Bombardier. 

Modify MLG Door Configuration 

6. Within 6000 hours air time after the effective date of this directive, modify the MLG 

door configuration in accordance with the Accomplishment Instructions of Bombardier 

Aerospace SB 670BA-32-017, Revision C, dated 14 May 2010, or later revisions 

approved by the Chief, Continuing Airworthiness, Transport Canada. 

Note: Modification in accordance with earlier versions of Bombardier Aerospace SB 

670BA-32-017 meets the requirements of paragraph 6 of this directive. 

7. Incorporation of the modified MLG door configuration provides terminating action to 

this directive. 

Authorization: For Minister of Transport, Infrastructure and Communities 

ORIGINAL SIGNED BY

Derek Ferguson 

Chief, Continuing Airworthiness 

Contact: Miss Helen Tsai, Continuing Airworthiness, Ottawa, telephone 613-952-4357, facsimile 

613-996-9178 or e-mail CAWWEBFeedback@tc.gc.ca or any Transport Canada Centre.