04-4683. Airworthiness Directives; Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

This amendment adopts a new airworthiness directive (AD) that is applicable to all Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. This action requires repetitive inspections of the left and right engine throttle control gearboxes for wear, and corrective action if necessary. This action is necessary to prevent excessive wear of the gearboxes and subsequent movement or jamming of the engine throttle; movement of the throttle towards the idle position brings it close to the fuel shut-off switch, which could result in an in-flight engine shutdown. This action is intended to address the identified unsafe condition.

DATES:

Effective March 25, 2004.

The incorporation by reference of a certain publication listed in the regulations is approved by the Director of the Federal Register as of March 25, 2004.

Comments for inclusion in the Rules Docket must be received on or before April 9, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2004-NM-20-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via the Internet must contain “Docket No. 2004-NM-20-AD” in the subject line and need not be submitted in triplicate. Comments sent via fax or the Internet as attached electronic files must be formatted in Microsoft Word 97 or 2000 or ASCII text.

The service information referenced in this AD may be obtained from Bombardier, Inc., Canadair, Aerospace Group, P.O. Box 6087, Station Centreville, Montreal, Quebec H3C 3G9, Canada. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, New York Aircraft Certification Office, 1600 Stewart Avenue, Westbury, New York; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

James Delisio, Aerospace Engineer, Airframe and Propulsion Branch, ANE-171, FAA, New York Aircraft Certification Office, 1600 Stewart Avenue, Westbury, New York 11581; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, notified the FAA that an unsafe condition may exist on all Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. TCCA advises that there have been numerous failures of the engine throttle control gearbox; some of the failures resulted in an in-flight engine shutdown. Investigation revealed that when the throttle is in the climb/cruise position, the rack teeth inside the gearbox can become worn down. Such excessive wear of the engine throttle gearbox can alter the rigging position or cause the throttle to jam. Movement of the throttle towards the idle position brings it close to the fuel shut-off switch, which can cause the engine to flame out. This condition, if not corrected, could result in an in-flight engine shutdown.

Explanation of Relevant Service Information

Bombardier has issued Service Bulletin 601R-76-019, dated August 21, 2003, which describes procedures for inspections of the left and right engine throttle control gearboxes for certain wear values, and corrective action if necessary, as specified below:

• If the wear value is equal to or less than 0.006 inch (0.152 mm) on both gearboxes, no corrective action is necessary.
• If the wear value is 0.010 inch (0.254 mm) or greater on one or both engine throttle gearboxes, the service bulletin describes procedures for replacing the affected gearbox with a new or serviceable gearbox before further flight.
• If the wear values are between 0.006 inch (0.152 mm) and 0.010 inch (0.254 mm) on both engine throttle gearboxes, the service bulletin describes procedures for replacing the gearbox having the higher wear value with a new or serviceable gearbox before further flight, and replacing the gearbox having the lower wear value with a new or serviceable gearbox within the next 1,000 flight hours.
• If the wear values are between 0.006 inch (0.152 mm) and 0.010 inch (0.254 mm), on one engine throttle gearbox only, and the wear value on the other gearbox is equal to or less than 0.006 inch (0.152mm), the service bulletin describes procedures for replacing the affected gearbox (having wear values between 0.006 inch and 0.010 inch) with a new or serviceable gearbox within the next 1,000 flight hours.

All of the corrective actions specified above include rigging of the auto-throttle retarder control, and doing a functional test of the throttle system.

The service bulletin also recommends that, during the inspection, operators make sure that the bolt and the two screws on the throttle control rod are correctly torqued to 20-25 lbf-in (2.25-2.82 N m). If the torque is not correct, the service bulletin specifies tightening to the correct torque and sending a report of the wear value on the gearbox to Bombardier. Accomplishment of the actions specified in the Bombardier service bulletin is intended to adequately address the identified unsafe condition.

The Bombardier service bulletin references Trans Digm Inc., AeroControlex Group Service Bulletin 2100140-007-76-04, dated July 22, 2003, as an additional source of service information for accomplishment of the inspections and replacement.

TCCA classified the Bombardier service bulletin as mandatory and issued Canadian airworthiness directive CF-2004-01, dated January 21, 2004, to ensure the continued airworthiness of these airplanes in Canada.

FAA's Conclusions

These airplane models are manufactured in Canada and are type certificated for operation in the United States under the provisions of § 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, TCCA has kept us informed of the situation described above. We have examined the findings of TCCA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Explanation of Requirements of Rule

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, this AD is being issued to prevent failure of the engine throttle control gearboxes, which could result in an in-flight engine shutdown. This AD requires repetitive inspections of the left and right engine throttle control gearboxes for wear, and corrective action if necessary. This AD also includes a reporting requirement. The actions are required to be accomplished in accordance with the service bulletin described previously, except as discussed below.

This AD allows flight with wear on one engine throttle gearbox, provided that (1) the wear value meets the specifications in Part A, paragraph B.(7), of the Accomplishment Instructions of the Bombardier service bulletin, and (2) established inspection procedures detect wear values at intervals permitting replacement of the engine throttle control gearbox before the gearbox exceeds the acceptable wear value.

Differences Among Canadian Airworthiness Directive, Bombardier Service Bulletin, and This AD

The Canadian airworthiness directive and the service bulletin specify the applicability as Model CL-600-2B19 airplanes with serial numbers 7003 through 7067 inclusive, and 7069 through 7999 inclusive. However, we have determined that all Model CL-600-2B19 may be subject to the identified unsafe condition; therefore, this AD is applicable to “All Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes, certificated in any category.”

Although the service bulletin recommends returning discrepant gearboxes to the parts manufacturer, this AD does not contain such a requirement.

The Canadian airworthiness directive and the service bulletin do not define the type of inspection for wear of the engine throttle control gearboxes. We have clarified the inspection requirement contained in the AD as a detailed inspection. A note has been added to the AD to define that inspection.

The Canadian airworthiness directive and the service bulletin recommend accomplishing the initial inspection of the engine throttle control gearboxes within 1,000 flight hours, but this AD requires accomplishment within 1,000 flight hours or 90 days, whichever is first. We find that a compliance time of 1,000 flight hours might not provide enough time to maintain an adequate level of safety for the affected fleet for those operators having airplanes with a high number of flight hours every day. In developing an appropriate compliance time for this AD, we considered the degree of urgency associated with addressing the unsafe condition, and the maximum interval of time allowable for all affected airplanes to continue to operate without compromising safety. We find the specified compliance time to be appropriate for completing the initial inspection.

Interim Action

This AD is considered to be interim action. The reports that are required by this AD will enable the manufacturer to obtain better insight into the nature, cause, and extent of the wear of the engine throttle control gearbox, and eventually to develop final action to address the unsafe condition. Once final action has been identified, we may consider further rulemaking.

Determination of Rule's Effective Date

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited

Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption ADDRESSES. All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the AD is being requested.
• Include justification (e.g., reasons or data) for each request.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2004-NM-20-AD.” The postcard will be date stamped and returned to the commenter.

Regulatory Impact

The regulations adopted herein will not have a substantial direct effect on the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a “significant regulatory action” under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13

[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

2004-05-12 Bombardier, Inc. (Formerly Canadair): Amendment 39-13507. Docket 2004-NM-20-AD.

Applicability: All Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent excessive wear of the gearboxes and subsequent movement or jamming of the engine throttle; movement of the throttle towards the idle position brings it close to the fuel shut-off switch, which could result in an in-flight engine shutdown, accomplish the following:

Repetitive Inspections

(a) Within 1,000 flight hours or 90 days after the effective date of this AD, whichever is first: Do a detailed inspection of the left and right engine throttle control gearboxes for wear by doing all the actions per Part A, paragraphs A., B., and C.(1) through C.(4), of the Accomplishment Instructions of Bombardier Service Bulletin 601R-76-019, dated August 21, 2003. If the wear value is the same as that specified in Part A, paragraph B.(8), of the Accomplishment Instructions of the service bulletin, repeat the inspection thereafter at intervals not to exceed 1,000 flight hours.

Note 1:

For the purposes of this AD, a detailed inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”

Corrective Action

(b) If the wear value found during any inspection required by paragraph (a) of this AD is not the same as that specified Part A, paragraph B.(8), of the Accomplishment Instructions of Bombardier Service Bulletin 601R-76-019, dated August 21, 2003: Do the applicable actions required by paragraph (b)(1), (b)(2), or (b)(3) of this AD, at the time specified, per the Accomplishment Instructions of the service bulletin. Repeat the inspection required by paragraph (a) of this AD thereafter at intervals not to exceed 1,000 flight hours.

(1) If the wear value on one or both of the gearboxes is the same as that specified in Part A, paragraph B.(5), of the Accomplishment Instructions of the service bulletin: Before further flight, replace the affected gearbox with a new or serviceable gearbox, by doing all the actions per Part B, paragraphs D. through F.(7), of the Accomplishment Instructions of the service bulletin.

(2) If the wear value on both the left and right gearboxes is the same as that specified in Part A, paragraph B.(6), of the Accomplishment Instructions of the service bulletin: Before further flight, replace the gearbox having the higher wear value with a new or serviceable gearbox, by doing all the actions per Part B, paragraphs D. through F.(7), of the Accomplishment Instructions of the service bulletin. Within 1,000 flight hours after doing the replacement, replace the other gearbox.

(3) If the wear value on only one gearbox is the same as that specified in Part A, paragraph B.(7), and the wear value on the other gearbox is the same as that specified in Part A, paragraph B.(8), of the Accomplishment Instructions of the service bulletin: Within 1,000 flight hours after the inspection, replace the gearbox with the wear value that is the same as that specified in Part A, paragraph B.(7), with a new or serviceable gearbox. Do the replacement by doing all the actions per Part B, paragraphs D. through F.(7), of the Accomplishment Instructions of the service bulletin.

Additional Service Information

Note 2:

Bombardier Service Bulletin 601R-76-019, dated August 21, 2003, references Trans Digm Inc., AeroControlex Group Service Bulletin 2100140-007-76-04, dated July 22, 2003, as an additional source of service information for accomplishment of the inspections and replacement.

Reporting Requirement

(c) Within 10 days after accomplishment of the inspection required by paragraph (a) of this AD, or within 10 days after the effective date of this AD, whichever is later: Submit a report of gearbox wear to Bombardier Aerospace, as specified in Part A, paragraph B.(1), and Part B, paragraph E.(1) of the Accomplishment Instructions of Bombardier Service Bulletin 601R-76-019, dated August 21, 2003.

Alternative Methods of Compliance

(d) In accordance with 14 CFR 39.19, the Manager, New York Aircraft Certification Office, is authorized to approve alternative methods of compliance for this AD.

Incorporation by Reference

(e) The actions shall be done in accordance with Bombardier Service Bulletin 601R-76-019, dated August 21, 2003. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Bombardier, Inc., Canadair, Aerospace Group, P.O. Box 6087, Station Centreville, Montreal, Quebec H3C 3G9, Canada. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, New York Aircraft Certification Office, 1600 Stewart Avenue, Westbury, New York; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Note 3:

The subject of this AD is addressed in Canadian airworthiness directive CF-2004-01, dated January 21, 2004.

Effective Date

(f) This amendment becomes effective on March 25, 2004.

Issued in Renton, Washington, on February 25, 2004.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.