E6-8898. Airworthiness Directives; Bombardier Model DHC-8-100, DHC-8-200, DHC-8-300, and DHC-8-400 Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Bombardier Model DHC-8-100, DHC-8-200, DHC-8-300, and DHC-8-400 series airplanes. This proposed AD would require inspecting the left and right control column torque tube assemblies to determine the type of rivets installed and replacing incorrect or indeterminate type rivets with the correct type rivets. This proposed AD results from a report that incorrect rivets having lower than required strength were installed on the control column torque tube during production. We are proposing this AD to prevent shear failure of control column torque tube rivets, which could cause unexpected decoupling of the elevators and large unwanted deflection of the free elevator, and consequent reduced controllability of the airplane.

DATES:

We must receive comments on this proposed AD by July 10, 2006.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, room PL-401, Washington, DC 20590.
• Fax: [phone].
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Bombardier, Inc., Bombardier Regional Aircraft Division, 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada, for service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Richard Beckwith, Aerospace Engineer, Airframe and Propulsion Branch, ANE-171, FAA, New York Aircraft Certification Office, 1600 Stewart Avenue, suite 410, Westbury, New York 11590; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “FAA-2006-24979; Directorate Identifier 2006-NM-014-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Docket

You may examine the AD docket on the Internet at http://dms.dot.gov,, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Discussion

Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, notified us that an unsafe condition may exist on certain Bombardier DHC-8-100, DHC-8-200, DHC-8-300, and DHC-8-400 series airplanes. TCCA advises that incorrect rivets having lower than required strength were installed on the control column torque tube during production. This condition, if not corrected, could result in shear failure of rivets in the control column torque tube during a jam of the pitch control circuit, when the pilot of the non-jammed pitch control tries to free the control by applying a large force. This type of rivet failure could cause unexpected decoupling of the elevators and large unwanted deflection of the free elevator, reducing the controllability of the airplane.

Relevant Service Information

Bombardier has issued Service Bulletin 8-27-104, dated October 26, 2004, for Model DHC-8-100, DHC-8-200, and DHC-8-300 series airplanes, and Service Bulletin 84-27-24, Revision A, dated September 28, 2005, for Model DHC-8-400 series airplanes. The service bulletins describe procedures for inspecting the left and right control column torque tube assemblies to determine the type of rivets installed and replacing incorrect (AD rivets) or indeterminate type rivets with the correct type rivets (DD or DN rivets). Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. TCCA mandated the service information and issued Canadian airworthiness directive CF-2005-39, dated November 21, 2005, to ensure the continued airworthiness of these airplanes in Canada.

FAA's Determination and Requirements of the Proposed AD

These airplane models are manufactured in Canada and are type certificated for operation in the United States under the provisions of section 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 the FAA informed of the situation described above. We have examined TCCA's findings, evaluated all pertinent information, and determined that we need to issue an AD for airplanes of this type design that are certificated for operation in the United States.

Therefore, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the Proposed AD and the Service Information.”

Differences Between the Proposed AD and the Service Information

Bombardier Service Bulletin 8-27-104 and Service Bulletin 84-27-24, Revision A, specify replacing incorrect or unidentifiable rivets with DN rivets. This proposed AD allows replacement with either DN or DD rivets. The service bulletins state no further action is necessary if DD rivets are found installed; this proposed AD does not require replacement of the rivets if either DN or DD rivets are found installed.

Clarification of Inspection Terminology

The service bulletin refers only to an “inspection” for the type of rivets installed. We have determined that the procedures in the service bulletin should be described as a “general visual inspection.” Note 1 has been included in this AD to define this type of inspection.

Costs of Compliance

The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Inspection for rivet type	1	$80	$0	$80	162	$12,960.
Rivet replacement, if necessary	16	80	50	1,330	162	A maximum of $215,460.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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.

For the reasons discussed above, I certify that the proposed regulation:

1. Is not a “significant regulatory action” under Executive Order 12866;

2. Is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and

3. Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

Bombardier, Inc. (Formerly de Havilland, Inc.): Docket No. FAA-2006-24979; Directorate Identifier 2006-NM-014-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by July 10, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Bombardier airplanes identified in Table 1 of this AD, certified in any category.

Table 1.—Applicability

Bombardier airplane model—	Affected serial numbers (S/N)—
(1) DHC-8-102, DHC-8-103, DHC-8-106, DHC-8-201, DHC-8-202, DHC-8-301, DHC-8-311, DHC-8-314, and DHC-8-315 airplanes	528 through 602 inclusive, and 606.
(2) DHC-8-400, DHC-8-401, and DHC-8-402 airplanes	4003, 4004, 4006, 4008 through 4080 inclusive, and 4082.

Unsafe Condition

(d) This AD results from a report that incorrect rivets having lower than required strength were installed on the control column torque tube during production. We are issuing this AD to prevent shear failure of rivets in the control column torque tube, which could cause unexpected decoupling of the elevators and large unwanted deflection of the free elevator, and consequent reduced controllability of the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Inspection and Replacement of Incorrect Rivets

(f) At the applicable times specified in Table 2 of this AD: Do the applicable actions in accordance with the applicable service bulletin identified in Table 2 of this AD. If all rivets identified during the inspection specified in paragraphs (f)(1)(i) or (f)(2)(i) of this AD are of the correct type (DD or DN rivets), no further action is required by this AD.

Note 1:

For the purposes of this AD, a general visual inspection is: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

Table 2.—Inspection and Replacement of Incorrect Rivets

Model—	Compliance time—	Action—	In accordance with—
(1) Model DHC-8-102, DHC-8-103, DHC-8-106, DHC-8-201, DHC-8-202, DHC-8-301, DHC-8-311, DHC-8-314, and DHC-8-315 airplanes	(i) Within 5,500 flight hours after the effective date of this AD	Do a general visual inspection of the left and right control column torque tube assemblies to determine the types of rivets installed	Part A of the Accomplishment Instructions of Bombardier Service Bulletin 8-27-104, dated October 26, 2004.
	(ii) Before further flight	Replace any rivet of an incorrect type (AD rivets) or of a type that cannot be determined with correct type rivets (DD or DN rivets)	Part B of the Accomplishment Instructions of Bombardier Service Bulletin 8-27-104, dated October 26, 2004.
(2) Model DHC-8-400, DHC-8-401, and DHC-8-402 airplanes	(i) Within 5,500 flight hours after the effective date of the AD	Do a general visual inspection of the left and right control column torque tube assemblies to determine the type of rivets installed	Part A of the Accomplishment Instructions of Bombardier Service Bulletin 84-27-24, Revision A, dated September 28, 2005.
	(ii) Before further flight	Replace any rivet of an incorrect type (AD rivets) or of a type that cannot be determined with correct type rivets (DD or DN rivets)	Part B of the Accomplishment Instructions of Bombardier Service Bulletin 84-27-24, Revision A, dated September 28, 2005.

Actions Accomplished According to Previous Issue of Service Bulletin

(g) For Model DHC-8-400, DHC-8-401 and DHC-8-402 airplanes: Inspections and rivet replacements done before the effective date of this AD according to Bombardier Service Bulletin 84-27-24, dated September 20, 2004, are considered acceptable for compliance with the corresponding actions specified in this AD.

Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, New York Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Related Information

(i) Canadian airworthiness directive CF-2005-39, dated November 21, 2005, also addresses the subject of this AD.

Issued in Renton, Washington, on May 31, 2006.

Jeffrey E. Duven,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.