E6-8008. Airworthiness Directives; Bombardier Model DHC-8-102, -103, and -106 Airplanes, and DHC-8-200 and DHC-8-300 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-8-102, -103, and -106 airplanes, and DHC-8-200 and DHC-8-300 series airplanes. This proposed AD would require performing a one-time inspection for non-conforming chain links of chain assemblies of the elevator trim system and gust lock system, and corrective actions if necessary. This proposed AD would also require temporary revisions to the airplane flight manuals of the affected airplanes, which describe procedures for elevator trim checks. This proposed AD results from several reports of failure of the elevator trim chain, due to hydrogen embrittlement. We are proposing this AD to prevent breakage of the elevator trim chain, which would prevent the actual position of the elevator trim tab from being annunciated to the flightcrew. Attempting to adjust the trim tab to the full nose up or full nose down position with a broken trim chain could cause reduced control during airplane rotation on the ground or a stall during flight.

DATES:

We must receive comments on this proposed AD by June 26, 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:

Ezra Sasson, Aerospace Engineer, Systems and Flight Test Branch, ANE-172, 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-2006-24867; Directorate Identifier 2006-NM-064-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 Model DHC-8-102, -103, and -106 airplanes, and DHC-8-200 and DHC-8-300 series airplanes. TCCA has received reports of several failures of the elevator trim chain, due to cracking of certain chain links caused by hydrogen embrittlement. This condition, if not corrected, could result in breakage of the elevator trim chain, which would prevent the actual position of the elevator trim tab from being annunciated to the flightcrew. Attempting to adjust the trim tab to the full nose up or full nose down position with a broken trim chain could cause reduced control during airplane rotation on the ground or a stall during flight.

Relevant Service Information

Bombardier has issued temporary amendments (TA) to the product support manuals (PSM) of the airplane flight manuals (AFM) of the affected airplanes, as shown in the following table. The TAs describe procedures for visual trim checks to verify that elevators are in acceptable positions relative to elevator trim wheel settings. Operators should note that the suffixes “NS,” “S,” and “HT,” only appear on the labels of certain AFMs and do not indicate separate airplane models. For example, a Model 102NS airplane is a Model 102 airplane.

Temporary Amendments (TAs)

Airplane model/AFM No.	PSM	TA No.	Effective date
102, 103, and 106	1-81-1A	9	January 28, 2004.
102NS, 103NS, and 106NS	1-81-1A	8	January 28, 2004.
201	1-82-1A	11	June 22, 2005.
202	1-82-1A	10	January 28, 2004.
201S and 202S	1-82-1A	9	June 22, 2005.
202HT	1-82-1A	8	January 28, 2004.
301	1-83-1A	8	January 28, 2004.
311	1-83-1A	15	January 28, 2004.
315	1-83-1A	9	January 28, 2004.

Bombardier has issued Service Bulletin 8-27-105, Revision ‘A,’ dated September 13, 2005. The service bulletin describes procedures for performing a one-time inspection for non-conforming chain links of chain assemblies of the elevator trim system and gust lock system, and corrective actions if necessary. Conforming chain links are identified with the number RC-25; non-conforming chain links are identified with other numbers. Corrective actions include replacing any non-conforming chain links with conforming chain links, or replacing the trim chain/chain assembly with a new or serviceable trim chain/chain assembly.

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-2005-38, dated October 25, 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.

Costs of Compliance

This proposed AD would affect about 166 airplanes of U.S. registry. The proposed inspection would take about 5 work hours per airplane, at an average labor rate of $80 per work hour. Based on these figures, the estimated cost of the proposed inspection for U.S. operators is $66,400, or $400 per airplane.

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-2006-24867; Directorate Identifier 2006-NM-064-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by June 26, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Bombardier Model DHC-8-102, -103, and -106 airplanes, and DHC-8-200 and DHC-8-300 series airplanes, certificated in any category; as identified in Bombardier Service Bulletin 8-27-105, Revision ‘A,’ dated September 13, 2005.

Unsafe Condition

(d) This AD results from reports of several failures of the elevator trim chain, due to hydrogen embrittlement. We are issuing this AD to prevent breakage of the elevator trim chain, which would prevent the actual position of the elevator trim tab from being annunciated to the flightcrew. Attempting to adjust the trim tab to the full nose up or full nose down position with a broken trim chain could cause reduced control during airplane rotation on the ground or a stall during flight.

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.

Temporary Amendments (TAs)

(f) Within 30 days after the effective date of this AD, revise the applicable airplane flight manual (AFM) of the affected airplanes by incorporating the information in the TAs into the product support manuals (PSM) listed in Table 1 of this AD. This may be accomplished by inserting a copy of the applicable TA into the AFM. The copy of the TA may be removed from the AFM when a new revision of the AFM is released that incorporates material identical to the content of the TA.

Table 1.—Bombardier Temporary Amendments (TAs)

Airplane model/AFM No.	PSM	TA No.	Effective date
102, 103, and 106	1-81-1A	9	January 28, 2004.
102NS, 103NS, and 106NS	1-81-1A	8	January 28, 2004.
201	1-82-1A	11	June 22, 2005.
202	1-82-1A	10	January 28, 2004.
201S and 202S	1-82-1A	9	June 22, 2005.
202HT	1-82-1A	8	January 28, 2004.
301	1-83-1A	8	January 28, 2004.
311	1-83-1A	15	January 28, 2004.
315	1-83-1A	9	January 28, 2004.

Note 1:

The suffixes “NS,” “S,” and “HT,” do not indicate separate airplane models; for example, a Model 102NS airplane is a Model 102 airplane.

Inspection and Corrective Actions

(g) Within 6,000 flight hours or 36 months after the effective date of this AD, whichever occurs first, perform a one-time general visual inspection for non-conforming chain links of the trim chain/chain assemblies of the elevator trim system and gust lock system and, before further flight, do applicable corrective actions, in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 8-27-105, Revision ‘A,’ dated September 13, 2005. After accomplishing the requirements of this paragraph, operators may remove the AFM revisions required by paragraph (f) of this AD from the AFM.

Parts Installation

(h) As of the effective date of this AD, no person may install an elevator trim chain/chain assembly on any airplane, unless the chain links of that trim chain/chain assembly are identified with the number RC-25.

Alternative Methods of Compliance (AMOCs)

(i)(1) The Manager, New York Aircraft Certification Office, 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

(j) Canadian airworthiness directive CF-2005-38, dated October 25, 2005, also addresses the subject of this AD.

Issued in Renton, Washington, on May 17, 2006.

Kevin M. Mullin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.