04-20121. Airworthiness Directives; Saab Model SAAB SF340A and SAAB 340B Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Saab Model SAAB SF340A and SAAB 340B series airplanes. This proposed AD would require an inspection of the elevator and aileron trim-tab fittings, and related investigative/corrective actions if necessary. This proposed AD is prompted by reports of improperly installed rivets in the retainers that hold the elevator trim-tab bearings. We are proposing this AD to prevent the elevator and aileron trim-tab bearings from coming loose, which could result in excessive play in the elevator and aileron trim systems, and reduced controllability of the airplane.

DATES:

We must receive comments on this proposed AD by October 4, 2004.

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.

By 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.

You can get the service information identified in this proposed AD from Saab Aircraft AB, SAAB Aircraft Product Support, S-581.88, Linköping, Sweden.

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov,, or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW, room PL-401, on the plaza level of the Nassif Building, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Technical information: Dan Rodina, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

Plain language information: Marcia Walters, [e-mail].

SUPPLEMENTARY INFORMATION:

Docket Management System (DMS)

The FAA has implemented new procedures for maintaining AD dockets electronically. As of May 17, 2004, new AD actions are posted on DMS and assigned a docket number. We track each action and assign a corresponding directorate identifier. The DMS AD docket number is in the form “Docket No. FAA-2004-99999.” The Transport Airplane Directorate identifier is in the form “Directorate Identifier 2004-NM-999-AD.” Each DMS AD docket also lists the directorate identifier (“Old Docket Number”) as a cross-reference for searching purposes.

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 under ADDRESSES. Include “Docket No. FAA-2004-19001; Directorate Identifier 2004-NM-98-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 submitted 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 our docket 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.

We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications that affect you. You can get more information about plain language at http://www.faa.gov/​language and http://www.plainlanguage.gov.

Examining the Docket

You may examine the AD docket 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 in the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the DMS receives them.

Discussion

The Luftfartsverket (LFV), which is the airworthiness authority for Sweden, notified us that an unsafe condition may exist on certain Saab Model SAAB SF340A and SAAB 340B series airplanes. The LFV advises that it has received reports from operators regarding improperly installed rivets in the retainers located in the elevator trim-tab fittings. The retainers hold the elevator trim-tab bearings. Improperly installed rivets, if not corrected, could result in loose elevator trim-tab bearings, which could result in excessive play in the elevator control system, severe oscillations, and reduced controllability of the airplane.

The aileron trim-tab system is similar in design to the elevator trim-tab system. The aileron trim-tabs may be subject to a similar unsafe condition. If the rivets that hold the retainers for the aileron trim-tab bearings are improperly installed, the aileron trim-tab bearing could become loose. This condition, if not corrected, could result in excessive play in the aileron control system, severe oscillations, and reduced controllability of the airplane. Because of the similar design, the LFV advises that both the elevator and aileron trim-tab fittings be inspected.

Relevant Service Information

Saab has issued Service Bulletin 340-51-025, Revision 01, dated October 21, 2003. The service bulletin describes procedures for visual inspections of the elevator and aileron trim-tab fittings to determine if riveted, greasable bearings are installed, and related investigative and corrective actions. The related investigative and corrective actions include:

• Inspecting for damage and acceptance limits (as specified in the Saab 340 Structural Repair Manual (SRM) 51-40-20, paragraph “Solid Rivet Inspection”) the rivets and retainers that attach the elevator and aileron trim-tabs to the airplane structure.
• Replacing damaged rivets with new rivets and installing new bearings.
• Inspecting the elevator and aileron trim mechanical installations (e.g., pushrods and levers) for damage (as specified in the SRM) and loose fasteners.
• Replacing damaged parts and tightening loose fasteners.
• Inspecting the axial play of the elevator trim-tab bearings.
• Inspecting the axial play of the aileron trim-tab bearings and the movement of the third hinge.
• Doing a backlash inspection after all of the necessary corrective actions have been done.
• Reporting to the manufacturer any major damage found to any retainer.
• Marking the lower right corner of each elevator and aileron trim-tab identification plate with three in-line punch marks.

We have determined that accomplishing the actions specified in the service information will adequately address the unsafe condition. The LFV mandated the service information and issued Swedish airworthiness directive 1-194, dated October 14, 2003, to ensure the continued airworthiness of these airplanes in Sweden.

FAA's Determination and Requirements of the Proposed AD

These airplane models are manufactured in Sweden 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. According to this bilateral airworthiness agreement, the LFV has kept the FAA informed of the situation described above. We have examined the LFV's findings, evaluated all pertinent information, and determined that we need to issue an AD for products of this type design that are certificated for operation in the United States.

Therefore, we are proposing this AD, which would require inspections of the elevator and aileron trim-tab fittings, and related investigative/corrective actions if necessary. The proposed AD would require you to use the service information described previously to perform these actions, except as discussed under “Differences Between the Proposed AD and Service Information.”

Differences Between the Proposed AD and Service Information

Although the Accomplishment Instructions of the referenced service bulletin describe procedures for reporting certain damage to the manufacturer, this proposed AD would not require that action.

The service bulletin specifies to do a “visual inspection” to determine if riveted greasable bearings are installed on the elevator and aileron trim-tab fittings. The service bulletin also specifies to do an “inspection” for damage to the rivets that attach the retainers to the elevator and aileron trim-tab fittings. This proposed AD would require “detailed inspections” for these actions. We have included the definition for a detailed inspection in a note in this proposed AD.

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 hour airplanes	Fleet cost
Inspection	16	$65	None	$1,040	170	$176,800

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. 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 FAA amends § 39.13 by adding the following new airworthiness directive (AD):

Saab Aircraft AB: Docket No. FAA-2004-19001; Directorate Identifier 2004-NM-98-AD.

Comments Due Date

(a) The Federal Aviation Administration must receive comments on this AD action by October 4, 2004.

Affected ADs

(b) None.

Applicability

(c) This AD applies to certain Saab Model SAAB SF340A series airplanes, line numbers 004 through 159 inclusive; and SAAB 340B series airplanes, line numbers 160 through 459 inclusive; certificated in any category.

Unsafe Condition

(d) This AD was prompted by reports of improperly installed rivets in the retainers located in the elevator trim-tab fittings. The retainers hold the trim-tab bearings. We are issuing this AD to prevent the elevator and aileron trim-tab bearings from coming loose, which could result in excessive play in the elevator and aileron trim systems, and 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 Related Investigative/Corrective Actions

(f) Within 800 flight hours or 6 months after the effective date of this AD, whichever is first: Do a detailed inspection of the elevator and aileron trim-tab fittings, and all applicable related investigative and corrective actions, by accomplishing all of the actions in the Accomplishment Instructions of Saab Service Bulletin 340-51-025, Revision 01, dated October 21, 2003. Any related investigative and corrective actions must be done before further flight.

Note 1:

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

Parts Installation

(g) As of the effective date of this AD, no person may install on any airplane an elevator or aileron trim-tab fitting unless it has been inspected, and any applicable corrective actions have been done, in accordance with paragraph (f) of this AD.

Reporting Not Required

(h) Although the service bulletin referenced in this AD specifies to submit certain information to the manufacturer, this AD does not include that requirement.

Alternative Methods of Compliance (AMOCs)

(i) The Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

Related Information

(j) Swedish airworthiness directive 1-194, dated October 14, 2003, also addresses the subject of this AD.

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

Kevin M. Mullin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.