E6-10537. Airworthiness Directives; Saab Model SAAB-Fairchild SF340A (SAAB/SF340A) and SAAB 340B Airplanes

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to certain Model SAAB-Fairchild SF340A and SAAB 340B airplanes. The existing AD currently requires repetitive inspections for wear of the brushes and leads and for loose rivets of the direct current (DC) starter generator, and related investigative/corrective actions if necessary. This proposed AD would require installing new improved generator control units (GCUs). Installing the GCUs would end the repetitive inspection requirements of the existing AD. This proposed AD results from reports of premature failures of the DC starter generator prior to scheduled overhaul. We are proposing this AD to prevent failure of the starter generator, which could cause a low voltage situation in flight and result in increased pilot workload and reduced redundancy of the electrical powered systems.

DATES:

We must receive comments on this proposed AD by August 7, 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 Saab Aircraft AB, SAAB Aircraft Product Support, S-581.88, Linkoping, Sweden, for service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Mike Borfitz, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; 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 “Docket No. FAA-2006-25271; Directorate Identifier 2006-NM-067-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

On February 11, 2005, we issued AD 2005-04-12, amendment 39-13984 (70 FR 9215, February 25, 2005), for certain Saab Model SAAB SF340A and SAAB 340B series airplanes. That AD requires repetitive inspections for wear of the brushes and leads and for loose rivets of the direct current (DC) starter generator, and related investigative/corrective actions if necessary. That AD resulted from reports of premature failures of the DC starter generator prior to scheduled overhaul. We issued that AD to prevent failure of the starter generator, which could cause a low voltage situation in flight and result in increased pilot workload and reduced redundancy of the electrical powered systems.

Actions Since Existing AD Was Issued

The preamble to AD 2005-04-12 explains that we considered the requirements “interim action” and were considering further rulemaking if a final action is identified. The manufacturer has now designed a new improved generator control unit (GCU), and we have determined that further rulemaking is indeed necessary; this proposed AD follows from that determination.

Relevant Service Information

Saab has issued Saab 340 Service Bulletin 340-24-026, Revision 03, dated December 20, 2004. The service bulletin describes procedures for installing new improved GCUs. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. The Luftfartsverket (LFS), which is the airworthiness authority for Sweden, mandated the service information and issued Swedish airworthiness directive 1-197, dated November 5, 2004, 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. Pursuant to this bilateral airworthiness agreement, the LFS has kept the FAA informed of the situation described above. We have examined the LFS's findings, evaluated all pertinent information, and determined that AD action is necessary for airplanes of this type design that are certificated for operation in the United States. This proposed AD would supersede AD 2005-04-12 and would continue to require repetitive inspections for wear of the brushes and leads and for loose rivets of the direct current (DC) starter generator, and related investigative/corrective actions if necessary. This proposed AD would also require installing new improved GCUs. Installing the GCUs would end the repetitive inspection requirements of AD 2005-04-12.

Changes to Existing AD

This proposed AD would retain all requirements of AD 2005-04-12. Since AD 2005-04-12 was issued, the AD format has been revised, and certain paragraphs have been rearranged. As a result, the corresponding paragraph identifiers have changed in this proposed AD, as listed in the following table:

Revised Paragraph Identifiers

Requirement in AD 2005-04-12	Corresponding requirement in this proposed AD
paragraph (e)	paragraph (f).
paragraph (f)	paragraph (g).
paragraph (g)	paragraph (h).

We have revised the applicability to identify model designations as published in the most recent type certificate data sheet for the affected models.

We have also revised this action to clarify the appropriate procedure for notifying the principal inspector before using any approved AMOC on any airplane to which the AMOC applies.

For clarification, we have revised the definition of a “general visual inspection” in Note 1 of this proposed AD.

Explanation of Change to Costs of Compliance

After AD 2005-04-12 was issued, we reviewed the figures we have used over the past several years to calculate AD costs to operators. To account for various inflationary costs in the airline industry, we find it necessary to increase the labor rate used in these calculations from $65 per work hour to $80 per work hour. The cost impact information, below, reflects this increase in the specified hourly labor rate.

Costs of Compliance

This proposed AD would affect about 170 airplanes of U.S. registry. 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	Fleet cost
Inspections (required by AD 2005-04-02)	1	$80	$0	$80, per inspection cycle	$13,600, per inspection cycle.
Installation (new proposed action)	1	80	7,598	7,678	$1,305,260.

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 removing amendment 39-13984 (70 FR 9215, February 25, 2005) and adding the following new airworthiness directive (AD):

SAAB Aircraft AB: Docket No. FAA-2006-25271; Directorate Identifier 2006-NM-067-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by August 7, 2006.

Affected ADs

(b) This AD supersedes AD 2005-04-12.

Applicability

(c) This AD applies to Saab Model SAAB-Fairchild SF340A (SAAB/SF340A) airplanes having serial numbers 004 through 159 inclusive, and Model SAAB 340B airplanes having serial numbers 160 through 367 inclusive; certificated in any category; on which Saab Modification 2533 has not been implemented.

Unsafe Condition

(d) This AD results from reports of premature failures of the direct current (DC) starter generator prior to scheduled overhaul. We are issuing this AD to prevent failure of the starter generator, which could cause a low voltage situation in flight and result in increased pilot workload and reduced redundancy of the electrical powered systems.

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.

Restatement of the Requirements of AD 2005-04-12

Inspections for Wear of the DC Starter Generator Brushes and Leads

(f) For generators overhauled in accordance with Maintenance Review Board (MRB) Task 243104: Before 800 flight hours since last overhaul, or within 100 flight hours after April 1, 2005 (the effective date of AD 2005-04-12), perform a general visual inspection for wear of the DC starter generator brushes and leads, in accordance with Saab Service Bulletin 340-24-035, dated July 5, 2004.

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.”

Note 2:

Saab Service Bulletin 340-24-035, dated July 5, 2004, references Goodrich Service Information Letter 23080-03X-24-01, dated July 1, 2004, as an additional source of service information.

(1) If the tops of the brush sets are above the top of the brush box, repeat the inspection thereafter at intervals not to exceed 800 flight hours until paragraph (i) of this AD is done.

(2) If the tops of the brush sets are below the top of the brush box, before further flight, measure the brushes and determine the remaining amount of brush life remaining, in accordance with the service bulletin.

(i) If the brush wear is within the limits specified in the service bulletin, repeat the inspection thereafter at intervals not to exceed 800 flight hours until paragraph (i) of this AD is done.

(ii) If the brush wear is outside the limits specified in the service bulletin, before further flight, replace the starter generator with a new or serviceable starter generator, in accordance with the service bulletin.

Inspections for Loose Rivets

(g) For generators overhauled in accordance with MRB Task 243104: Before 800 flight hours since last overhaul, or within 100 flight hours after April 1, 2005, whichever occurs later, perform a general visual inspection of each leading wafer brush for loose rivets, in accordance with Saab Service Bulletin 340-24-035, dated July 5, 2004. Repeat the inspection thereafter at intervals not to exceed 800 flight hours until paragraph (i) of this AD is done. If any rivet is loose, before further flight, replace the DC starter generator with a new or serviceable starter generator, in accordance with the service bulletin.

MRB Task 243103 or 243101

(h) For generators overhauled or with brush replacement accomplished in accordance with MRB Task 243103 or 243101, no action is required by paragraphs (f) and (g) of this AD.

New Requirements of This AD

Installation

(i) For all generators: Within 36 months after the effective date of this AD, install new improved generator control units (GCUs) in accordance with the Accomplishment Instructions of Saab Service Bulletin 340-24-026, Revision 03, dated December 20, 2004. Installing the GCUs terminates the repetitive inspection requirements of paragraphs (f) and (g) of this AD.

Alternative Methods of Compliance (AMOCs)

(j)(1) The Manager, International Branch, ANM-116, Transport Airplane Directorate, 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

(k) Swedish airworthiness directive 1-197, dated November 5, 2004, also addresses the subject of this AD.

Issued in Renton, Washington, on June 28, 2006.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.