Airworthiness directives: Saab,
[Federal Register: July 16, 1998 (Volume 63, Number 136)]
[Proposed Rules]
[Page 38353-38355]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr16jy98-31]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-176-AD]
RIN 2120-AA64
Airworthiness Directives; Saab Model SAAB 340B Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Saab Model SAAB 340B series airplanes. This proposal would require a one-time inspection for moisture or other contamination of a certain wiring harness, electrical relay, and relay socket; a one-time inspection for electrical damage of the same electrical relay and socket; corrective actions, if necessary; and replacement of certain nut plates with new, improved parts. This proposal is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed AD are intended to prevent a short circuit caused by fluid leakage, which could result in inability to extend or retract the landing gear.
DATES: Comments must be received by August 17, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-176-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays.
The service information referenced in the proposed rule may be obtained from Saab Aircraft AB, SAAB Aircraft Product Support, S- 581.88, Linkping, Sweden. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.
FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2110; fax (425) 227-1149.
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SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the proposed 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 above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with the substance of this proposal will be filedin the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 98-NM-176-AD.'' The postcard will be date stamped and returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-176-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.
Discussion
The Luftfartsverket (LFV), which is the airworthiness authority for Sweden, notified the FAA that an unsafe condition may exist on certain Saab Model SAAB 340B series airplanes. The LFV advises that it has received a report indicating that circuit breaker 7GA opened while an airplane was in flight, which resulted in the flightcrew being unable to extend and lock down the landing gear. In another incident, circuit breaker 7GA opened shortly after takeoff of an airplane, which resulted in the flightcrew being unable to retract the landing gear. Investigation revealed that the design of nut plates installed on the cockpit floor allowed fluid to leak through carpet attachment holes on the floor. Such fluid leakage contaminated electrical relay 15GA, which is located directly below the nut plates, and caused a short circuit that caused circuit breaker 7GA to open. Fluid leakage also contaminated related wiring harnesses, which could cause the wiring insulation to break down and lead to a short circuit. This condition, if not corrected, could result in inability to extend or retract the landing gear, or possible collapse of the landing gear if it is not locked down properly upon landing.
Explanation of Relevant Service Information
The manufacturer has issued Saab Service Bulletin 340-32-115, dated April 7, 1998. This service bulletin describes procedures for a one- time detailed visual inspection for moisture or other contamination of a wiring harness above relay consoles 305VU and 306VU, and cleaning the wiring harness, if necessary. This service bulletin also describes procedures for a one-time detailed visual inspection for moisture or other contamination of electrical relay 15GA and its socket, which involves removing the relay from its socket; and corrective actions, if necessary. These corrective actions include removing the socket from the relay console, disconnecting the wires from the relay socket, and cleaning the relay socket and relay. This service bulletin also describes procedures for a one-time detailed visual inspection for electrical damage (i.e., arcing, discoloration, or charring) of electrical relay 15GA and its socket; and replacement of the relay and its socket with new parts, if necessary. The service bulletin also describes procedures for replacement of certain existing nut plates on the floor of the cockpit with new, improved parts. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition. The LFV classified this service bulletin as mandatory and issued Swedish airworthiness directive SAD 1-125, dated April 7, 1998, in order to assure the continued airworthiness of these airplanes in Sweden.
FAA's Conclusions
This airplane model is manufactured in Sweden and is 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 LFV has kept the FAA informed of the situation described above. The FAA has examined the findings of the LFV, 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 Proposed 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, the proposed AD would require accomplishment of the actions specified in the service bulletin described previously.
Cost Impact
The FAA estimates that 120 airplanes of U.S. registry would be affected by this proposed AD.
It would take approximately 1 work hour per airplane to accomplish the proposed inspections, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspections proposed by this AD on U.S. operators is estimated to be $7,200, or $60 per airplane.
It would take approximately 3 work hours per airplane to accomplish the proposed replacement, at an average labor rate of $60 per work hour. Required parts would be provided by the manufacturer at no cost to operators. Based on these figures, the cost impact of the replacement proposed by this AD on U.S. operators is estimated to be $21,600, or $180 per airplane.
The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.
Regulatory Impact
The regulations proposed herein would not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this 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) if promulgated, 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. A copy of the draft
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regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
-
The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
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Section 39.13 is amended by adding the following new airworthiness directive:
SAAB Aircraft AB: Docket 98-NM-176-AD.
Applicability: Model SAAB 340B series airplanes, manufacturer serial numbers 380 through 499 inclusive; certificated in any category.
Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
Compliance: Required as indicated, unless accomplished previously.
To prevent a short circuit caused by fluid leakage, which could result in inability to extend or retract the landing gear, accomplish the following:
(a) Within 400 flight hours after the effective date of this AD, accomplish the actions required by paragraphs (a)(1), (a)(2), (a)(3), and (a)(4) of this AD, in accordance with Saab Service Bulletin 340-32-115, dated April 7, 1998.
(1) Perform a detailed visual inspection to detect moisture or other contamination of the electrical wiring harness above relay consoles 305VU and 306VU. If any moisture or other contamination is found, prior to further flight, clean the wiring harness.
(2) Perform a detailed visual inspection to detect moisture or other contamination of electrical relay 15GA and its socket. If any moisture or other contamination is found, prior to further flight, accomplish corrective actions.
(3) Perform a detailed visual inspection for electrical damage of electrical relay 15GA and its socket. If any sign of electrical damage (arcing, discoloration, or charring) is detected, prior to further flight, replace the existing relay and socket with new parts.
(4) Replace the existing nut plates on the floor of the cockpit with new, improved nut plates, on the left and right sides of the airplane.
(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.
Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.
(c) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.
Note 3: The subject of this AD is addressed in Swedish airworthiness directive SAD 1-125, dated April 7, 1998.
Issued in Renton, Washington, on July 8, 1998. S.R. Miller, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 98-18949Filed7-15-98; 8:45 am]
BILLING CODE 4910-13-U
