[Federal Register Volume 63, Number 136 (Thursday, July 16, 1998)]
[Proposed Rules]
[Pages 38353-38355]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-18949]
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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).
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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.
[[Page 38354]]
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 filed in 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
[[Page 38355]]
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
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. 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. 98-18949 Filed 7-15-98; 8:45 am]
BILLING CODE 4910-13-U
