[Federal Register Volume 60, Number 216 (Wednesday, November 8, 1995)]
[Proposed Rules]
[Pages 56274-56276]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-27646]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-79-AD]


Airworthiness Directives; Saab Model SAAB SF340A and 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 SF340A and 
SAAB 340B series airplanes. This proposal would require repetitive 
operational tests of the valve limit switch of the propeller brake. 
This proposal also provides for an optional terminating action for the 
repetitive tests. This proposal is prompted by a report that when the 
propeller brake was not properly engaged the crew did not receive a 
``PROP BRAKE'' warning due to a faulty valve limit switch. The actions 
specified by the proposed AD are intended to prevent a valve limit 
switch from failing to send input to the warning system; absence of a 
``PROP BRAKE'' warning could result in the crew being unaware that the 
propeller brake is not properly engaged and the propeller may turn 
without warning.

DATES: Comments must be received by December 19, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-79-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, Linkoping, Sweden. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Ruth Harder, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-1721; fax (206) 227-1149.

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 

[[Page 56275]]
must submit a self-addressed, stamped postcard on which the following 
statement is made: ``Comments to Docket Number 95-NM-79-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-103, Attention: Rules 
Docket No. 95-NM-79-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Luftfartsverket (LFV), which is the airworthiness authority for 
Sweden, recently notified the FAA that an unsafe condition may exist on 
certain Saab Model SAAB SF340A and SAAB 340B series airplanes. The LFV 
advises that it has received a report indicating that the flightcrew of 
one airplane did not receive a ``PROP BRAKE'' warning when the 
propeller brake was not properly engaged. The ``PROP BRAKE'' warning 
indicates that there is insufficient [below 2,350 pounds per square 
inch (psi)] hydraulic pressure to engage the propeller brake. 
Investigation revealed that this failure was caused by a failure mode 
in the valve limit switch of the propeller brake system. If a valve 
limit switch is faulty, no input would be sent the warning system; this 
situation could result in the flightcrew being unaware that the 
propeller brake is not properly engaged and the propeller may turn 
without warning.
    Saab has issued Service Bulletin SAAB 340-61-032, Revision 1, dated 
June 30, 1995, which describes procedures for repetitive operational 
tests of the valve limit switch of the propeller brake. The LFV 
classified this service bulletin as mandatory and issued Swedish 
airworthiness directive (SAD) 1-064, Revision 1, effective date March 
24, 1995, in order to assure the continued airworthiness of these 
airplanes in Sweden.
    Saab has also issued Service Bulletin SAAB 340-61-033, dated March 
6, 1995, which describes procedures for replacement of the propeller 
brake control unit having part number (P/N) HP1410100-3, -5, or -7 with 
a new propeller brake control unit having P/N HP1410100-10, and an 
operational test. Accomplishment of this replacement eliminates the 
need for the repetitive operational tests. The new propeller brake 
control unit has an improved low pressure valve limit switch installed 
in it to ensure that its inputs are received by the warning system. The 
LFV approved the technical content of this service bulletin.
    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 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.
    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 repetitive 
operational tests of the valve limit switch of the propeller brake. The 
proposed AD also provides for the optional replacement of certain 
propeller brake control units with a new unit, which would constitute 
terminating action for the repetitive test requirements. The actions 
would be required to be accomplished in accordance with the service 
bulletins described previously.
    The FAA estimates that 23 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 operational tests, at an average labor rate of $60 per 
work hour. Based on these figures, the total cost impact of the actions 
that would be required by this AD on U.S. operators is estimated to be 
$1,380, or $60 per airplane, per test cycle. This total cost impact 
figure is 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.
    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 
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), 40101, 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

SAAB Aircraft AB: Docket 95-NM-79-AD.

    Applicability: Model SAAB SF340A series airplanes, having serial 
numbers 004 through 159 inclusive; and Model SAAB 340B series 
airplanes, having serial numbers 160 through 369 inclusive; on which 
the propeller brake system is connected; certificated in any 
category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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 use the authority 
provided in paragraph (d) of this AD to request approval from the 
FAA. This approval may address either no action, if the current 
configuration eliminates the unsafe condition; or different actions 
necessary to address the unsafe condition described in this AD. Such 
a request should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent a valve limit switch from failing to send input to 
the ``PROP BRAKE'' warning system, which could result in the crew 
being 

[[Page 56276]]
unaware that the propeller brake is not properly engaged and the 
propeller may turn without warning, accomplish the following:
    (a) Within 100 flight hours after the effective date of this AD, 
perform an operational test of the valve limit switch of the 
propeller brake in accordance with Saab Service Bulletin SAAB 340-
61-032, Revision 1, dated June 30, 1995. Repeat the test thereafter 
at intervals not to exceed 100 flight hours.
    (b) Replacement of a propeller brake control unit having part 
number (P/N) HP1410100-3, -5, or -7 with a new propeller brake 
control unit having P/N HP1410100-10, and performance of an 
operational test, in accordance with SAAB Service Bulletin SAAB 340-
61-033, dated March 6, 1995. constitutes terminating action for the 
repetitive inspections required by paragraph (a) of this AD.
    (c) As of the effective date of this AD, no person shall install 
on any airplane a propeller brake control unit having P/N HP1410100-
3; or any unit having P/N HP1410100-5 or -7 unless that unit has 
been modified in accordance with SAAB Service Bulletin SAAB 340-61-
033, dated March 6, 1995.
    (d) 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, Standardization Branch, ANM-113, 
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, 
Standardization Branch, ANM-113.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (e) 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.

    Issued in Renton, Washington, on November 2, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-27646 Filed 11-7-95; 8:45 am]
BILLING CODE 4910-13-U