[Federal Register Volume 61, Number 56 (Thursday, March 21, 1996)]
[Proposed Rules]
[Pages 11591-11593]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-6809]



      
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 Proposed Rules
                                                 Federal Register
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
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 

  Federal Register / Vol. 61, No. 56 / Thursday, March 21, 1996 / 
Proposed Rules  

[[Page 11591]]


DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-243-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 installation of 
an automatic flight idle stop on the control quadrant in the flight 
compartment. This proposal is prompted by several reports of one or 
both power levers being moved aft of the flight idle stop on approach. 
The actions specified by the proposed AD are intended to prevent such 
movement of the power lever(s) during flight, which could result in the 
loss of power to one or both engines, as well as severe engine damage.

DATES: Comments must be received by April 19, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-243-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: Ruth E. 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 must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 95-NM-243-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-243-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 received a report indicating that the flight crew on a 
Model SAAB 340B series airplane moved both power levers aft of the 
flight idle stop when the airplane was on approach. This movement of 
the power levers resulted in loss of power to both engines. Both 
engines sustained extensive mechanical damage due to propeller 
overspeed, which resulted in a forced landing. Additionally, there have 
been several other incidents where the flight crew on a Model SAAB 340B 
series airplane moved one or both power levers aft of the flight idle 
stop during flight. -
    When the power levers are moved aft of the flight idle stop into 
the beta range during flight, it is possible for air loads to back-
drive the propeller, which could result in overspeed of the propeller 
and power turbine of the engine. (``Beta'' is the range of propeller 
operation intended for use during taxi, ground idle, or reverse 
operations, as controlled by the power lever settings aft of the flight 
idle stop.) Within the beta range, the propeller blade angle is 
proportional to the power lever position, and the propeller power 
control unit (PCU) is not controlling blade pitch or providing 
propeller overspeed protection. -
    Saab has issued Service Bulletin 340-76-032, Revision 01, dated 
September 25, 1995, which describes procedures for installation of an 
automatic flight idle stop on the control quadrant in the flight 
compartment. The installation involves removing the mechanical beta 
stop (if installed), removing the old control quadrant, installing a 
new/modified control quadrant, and accomplishing a functional test of 
the flight idle stop system. Accomplishment of this installation will 
prevent the power levers from being moved aft of the flight idle 
position during flight.-
    The service bulletin specifies that certain additional actions are 
necessary as part of installing an automatic flight idle stop. These 
additional actions may be accomplished prior to, or in conjunction 
with, the accomplishment of Saab Service Bulletin 340-76-032. The 
actions are described in the following Saab service bulletins: -
     Service Bulletin 340-76-031, Revision 02, dated September 
25, 1995, which describes procedures for modification of the electrical 
system of the flight idle stop. The modification entails installing new 
relays and a

[[Page 11592]]
console in certain electrical centers, installing indicator lamps in 
the center instrument panel, and routing of all necessary wiring for 
these functions. -
     Service Bulletin 340-32-100, Revision 01, dated September 
25, 1995, which describes procedures for installing a control unit with 
a wheel spin-up signal. The installation involves removing the 
currently installed anti-skid control unit and installing new/modified 
anti-skid control unit having a new part number. -
    The LFV classified these service bulletins as mandatory and issued 
Swedish airworthiness directive 1-070, dated April 10, 1995, in order 
to assure the continued airworthiness of these airplanes in Sweden. -
    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, the 
proposed AD would require installation of an automatic flight idle stop 
on the control quadrant in the flight compartment. The actions would be 
required to be accomplished in accordance with the service bulletins 
described previously. -
    Operators should note that, although the Swedish AD requires 
accomplishing the installation within 20 months (after the effective 
date of the Swedish AD), this proposed AD would require accomplishing 
the installation within 12 months. In developing an appropriate 
compliance time for this proposed AD, the FAA considered not only the 
LFV's recommendation, but the degree of urgency associated with 
addressing the subject unsafe condition, parts availability, and the 
time necessary to perform the installation. In light of all of these 
factors, the FAA finds 12 months to be an appropriate compliance time 
for initiating the proposed action in that it represents the maximum 
interval of time allowable for affected airplanes to continue to 
operate without compromising safety. -
    The FAA estimates that 224 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take between 122 and 142 
work hours per airplane to accomplish the proposed actions, depending 
upon the configuration of the airplane. The average labor rate is $60 
per work hour. Required parts would cost approximately $9,300 per 
airplane. Based on these figures, the cost impact of the proposed AD on 
U.S. operators is estimated to be between $3,722,880 and $3,991,680 
(between $16,620 and $17,820 per airplane). -
    The cost impact figure discussed above 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 FAA recognizes that the obligation to maintain aircraft in an 
airworthy condition is vital, but sometimes expensive. Because AD's 
require specific actions to address specific unsafe conditions, they 
appear to impose costs that would not otherwise be borne by operators. 
However, because of the general obligation of operators to maintain 
aircraft in an airworthy condition, this appearance is deceptive. 
Attributing those costs solely to the issuance of this AD is 
unrealistic because, in the interest of maintaining safe aircraft, 
prudent operators would accomplish the required actions even if they 
were not required to do so by the AD. -
    A full cost-benefit analysis has not been accomplished for this 
proposed AD. As a matter of law, in order to be airworthy, an aircraft 
must conform to its type design and be in a condition for safe 
operation. The type design is approved only after the FAA makes a 
determination that it complies with all applicable airworthiness 
requirements. In adopting and maintaining those requirements, the FAA 
has already made the determination that they establish a level of 
safety that is cost-beneficial. When the FAA, as in this proposed AD, 
makes a finding of an unsafe condition, this means that the original 
cost-beneficial level of safety is no longer being achieved and that 
the proposed actions are necessary to restore that level of safety. 
Because this level of safety has already been determined to be cost-
beneficial, a full cost-benefit analysis for this proposed AD would be 
redundant and unnecessary. -
    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), 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-243-AD.

     -Applicability: Model SAAB SF340A series airplanes, serial 
numbers -004 through -159 inclusive; and Model SAAB 340B series 
airplanes, serial numbers -160 through -379 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.

 -
[[Page 11593]]

    Compliance: Required as indicated, unless accomplished 
previously. -
    To prevent the movement of both power levers aft of the flight 
idle stop during flight, which could result in loss of power to both 
engines, as well as severe engine damage, accomplish the following: 
-
    (a) Within 12 months after the effective date of this AD, 
accomplish the requirements of paragraphs (a)(1), (a)(2), and (a)(3) 
of this AD. -
    (1) Modify the electrical system of the flight idle stop in 
accordance with Saab Service Bulletin 340-76-031, Revision 02, dated 
September 25, 1995; and -
    (2) Install a control unit with a wheel spin-up signal in 
accordance with Saab Service Bulletin 340-32-100, Revision 01, dated 
September 25, 1995; and -
    (3) Install an automatic flight idle stop on the control 
quadrant in the flight compartment in accordance with Saab Service 
Bulletin 340-76-032, Revision 01, dated September 25, 1995.

    -Note 2: The actions specified in paragraphs (a)(1) and (a)(2) 
of this AD may be accomplished prior to, or in conjunction with, the 
accomplishment of the requirement of paragraph (a)(3) of this AD.

     -Note 3: Paragraph 2.A. of the Accomplishment Instructions of 
Saab Service Bulletin 340-76-032, Revision 01, dated September 25, 
1995, specifies procedures for removal of a mechanical beta stop 
mechanism from the airplane. Since installation of a mechanical beta 
stop mechanism was not required previously by AD, that mechanism may 
not have been installed on certain airplanes affected by this AD. In 
such cases, procedures for removal of the mechanical beta stop would 
not apply.

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

     -(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. Issued in Renton, 
Washington, on March 15, 1996.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-6809 Filed 3-20-96; 8:45 am]
BILLING CODE 4910-13-P