[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
________________________________________________________________________
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
