[Federal Register Volume 61, Number 172 (Wednesday, September 4, 1996)]
[Proposed Rules]
[Pages 46572-46574]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-22475]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-69-AD]
RIN 2120-AA64


Airworthiness Directives; Saab Model SAAB SF340A, SAAB 340B, and 
SAAB 2000 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, 
SAAB 340B, and SAAB 2000 series airplanes. This proposal would require 
replacement of the hubcap drive coupling of the main wheel with an 
improved coupling. This proposal is prompted by reports of unexpected 
decreases in the pressure of the main wheel brake due to incorrect 
engagement between the main wheel coupling and the wheel speed 
transducer, which can result in false signals being sent to the anti-
skid control box. The actions specified by the proposed AD are intended 
to prevent loss of brake effectiveness due to a decrease in the 
pressure of the main wheel brake.

DATES: Comments must be received by October 15, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-69-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, or at the FAA, Transport Airplane Directorate, Los Angeles 
Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, 
California.

FOR FURTHER INFORMATION CONTACT: Walter Eierman, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130L, FAA, Los Angeles Aircraft 
Certification Office, 3960 Paramount

[[Page 46573]]

Boulevard, Lakewood, California 90712; telephone (310) 627-5336; fax 
(310) 627-5210.

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 96-NM-69-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. 96-NM-69-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, SAAB 340B and SAAB 2000 series 
airplanes. The LFV advises that it has received reports indicating that 
sudden and unexpected decreases in the pressure of the main wheel brake 
occurred due to incorrect engagement between the drive coupling of the 
main wheel and the wheel speed transducer. Investigation revealed that 
constant removal and reinstallation of the main wheel hubcap during 
maintenance eventually can cause large gaps or cracks in the drive 
coupling. Such damage can prevent the drive coupling and wheel speed 
transducer from engaging properly, and ultimately, can result in a 
false signal being sent to the anti-skid control box; this can cause 
main wheel brake pressure to decrease. This condition, if not 
corrected, could result in a loss of brake effectiveness.

Explanation of Relevant Service Information

    Saab has issued Service Bulletins SAAB 340-32-107 (for Model SAAB 
SF340A and SAAB 340B series airplanes), and SAAB 2000-32-019 (for Model 
SAAB 2000 series airplanes), both dated January 18, 1996. These service 
bulletins describe procedures for replacing the hubcap drive coupling 
of the main wheel with an improved coupling that is more resistant to 
damage from the removal and reinstallation of the main wheel hubcap. 
The Saab service bulletins reference Crane Hydro-Aire Division Service 
Bulletins 140-041-32-1 (for wheel hubcaps having part number 140-04120) 
and 140-159-32-1 (for wheel hubcaps having part number 140-15920), both 
dated December 21, 1995, as additional sources of service information 
for replacement of the hubcap drive coupling.
    The LFV classified these Saab service bulletins as mandatory and 
issued Swedish Airworthiness Directive (SAD) 1-085R1, dated January 22, 
1996, in order to assure the continued airworthiness of these airplanes 
in Sweden.

FAA's Conclusions

    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.

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 replacement of the 
hubcap drive coupling of the main wheel with an improved coupling. The 
actions would be required to be accomplished in accordance with the 
service bulletins described previously.

Cost Impact

    The FAA estimates that 235 Model SAAB SF340A and SAAB 340B series 
airplanes and 3 Model SAAB 2000 series airplanes of U.S. registry would 
be affected by this proposed AD.
    For Model SAAB SF340A and SAAB 340B series airplanes, it would take 
approximately 2 work hours per airplane to accomplish the proposed 
actions, at an average labor rate of $60 per work hour. Required parts 
would cost approximately $200 per airplane. Based on these figures, the 
cost impact of the proposed AD on U.S. operators of Model SAAB 340A and 
SAAB 340B series airplanes is estimated to be $75,200, or $320 per 
airplane.
    For Model SAAB 2000 series airplanes, it would take approximately 2 
work hours per airplane to accomplish the proposed actions, at an 
average labor rate of $60 per work hour. Required parts would cost 
approximately $120 per airplane. Based on these figures, the cost 
impact of the proposed AD on U.S. operators of Model SAAB 2000 series 
airplanes is estimated to be $720, or $240 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 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by

[[Page 46574]]

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 96-NM-69-AD.

    Applicability: Model SAAB SF340A series airplanes having serial 
numbers 004 through 159 inclusive; Model SAAB 340B series airplanes 
having serial numbers 160 through 378 inclusive; and Model SAAB 2000 
series airplanes having serial numbers 002 through 029 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 
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 request approval for an 
alternative method of compliance in accordance with paragraph (c) 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 loss of brake effectiveness due to a decrease in 
pressure of the main wheel brake, accomplish the following:
    (a) Within 90 days after the effective date of this AD, replace 
each main wheel hubcap drive coupling having part number (P/N) 40-
91115 with a main wheel hubcap drive coupling having P/N 40-91115, 
Rev. D, in accordance with Saab Service Bulletin SAAB 340-32-107, 
dated January 18, 1996 (for Model SAAB SF340A and SAAB 340B series 
airplanes), or Saab Service Bulletin SAAB 2000-32-019, dated January 
18, 1996 (for Model SAAB 2000 series airplanes), as applicable.

    Note 2: The Saab service bulletins reference Crane Hydro-Aire 
Division Service Bulletins 140-041-32-1 (for wheel hubcaps having 
part number 140-04120) and 140-159-32-1 (for wheel hubcaps having 
part number 140-15920), both dated December 21, 1995, as additional 
sources of service information for replacement of the hubcap drive 
coupling.

    (b) As of the effective date of this AD, no person shall install 
on any airplane a main wheel hubcap drive coupling having P/N 40-
91115 in a wheel hubcap having P/N 140-04120 (for Model SAAB SF340A 
and SAAB 340B series airplanes), or P/N 140-15920 (for Model SAAB 
2000 series airplanes), as applicable.
    (c) 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, Los Angeles Aircraft Certification 
Office (ACO), 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, Los Angeles ACO.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (d) 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 August 28, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-22475 Filed 9-3-96; 8:45 am]
BILLING CODE 4910-13-U