[Federal Register Volume 63, Number 134 (Tuesday, July 14, 1998)]
[Proposed Rules]
[Pages 37795-37796]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-18645]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-144-AD]
RIN 2120-AA64


Airworthiness Directives; Saab Model 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 2000 
series airplanes. This proposal would require replacing the radio 
tuning units (RTU's) and associated components 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 NAV/
COM radios from simultaneously changing tuned frequencies and 
transponder codes due to a black screen failure or ``blanking'' of an 
RTU, which could result in loss of communications capability and air 
traffic control data.

DATES: Comments must be received by August 13, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-144-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.

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 97-NM-144-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. 97-NM-144-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 2000 series airplanes. The LFV advises that, in the 
event of a ``blanking'' (black screen) failure of a single radio tuning 
unit (RTU), the NAV/COM radios may change tuned radio frequencies and 
transponder codes. Such frequency and transponder code changes may 
occur on both left and right NAV/COM radios simultaneously. This 
condition, if not corrected, could result in loss of communications 
capability and air traffic control data.
    The manufacturer of the RTU's reported that this ``blanking'' 
failure of an RTU is a design problem that was discovered during an 
investigation of a service difficulty on another airplane model. The 
RTU's installed on certain Saab Model SAAB 2000 series airplanes are 
the same type as those on the other airplane model. Therefore, Saab 
Model SAAB 2000 series airplanes may be subject to the same unsafe 
condition.

Explanation of Relevant Service Information

    The manufacturer has issued Saab Service Bulletin 2000-23-017, 
dated March 10, 1997, which describes procedures for replacing existing 
RTU's and associated components with new, improved parts. The improved 
RTU's are not susceptible to frequency or transponder code changes due 
to a ``blanking'' failure. 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 1-109, dated March 12, 
1997, 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

[[Page 37796]]

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 
actions specified in the service bulletin described previously.

Cost Impact

    The FAA estimates that 3 airplanes of U.S. registry would be 
affected by this proposed AD, and that it would take approximately 2 
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 of the RTU 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 $360, or $120 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.

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 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 97-NM-144-AD.

    Applicability: Model SAAB 2000 series airplanes, as listed in 
Saab Service Bulletin 2000-23-017, dated March 10, 1997; 
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 NAV/COM radios from simultaneously changing tuned 
frequencies and transponder codes due to a black screen failure or 
``blanking'' of a radio tuning unit (RTU), which could result in 
loss of communications capability and air traffic control data, 
accomplish the following:
    (a) Within 1 year after the effective date of this AD, replace 
the existing RTU's and associated components with new, improved 
parts, in accordance with Saab Service Bulletin 2000-23-017, dated 
March 10, 1997.
    (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 request 
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 1-109, dated March 12, 1997.

    Issued in Renton, Washington, on July 7, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-18645 Filed 7-13-98; 8:45 am]
BILLING CODE 4910-13-P