AD Amdt-39-10816

[Federal Register Volume 63, Number 191 (Friday, October 2, 1998)]
[Rules and Regulations]
[Pages 52961-52963]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 98-26389]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-287-AD; Amendment 39-10816; AD 98-21-08]
RIN 2120-AA64


Airworthiness Directives; Saab Model SAAB 2000 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain Saab Model SAAB 2000 series airplanes. This 
action requires repetitive functional tests (checks) to verify proper 
operation of the nose wheel steering system (NWSS) limitswitch, and 
replacement of the existing limitswitch with a new limitswitch, if 
necessary. This amendment is prompted by issuance of mandatory 
continuing airworthiness information by a foreign civil airworthiness 
authority. The actions specified in this AD are intended to prevent 
combined failure of the limitswitch and the feedback shaft in the NWSS 
servo unit, which could result in uncommanded nose wheel steering 
deflection and reduced controllability of the airplane on the ground 
during takeoff or landing.


[[Page 52962]]


DATES: Effective October 19, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of October 19, 1998.
    Comments for inclusion in the Rules Docket must be received on or 
before November 2, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-287-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    The service information referenced in this AD 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 
Office of the Federal Register, 800 North Capitol Street, NW., suite 
700, Washington, DC.

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: 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 it received a report of uncommanded nose wheel 
steering deflection during landing of a Saab Model SAAB 2000 series 
airplane, without pilot engagement of the steering system. This 
deflection was attributed to a short circuit in the nose wheel steering 
system (NWSS) limitswitch, in combination with a failure of the 
feedback shaft in the NWSS servo unit. The LFV also advised the FAA 
that previous failures of the feedback shaft have been reported and 
corrective action for the NWSS servo units is presently being 
evaluated. Such combined failure of the limitswitch and the feedback 
shaft could result in uncommanded nose wheel steering deflection and 
reduced controllability of the airplane on the ground during takeoff or 
landing.

Explanation of Relevant Service Information

    Saab has issued Service Bulletin 2000-32-050, dated August 24, 
1998, which describes procedures for repetitive functional tests 
(checks) to verify proper operation of the NWSS limitswitch, and 
replacement of the limitswitch, if necessary. The LFV classified this 
service bulletin as mandatory and issued Swedish airworthiness 
directive SAD 1-130, dated August 27, 1998, 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 
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 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, this AD is being issued to prevent combined 
failure of the limitswitch and the feedback shaft of the NWSS, which 
could result in reduced controllability of the airplane on the ground 
during takeoff or landing. This AD requires accomplishment of the 
actions specified in the service bulletin described previously.

Interim Action

    The FAA is considering further rulemaking action to supersede this 
AD to require modification of the feedback shaft in the NWSS servo 
units, which will constitute terminating action for the repetitive 
functional tests (checks) required by this AD action. However, the 
planned compliance time for these actions is sufficiently long so that 
prior notice and time for public comment will be practicable.

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 98-NM-287-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory

[[Page 52963]]

Policies and Procedures, a final regulatory evaluation will be prepared 
and placed in the Rules Docket. A copy of it, if filed, may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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:

98-21-08  Saab Aircraft AB: Amendment 39-10816. Docket 98-NM-287-AD.

    Applicability: Model SAAB 2000 series airplanes, serial numbers 
004 through 063 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.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent combined failure of the limitswitch and the feedback 
shaft in the nose wheel steering system (NWSS) servo unit, which 
could result in uncommanded nose wheel steering deflection and 
reduced controllability of the airplane on the ground during takeoff 
or landing, accomplish the following:
    (a) Within 3 weeks after the effective date of this AD, perform 
a functional test (check) to verify proper operation of the NWSS 
limitswitch, in accordance with Saab Service Bulletin 2000-32-050, 
dated August 24, 1998.
    (1) If no malfunction is detected, repeat the functional test 
thereafter at intervals not to exceed 400 flight hours.
    (2) If any malfunction is detected, prior to further flight, 
replace the existing limitswitch with a new limitswitch in 
accordance with the service bulletin. Repeat the functional test 
thereafter at intervals not to exceed 400 flight hours.
    (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 
requests 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.
    (d) The functional tests (checks) and replacement shall be done 
in accordance with Saab Service Bulletin 2000-32-050, dated August 
24, 1998. This incorporation by reference was approved by the 
Director of the Federal Register in accordance with 5 U.S.C. 552(a) 
and 1 CFR part 51. Copies may be obtained from Saab Aircraft AB, 
SAAB Aircraft Product Support, S-581.88, Linko-ping, Sweden. Copies 
may be inspected at the FAA, Transport Airplane Directorate, 1601 
Lind Avenue, SW., Renton, Washington; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

    Note 3: The subject of this AD is addressed in Swedish 
airworthiness directive SAD 1-130, dated August 27, 1998.

    (e) This amendment becomes effective on October 19, 1998.

    Issued in Renton, Washington, on September 28, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-26389 Filed 10-1-98; 8:45 am]
BILLING CODE 4910-13-P