[Federal Register Volume 63, Number 110 (Tuesday, June 9, 1998)]
[Proposed Rules]
[Pages 31380-31382]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-15248]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-151-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 a one-time inspection for 
cracking of the rear pressure bulkhead; and installation of a 
reinforcement angle on the rear pressure bulkhead; or repair, if 
necessary. 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 cracking of the rear pressure bulkhead, which could result in 
sudden loss of cabin pressure and the inability to withstand fail-safe 
loads.

DATES: Comments must be received by July 9, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-151-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.

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 98-NM-151-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. 98-NM-151-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, during 
full-scale fatigue testing on a test article, a crack was detected on 
the radius of the lower forward flange that connects the rear pressure 
bulkhead to the fuselage skin. The crack occurred when the test article 
reached 68,000 simulated flights. The LFV further advises that 
reinforcement of the lower forward flange area that connects the rear 
pressure bulkhead to the fuselage skin is required to meet the design 
life of the airplane. Such cracking, if not corrected, could result in 
sudden loss of cabin pressure and the inability to withstand fail-safe 
loads.

Explanation of Relevant Service Information

    The manufacturer has issued SAAB Service Bulletin 2000-53-026, 
dated February 27, 1998, which describes procedures for a one-time 
inspection to detect cracking of the rear pressure bulkhead in the area 
of the lower forward flange that connects to the fuselage skin. 
Additionally, for airplanes on which no cracking is found, the service 
bulletin describes procedures for installation of a reinforcement angle 
on the rear pressure bulkhead in the area of the lower forward flange 
that connects to the fuselage skin. 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 1-122, dated 
March 2, 1998, in order to assure the

[[Page 31381]]

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 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, except 
as discussed below.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that although the service bulletin specifies 
that the manufacturer may be contacted for disposition of cracks, this 
proposal would require the repair of those cracks be accomplished in 
accordance with a method approved by either the Manager, International 
Branch, ANM-116, FAA Transport Directorate; or the LFV (or its 
delegated agent). In light of the type of repair that would be required 
to address the identified unsafe condition, and in consonance with 
existing bilateral airworthiness agreements, the FAA has determined 
that, for this proposed AD, a repair approved by either the FAA or the 
LFV (or its delegated agent) would be acceptable for compliance with 
this proposed AD.

Cost Impact

    The FAA estimates that 3 airplanes of U.S. registry would be 
affected by this proposed AD.
    It would take approximately 6 work hours per airplane to accomplish 
the proposed inspection, at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of the inspection proposed by 
this AD on U.S. operators is estimated to be $1,080, or $360 per 
airplane.
    The proposed installation would take approximately 10 work hours 
per airplane, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact of the installation proposed by this AD 
on U.S. operators is estimated to be $1,800, or $600 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 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 98-NM-151-AD.

    Applicability: Model SAAB 2000 series airplanes, manufacturer 
serial numbers 004 through 050 inclusive, 052, 053, and 054; 
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 cracking on the rear pressure bulkhead, which could 
result in sudden loss of cabin pressure and the inability to 
withstand fail-safe loads, accomplish the following:
    (a) Within 4,000 flight cycles after the effective date of this 
AD, perform a one-time visual inspection for cracking on the rear 
pressure bulkhead in the area of the lower forward flange that 
connects to the fuselage skin, in accordance with SAAB Service 
Bulletin 2000-53-026, dated February 27, 1998.
    (1) If no crack is detected, prior to further flight, install a 
reinforcement angle on the rear pressure bulkhead in the area of the 
lower forward flange that connects to the fuselage skin, in 
accordance with the service bulletin. After accomplishment of the 
installation, no further action is required by this AD.
    (2) If any crack is detected, prior to further flight, repair in 
accordance with a method approved by either the Manager, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
or the Luftfartsverket (or its delegated agent).
    (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. 
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 1-122, dated March 2, 1998.


[[Page 31382]]


    Issued in Renton, Washington, on June 3, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-15248 Filed 6-8-98; 8:45 am]
BILLING CODE 4910-13-U