[Federal Register: March 23, 1998 (Volume 63, Number 55)]
[Proposed Rules]               
[Page 13801-13803]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr23mr98-18]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-43-AD]
RIN 2120-AA64

 
Airworthiness Directives; Construcciones Aeronauticas, S.A. 
(CASA) Model CN-235 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 CASA Model CN-235 series 
airplanes. This proposal would require modification of certain fastener 
holes of the center wing. 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 fatigue cracking in this area, which could result 
in reduced structural integrity of the wing.

DATES: Comments must be received by April 22, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-43-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

[[Page 13802]]

Construcciones Aeronauticas, S.A., Getafe, Madrid, Spain. 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-43-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-43-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Direccion General de Aviacion Civil (DGAC), which is the 
airworthiness authority for Spain, notified the FAA that an unsafe 
condition may exist on certain CASA Model CN-235 series airplanes. The 
DGAC advises that cracks have been found around several fastener holes 
in the structural joints of the center wing structure of the CASA Model 
CN-235 fatigue test article. Fatigue cracking in this area, if not 
detected and corrected in a timely manner, could result in reduced 
structural integrity of the wing.

Explanation of Relevant Service Information

    CASA has issued Service Bulletins SB-235-57-14, Revision 1, dated 
June 21, 1996, and SB-235-57-05, Revision 2, dated June 21, 1996, which 
both describe procedures for modification of the fastener holes of the 
center wing. The modification entails a rototest inspection to detect 
cracking of certain fastener holes of the center wing; removal of 
cracking; and cold working the fastener holes of the center wing to 
increase the expected fatigue life to the design objective for the 
airplane. Accomplishment of the actions specified in the service 
bulletins is intended to adequately address the identified unsafe 
condition.
    The DGAC classified these service bulletins as mandatory and issued 
Spanish airworthiness directive 04/94, dated August 1994, in order to 
assure the continued airworthiness of these airplanes in Spain.

FAA's Conclusions

    This airplane model is manufactured in Spain and is type 
certificated for operation in the United States under the provisions of 
Sec. 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the 
applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, the DGAC has kept the FAA informed 
of the situation described above. The FAA has examined the findings of 
the DGAC, 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 
the actions specified in the service bulletins described previously, 
except as discussed below.

Differences Between Proposed Rule and Foreign AD

    Operators should note that, although the parallel Spanish 
airworthiness directive does not mandate the accomplishment of required 
actions for CASA Model CN-235 series airplane, serial number C-011, the 
applicability of this proposed AD would include that airplane. Although 
that airplane was not certificated for civilian operation by the DGAC, 
the FAA has certificated it as such. The FAA has determined that the 
unsafe condition addressed in this AD may also exist or develop on that 
airplane.

Differences Between Proposed Rule and Related Service Bulletins

    Operators should note that, although the service bulletins specify 
that the manufacturer may be contacted for disposition of certain 
repairs, this proposal would require that any repair, other than those 
specifically identified in the service bulletins, be accomplished in 
accordance with a method approved by the FAA.

Cost Impact

    The FAA estimates that 2 airplanes of U.S. registry would be 
affected by this proposed AD.
    The FAA estimates that the actions specified in CASA Service 
Bulletin SB-235-57-14 would be required to be accomplished on one 
airplane of U.S. registry. These proposed actions would take 
approximately 220 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts would cost 
approximately $719 per airplane. Based on these figures, the cost 
impact of this proposed inspection on the single U.S. operator is 
estimated to be $13,919.
    For CASA Model CN-235 series airplane, serial number C-011, on 
which the actions specified in CASA Service Bulletin SB-235-57-05 would 
be required to be accomplished, those proposed actions would take 
approximately 1,900 work hours per airplane to accomplish, at an 
average labor rate of $60 per work hour. Required parts would cost 
approximately $11,330 per airplane. Based on these figures, the cost 
impact of the proposed actions for that airplane is estimated to be 
$125,330.
    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

[[Page 13803]]

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:
Construcciones Aeronauticas, S.A. (CASA): Docket 97-NM-43-AD.

    Applicability: Model CN-235 series airplanes; as listed in CASA 
Service Bulletins SB-235-57-14, Revision 1, dated June 21, 1996; and 
SB-235-57-05, Revision 2, dated June 21, 1996; and Model CN-235 
having serial number C-011; 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 (d) 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 fatigue cracking in the fastener holes of the center 
wing, which could result in reduced structural integrity of the 
wing, accomplish the following:
    (a) For airplanes listed in CASA Service Bulletins SB-235-57-14, 
Revision 1, dated June 21, 1996; and SB-235-57-05, Revision 2, dated 
June 21, 1996: Perform a rototest inspection of the fastener holes 
of the center wing to detect cracking, in accordance with the 
applicable service bulletin, at the time specified in paragraph (c) 
of this AD.
    (1) If no crack is found, prior to further flight, cold work the 
fastener holes in accordance with the applicable service bulletin.
    (2) If any crack is found, prior to further flight, remove it in 
accordance with the service bulletin; repeat the rototest inspection 
to detect cracking; and cold work the fastener holes, in accordance 
with the applicable service bulletin. If any crack is found that 
cannot be removed using the procedures specified in the applicable 
service bulletin, prior to further flight, repair it in accordance 
with a method approved by the Manager, nternational Branch, ANM-116, 
FAA, Transport Airplane Directorate.
    (b) For airplane serial number C-011: Perform a rototest 
inspection of the fastener holes of the center wing to detect 
cracking, in accordance with CASA Service Bulletin SB-235-57-05, 
Revision 2, dated June 21, 1996, at the time specified in paragraph 
(c) of this AD.
    (1) If no crack is found, prior to further flight, cold work the 
fastener holes in accordance with the service bulletin.
    (2) If any crack is found, prior to further flight, remove it in 
accordance with the service bulletin; repeat the rototest inspection 
to detect cracking; and cold work the fastener holes, in accordance 
with the service bulletin. If any crack is found that cannot be 
removed using the procedures specified in the service bulletin, 
prior to further flight, repair it in accordance with a method 
approved by the Manager, International Branch, ANM-116, FAA, 
Transport Airplane Directorate.
    (c) Accomplish the inspection required by paragraph (a) or (b) 
of this AD, as applicable, at the later of the times specified in 
paragraphs (c)(1) and (c)(2) of this AD.
    (1) Prior to the accumulation of 17,000 total flight cycles or 
37,400 total flight hours, whichever occurs first.
    (2) Within 6 months after the effective date of this AD.
    (d) 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 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.

    (e) Special flight permits may be issued in accordance with 
Secs. 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 Spanish 
airworthiness directive 04/94, dated August 1994.

    2Issued in Renton, Washington, on March 16, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-7366 Filed 3-20-98; 8:45 am]
BILLING CODE 4910-13-P