[Federal Register Volume 62, Number 33 (Wednesday, February 19, 1997)]
[Proposed Rules]
[Pages 7382-7384]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-3968]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-138-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 replacement of the guide hooks 
of the cargo doors with new, improved guide hooks. This proposal is 
prompted by fatigue cracking found in the guide hooks of the cargo 
door. The actions specified by the proposed AD are intended to prevent 
such fatigue cracking, which could result in reduced structural 
integrity of the cargo door and, consequently, lead to rapid 
decompression of the airplane.

DATES: Comments must be received by March 31, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-138-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 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: Greg Dunn, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2799; fax (206) 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

[[Page 7383]]

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-138-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-138-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Direction Generale de l'Aviation Civile (DGAC), which is the 
airworthiness authority for Spain, recently notified the FAA that an 
unsafe condition may exist on certain CASA CN-235 series airplanes. The 
DGAC advises that, during full-scale fatigue tests on a Model CN-235 
test article, cracking was found in the guide hooks of the cargo door. 
Such cracking is attributed to fatigue-related stress. Fatigue-related 
cracking in the guide hooks of the cargo door, if not detected and 
corrected in a timely manner, could result in reduced structural 
integrity of the cargo door and, consequently, lead to rapid 
decompression of the airplane.

Explanation of Relevant Service Information

    CASA has issued Service Bulletin SB-235-52-23, Revision 2, dated 
June 9, 1994, and Service Bulletin SB-235-52-23M, dated March 17, 1994. 
These service bulletins describe procedures for replacement of the 
guide hooks of the cargo doors with new, improved guide hooks. The 
replacement improves the fatigue life of the cargo doors. The DGAC 
classified these service bulletins as mandatory and issued Spanish 
airworthiness directive 02/94, 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 
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 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 replacement of the 
guide hooks of the cargo doors with new, improved guide hooks. The 
actions would be required to be accomplished in accordance with the 
applicable service bulletin described previously.

Cost Impact

    The FAA estimates that 1 airplane of U.S. registry would be 
affected by this proposed AD, that it would take approximately 150 work 
hours per airplane to accomplish the proposed actions, and that the 
average labor rate is $60 per work hour. Required parts would cost 
approximately $6,100 per airplane. Based on these figures, the cost 
impact of the proposed AD on U.S. operators is estimated to be $15,100 
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:

Construcciones Aeronauticas, S.A., CASA: Docket 96-NM-138-AD.

    Applicability: Model CN-235 series airplanes, as listed in CASA 
Service Bulletin SB-235-52-23, Revision 2, dated June 9, 1994, and 
CASA Service Bulletin SB-235-52-23M, dated March 17, 1994; 
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 (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.

[[Page 7384]]

    To prevent fatigue-related cracking in the guide hooks of the 
cargo door, which could result in reduced structural integrity of 
the cargo door and, consequently, lead to rapid decompression of the 
airplane, accomplish the following:
    (a) Replace the guide hooks of the cargo doors with new, 
improved guide hooks, in accordance with CASA Service Bulletin SB-
235-52-23, Revision 2, dated June 9, 1994, or CASA Service Bulletin 
SB-235-52-23M, dated March 17, 1994; at the time specified in 
paragraph (a)(1) or (a)(2) of this AD, as applicable.

    Note 2: Replacements accomplished prior to the effective date of 
this AD in accordance with CASA Service Bulletin SB-235-52-23, dated 
June 16, 1993, or Revision 1, dated April 13, 1994, are considered 
acceptable for compliance with the requirements of paragraph (a) of 
this AD.
    (1) For airplanes listed in CASA Service Bulletin SB-235-52-23: 
Replace prior to the accumulation of 17,000 total landings.
    (2) For airplanes listed in CASA Service Bulletin SB-235-52-23M: 
Replace prior to the accumulation of 15,000 total landings.
    (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, Standardization Branch, ANM-113, 
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, 
Standardization Branch, ANM-113.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.
    (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.

    Issued in Renton, Washington, on February 11, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-3968 Filed 2-18-97; 8:45 am]
BILLING CODE 4910-13-U