[Federal Register Volume 62, Number 41 (Monday, March 3, 1997)]
[Proposed Rules]
[Pages 9388-9390]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-5160]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-126-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).

-----------------------------------------------------------------------

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 a one-time inspection to detect 
fatigue cracking in the area of the center wing-to-fuselage attachment 
fitting, and repair, if necessary. This proposal also would require 
installation of a reinforcing plate in the attachment area of that 
fitting. This proposal is prompted by a report from the manufacturer 
indicating that, during full-scale fatigue testing, fatigue cracks were 
detected in this area. The actions specified by the proposed AD are 
intended to prevent fatigue cracking, which consequently could reduce 
the structural integrity of this area.

DATES: Comments must be received by April 10, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-126-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 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 Number96-NM-126-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-126-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

[[Page 9389]]

Discussion

    The Direccion General de Aviacion (DGAC), which is the 
airworthiness authority for Spain, recently notified the FAA that an 
unsafe condition may exist on certain CASA Model CN-235 series 
airplanes. The DGAC advises that it has received a report from the 
manufacturer indicating that, during full-scale fatigue testing, 
fatigue cracks were detected on the test article in the area of the 
center wing-to-fuselage attachment fitting. This condition, if not 
prevented, could reduce the structural integrity of this area.

Explanation of Relevant Service Information

    CASA has issued Service Bulletin SB-235-53-20, Revision 2, dated 
June 9, 1994 (for non-military airplanes), and Service Bulletin SB-235-
53-20M, Revision 1, dated November 27, 1995 (for military airplanes). 
Both service bulletins describe procedures for installing a reinforcing 
plate in the attachment area of the center wing-to-fuselage attachment 
fitting. Installation of the reinforcing plate will preclude the 
development of fatigue cracking in the attachment area.
    The DGAC classified CASA Service Bulletin SB-235-53-20 as mandatory 
and issued Spanish airworthiness directive 03/94, 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 a one-time 
inspection to detect cracking in the area where the center wing-to-
fuselage attachment fitting is located, and repair, if necessary. The 
proposed AD also would require installation of a reinforcing plate in 
the attachment area of the center wing-to-fuselage attachment fitting, 
after inspection and any necessary repairs have been accomplished. The 
installation of the reinforcing plate would be required to be 
accomplished in accordance with the applicable service bulletin 
described previously.

Differences Between the Proposed Rule and the Applicable Service 
Bulletin

    Operators should note that this proposed AD would require that a 
one-time visual inspection be conducted immediately prior to the 
installation of the reinforcing plate. Any necessary repairs would be 
required to be accomplished in a manner approved by the FAA. CASA 
Service Bulletins SB-235-53-20 and SB-235-53-20M do not provide for 
procedures for conducting such an inspection or necessary repairs.
    The FAA has determined that, due to the safety implications and 
consequences associated with fatigue cracking in this area, any such 
cracking must be repaired prior to further flight and the installation 
of the reinforcing plate.

Cost Impact

    The FAA estimates that 2 CASA Model CN-235 series airplanes of U.S. 
registry would be affected by this proposed AD.
    It would take approximately 25 work hours per airplane to 
accomplish the proposed actions, at an average labor rate of $60 per 
work hour. Required parts would cost approximately $645 per airplane. 
Based on these figures, the cost impact of the proposed AD on U.S. 
operator is estimated to be $4,290, or $2,145 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-126-AD.

    Applicability: Model CN-235 series airplanes; as listed in CASA 
Service Bulletin SB-235-53-20, Revision 2, dated June 9, 1994 (for 
non-military airplanes); and Service Bulletin SB-235-53-20M, 
Revision 1, dated November 27, 1995 (for military airplanes); 
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 (c) 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 area of the center wing-to-
fuselage attachment fitting, which consequently could reduce the 
structural integrity of this area, accomplish the following:

[[Page 9390]]

    (a) For non-military airplanes: Prior to the accumulation of 
17,000 total landings, accomplish the actions specified in 
paragraphs (a)(1), (a)(2), and (a)(3) of this AD:
    (1) Remove all parts and other items in the area of the center 
wing-to-fuselage attachment fitting, in accordance with Paragraph 
2.B. (``Removal'') of the Accomplishment Instructions of CASA 
Service Bulletin SB-235-53-20, Revision 2, dated June 9, 1994.
    (2) After all parts and other items have been removed in 
accordance with paragraph (a)(1) of this AD, conduct a visual 
inspection, using a magnifier of at least 10x magnitude, to detect 
fatigue cracking in this area (ref: Figure 1, Sheet 1, of the 
service bulletin). If any cracking is detected, prior to further 
flight and prior to installing the reinforcing plate in accordance 
with paragraph (a)(3) of this AD, repair in a manner approved by the 
Manager, Standardization Branch, ANM-113, FAA, Transport Airplane
    Directorate.
    (3) Install a reinforcing plate having CASA part number (P/N) 
35-25010-0101 in the attachment area of the center wing-to-fuselage 
attachment fitting, in accordance with the service bulletin.
    (b) For military airplanes: Prior to the accumulation of 15,000 
total landings, accomplish the actions specified in paragraphs 
(b)(1), (b)(2), and (b)(3) of this AD:
    (1) Remove all parts and other items in the area of the center 
wing-to-fuselage attachment fitting, in accordance with Paragraph 
2.B. (``Removal'') of the Accomplishment Instructions of CASA 
Service Bulletin SB-235-53-20M, Revision 1, dated November 27, 1995.
    (2) After all parts and other items have been removed in 
accordance with paragraph (b)(1) of this AD, conduct a visual 
inspection, using a magnifier of at least 10x magnitude, to detect 
fatigue cracking in this area (ref: Figure 1, Sheet 1, of the 
service bulletin). If any cracking is detected, prior to further 
flight and prior to installing the reinforcing plate in accordance 
with paragraph (b)(3) of this AD, repair in a manner approved by the 
Manager, Standardization Branch, ANM-113, FAA.
    (3) Install a reinforcing plate having CASA part number (P/N) 
35-25010-0101 in the attachment area of the center wing-to-fuselage 
attachment fitting, in accordance with the service bulletin.
    (c) 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. 
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, FAA, Transport 
Airplane Directorate.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (d) 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 25, 1997.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-5160 Filed 2-28-97; 8:45 am]
BILLING CODE 4910-13-U