[Federal Register Volume 62, Number 202 (Monday, October 20, 1997)]
[Rules and Regulations]
[Pages 54366-54368]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-27222]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-137-AD; Amendment 39-10159; AD 97-21-06]
RIN 2120-AA64


Airworthiness Directives; Construcciones Aeronauticas, S.A. 
(CASA) Model CN-235 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain CASA Model CN-235 series airplanes, that requires 
repetitive inspections of the torsion tubes and fittings of the 
elevator and rudder assemblies to detect stress corrosion cracking, and 
replacement of cracked parts. This action also requires accomplishment 
of a modification that constitutes terminating action for the 
repetitive inspections. This amendment is prompted by reports 
indicating that stress corrosion cracking in these parts has been found 
on some airplanes. The actions specified by this AD are intended to 
prevent loss of control of the elevator and/or rudder, due to failure 
of the elevator and/or rudder assemblies as a result of stress 
corrosion cracking.

DATES: Effective November 24, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 24, 1997.

ADDRESSES: The service information referenced in this AD may be 
obtained from Construcciones Aeronauticas, S.A., Getafe, Madrid, Spain. 
This information may be examined at the Federal Aviation Administration 
(FAA), Transport Airplane Directorate, Rules Docket, 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: Greg Dunn, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2799; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain CASA Model CN-235 series 
airplanes was published in the Federal Register on February 7, 1997 (62 
FR 5785). That action proposed to require repetitive inspections of the 
torsion tubes and fittings of the elevator and rudder assemblies to 
detect stress corrosion cracking, and replacement of discrepant parts. 
In addition, that action proposed to require eventual installation of 
newly designed torsion tube assemblies on all airplanes, which, when 
accomplished, would constitute terminating action for the required 
inspections.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were submitted in response 
to the proposal or the FAA's determination of the cost to the public.

Conclusion

    The FAA has determined that air safety and the public interest 
require the adoption of the rule as proposed.

Cost Impact

    The FAA estimates that 1 CASA Model CN-235 series airplane of U.S. 
registry will be affected by this AD.
    It will take approximately 6 work hours per airplane to accomplish 
each required visual inspection, at an average labor rate of $60 per 
work hour. Based on these figures, the cost impact of the required 
inspection on the single affected U.S. operator is estimated to be 
$360, per inspection cycle.
    It will take approximately 40 work hours to accomplish the required 
terminating modification, at an average labor rate of $60 per work 
hour. (The work hour figure does not include the time needed for 
preparation of the airplane or equipment; familiarization with the 
service bulletin; curing times for adhesive, sealant, paint, etc.; tool

[[Page 54367]]

collection; or down time). Required parts will cost approximately 
$8,900 per airplane. Based on these figures, the cost impact of the 
required modification on the single affected U.S. operator is estimated 
to be $11,300.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the 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 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.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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:

97-21-06  CASA: Amendment 39-10159. Docket 96-NM-137-AD.

    Applicability: CASA Model CN-235 airplanes; as listed in CASA 
Service Bulletin SB-235-27-05, Revision 1, dated September 29, 1993 
(non-military airplanes), and CASA Service Bulletin SB-235-27-05M, 
Revision 2, dated January 25, 1996 (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 (e) 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 loss of control of the elevator and/or rudder, due to 
failure of the elevator and/or rudder assemblies as a result of 
stress corrosion cracking in the torsion tubes and fittings, 
accomplish the following:

    Note 2: Actions required by this AD that were accomplished 
previous to the effective date of this AD, and in accordance with 
earlier versions of the specified CASA service bulletins, are 
considered acceptable for compliance with the applicable 
requirements of this AD.

    (a) At the applicable time specified in either paragraph (a)(1) 
or (a)(2) of this AD, conduct a visual inspection of the torsion 
(torsion) tubes on the elevator and rudder assemblies to detect 
stress corrosion cracking, in accordance with CASA Service Bulletin 
SB-235-27-05, Revision 1, dated September 29, 1993 (for non-military 
airplanes) or CASA Service Bulletin SB-235-27-05M, Revision 2, dated 
January 25, 1996 (for military airplanes), as applicable.
    (1) For airplanes that have accumulated more than 600 total 
hours time-in-service, or more than 1,000 total landings, as of the 
effective date of this AD: Conduct the inspection required by 
paragraph (a) of this AD prior to the accumulation of 50 hours time-
in-service, or 100 landings, or within 3 months, after the effective 
date of this AD, whichever occurs first.
    (2) For all other airplanes: Conduct the inspection required by 
paragraph (a) of this AD prior to the accumulation of 600 total 
hours time-in-service, or 1,000 total landings, or within 6 months, 
after the effective date of this AD, whichever occurs first.
    (b) If no cracking is detected during the inspection required by 
paragraph (a) of this AD, repeat that inspection at intervals not to 
exceed 600 hours time-in-service, or 1,000 landings, or 6 months, 
whichever occurs first.
    (c) If any cracking is detected during the inspection required 
by paragraph (a) of this AD, prior to further flight, accomplish 
either paragraph (c)(1) or (c)(2) of this AD.
    (1) Replace cracked parts with a new parts of the original 
design, in accordance with the service bulletin. After replacement, 
repeat the visual inspection required by paragraph (a) of this AD at 
intervals not to exceed 600 hours time-in-service, or 1,000 
landings, or 6 months, whichever occurs first. OR
    (2) Replace cracked parts with a newly-designed parts, in 
accordance with CASA Service Bulletin SB-235-27-05, Revision 1, 
dated September 29, 1993 (for non-military airplanes); or CASA 
Service Bulletin SB-235-27-05M, Revision 2, dated January 25, 1996 
(for military airplanes); as applicable. This replacement 
constitutes terminating action for the repetitive visual inspections 
of that part required by paragraph (b) of this AD.
    (d) Within 2 years after the effective date of this AD, replace 
all original design parts comprising the torsion tube assemblies on 
the elevator and rudder assemblies with newly-designed parts, in 
accordance with CASA Service Bulletin SB-235-27-05, Revision 1, 
dated September 29, 1993 (for non-military airplanes); or CASA 
Service Bulletin SB-235-27-05M, Revision 2, dated January 25, 1996 
(for military airplanes); as applicable. This action constitutes 
terminating action for the inspection requirements of this AD.
    (e) 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.

    (f) Special flight permits may be issued in accordance with 
sections 21.197 and P21.199 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.
    (g) The actions shall be done in accordance with CASA Service 
Bulletin SB-235-27-05, Revision 1, dated September 29, 1993; and 
CASA Service Bulletin SB-235-27-05M, Revision 2, dated January 25, 
1996; as applicable; which contain the specified effective pages:

[[Page 54368]]



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                                                              Revision level shown                              
 Service bulletin referenced and date        Page No.               on page              Date shown on page     
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SB-235-27-05, Revision 1, September    1, 2................  1....................  September 29, 1993.         
 29, 1993.                                                                                                      
                                       3-23................  Original.............  February 5, 1993.           
SB-235-27-05M, Revision 2, January     1...................  2....................  January 25, 1996.           
 25, 1996.                                                                                                      
                                       2-23................  Original.............  October 28, 1991.           
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    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 Construcciones Aeronauticas, 
S.A., Getafe, Madrid, Spain. 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 4: The subject of this AD is addressed in Spanish 
airworthiness directive 06/94, dated August 1994.

    (h) This amendment becomes effective on November 24, 1997.

    Issued in Renton, Washington, on October 8, 1997.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-27222 Filed 10-17-97; 8:45 am]
BILLING CODE 4910-13-U