[Federal Register Volume 61, Number 206 (Wednesday, October 23, 1996)]
[Proposed Rules]
[Pages 54958-54960]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-27124]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-76-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 all CASA CN-235 series airplanes. 
This proposal would require repetitive eddy current inspections to 
detect fatigue cracks in the nose landing gear (NLG) turning tube, and 
replacement of cracked tubes. This proposal is prompted by a report of 
the failure of an NLG turning tube during landing roll; the failure was 
attributed to fatigue cracking in the turning tube. The actions 
specified by the proposed AD are intended to ensure that fatigue 
cracking in the NLG turning tube is detected and corrected before it 
could cause the failure of the tube and, consequently, degrade the 
structural integrity of the NLG.

DATES: Comments must be received by December 2, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-76-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 Number 96-NM-76-AD.'' The postcard will be date stamped and 
returned to the commenter.

[[Page 54959]]

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-76-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

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 all CASA Model CN-235 series airplanes. 
The DGAC advises that it received a report from one operator who 
experienced, during landing roll, the failure of the nose landing gear 
(NLG) turning tube. Investigation revealed that the failure was due to 
fatigue cracking in the turning tube. The tube had accumulated over 
8,600 landings. A subsequent inspection of the fleet revealed fatigue 
cracking in the NLG turning tubes on other airplanes; in each case, the 
tube had accumulated more than 8,000 landings. Such cracking, if not 
detected and corrected in a timely manner, could result in failure of 
the NLG turning tube. This situation could degrade the structural 
integrity of the NLG, and adversely effect landing operations.

Explanation of Relevant Service Information

    CASA has issued Maintenance Instructions COM 235-092, Revision No. 
2, dated May 5, 1995, which describes procedures for conducting 
repetitive high frequency eddy current (HFEC) inspections to detect 
fatigue cracking in the NLG turning tube. It also describes procedures 
for replacing cracked tubes with new units. The DGAC classified this 
service bulletin as mandatory and issued Spanish airworthiness 
directive 01/95, Revision 1, dated May 18, 1995, 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 repetitive eddy 
current inspections to detect fatigue cracking in the NLG turning tube. 
If any cracking is detected, the turning tube would be required to be 
replaced with a new unit prior to further flight. The actions would be 
required to be accomplished in accordance with the service bulletin 
described previously.

Interim Action

    This is considered interim action until final action is identified, 
at which time the FAA may consider further rulemaking.

Cost Impact

    The FAA estimates that 1 CASA Model CN-235 series airplane of U.S. 
registry would be affected by this proposed AD, that it would take 
approximately 8 work hours per airplane to accomplish the proposed 
actions, and that the average labor rate is $60 per work hour. Required 
parts would be provided by the manufacturer at no cost to operators. 
Based on these figures, the cost impact of the proposed AD on U.S. 
operators is estimated to be $480.
    The cost impact figure 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:

Casa: Docket 96-NM-76-AD.

    Applicability: All Model CN-235 series 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 
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 structural degradation of the nose landing gear (NLG) 
due to failure of the NLG turning tube, accomplish the following:
    (a) At the applicable time specified in either paragraph (a)(1) 
or (a)(2) of this AD, conduct a high frequency eddy current (HFEC) 
inspection to detect fatigue cracking in the NLG turning tube, in 
accordance with the procedures specified in Annex 1 and Annex 2 of 
CASA Maintenance Instructions COM 235-092, Revision No. 2, dated May 
5, 1995.
    (1) For Model CN-235 airplanes [Basic model; Maximum Takeoff 
Weight (MTOW)=31,746 lbs. (14,400 kgs.)]: Conduct the inspection 
prior to or upon the accumulation of 6,000 landings on the NLG 
turning tube, or within 50 landings after the effective date of this 
AD, whichever occurs later.

[[Page 54960]]

    (2) For Model CN-235-100 series airplanes [MTOW=33,290 lbs. 
(15,100 kgs.)] and Model CN-235-200 series airplanes [MTOW=34,833 
lbs. (15,800 kgs)]: Conduct the inspection prior to or upon the 
accumulation of 4,800 landings on the NLG turning tube, or within 50 
landings after the effective date of this AD, whichever occurs 
later.
    (b) If no cracking is detected during the inspection required by 
paragraph (a) of this AD, repeat the inspection thereafter at 
intervals not to exceed 200 landings.
    (c) If any cracking is detected during any inspection required 
by paragraph (a) or (b) of this AD, prior to further flight, replace 
the NLG turning tube with a new unit in accordance with CASA 
Maintenance Instructions COM 235-092, Revision No. 2, dated May 5, 
1995. After replacement, repeat the HFEC inspection prior to or upon 
the accumulation of 6,000 landings on the new NLG turning tube 
installed on Model CN-325 airplanes (basic model); or prior to or 
upon the accumulation of 4,800 landings on the new NLG turning tube 
installed on Model CN-325-100 and -200 series airplanes. Thereafter, 
repeat the inspection at intervals not to exceed 200 landings.
    (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, 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 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.

    (e) 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 October 16, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-27124 Filed 10-22-96; 8:45 am]
BILLING CODE 4910-13-U