[Federal Register Volume 64, Number 155 (Thursday, August 12, 1999)]
[Proposed Rules]
[Pages 43953-43955]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-20893]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-117-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 supersedure of an existing 
airworthiness directive (AD), applicable to all CASA Model CN-235 
series airplanes, that currently requires repetitive eddy current 
inspections to detect fatigue cracks in the nose landing gear (NLG) 
turning tube, and replacement of cracked tubes. This proposal would add 
a requirement for the replacement of the existing NLG turning tube 
constructed of aluminum alloy with a new NLG turning tube made of 
steel; such replacement would terminate the repetitive inspections. 
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 and failure of the NLG turning tube, which could 
result in reduced structural integrity of the NLG.

DATES: Comments must be received by September 13, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-117-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: 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 99-NM-117-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. 99-NM-117-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On January 15, 1997, the FAA issued AD 97-02-17, amendment 39-9902 
(62 FR 3994, January 28, 1997), applicable to all CASA Model CN-235 
series airplanes, to require repetitive eddy

[[Page 43954]]

current inspections to detect fatigue cracks in the nose landing gear 
(NLG) turning tube, and replacement of cracked tubes. That action was 
prompted by a report of the failure of a NLG turning tube during 
landing roll; the failure was attributed to fatigue cracking in the 
turning tube. The requirements of that 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.

Action Since Issuance of Previous Rule

    In the preamble to AD 97-02-17, the FAA indicated that the actions 
required by that AD were considered ``interim action'' until final 
action is identified, at which time the FAA may consider further 
rulemaking. The FAA now has determined that further rulemaking action 
is indeed necessary, and this proposed AD follows that determination.

Explanation of Relevant Service Information

    CASA has issued Service Bulletin 35-CSB-32-001, dated February 16, 
1999, which describes procedures for replacement of the existing NLG 
turning tube constructed of aluminum alloy with a new NLG turning tube 
made of steel. The Direccion General de Aviacion Civil (DGAC), which is 
the airworthiness authority for Spain, classified this service bulletin 
as mandatory and issued Spanish airworthiness directive 01/95, Rev. 2, 
dated February 15, 1999, 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 supersede AD 97-02-17, 
amendment 39-9902, to continue to require repetitive eddy current 
inspections to detect fatigue cracks in the nose landing gear (NLG) 
turning tube, and replacement of cracked tubes. The proposed AD would 
add a requirement to replace the existing NLG turning tube constructed 
of aluminum alloy with a new NLG turning tube made of steel, which 
would terminate the repetitive inspections.

Differences Between Proposed Rule and Related Service Information

    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.

Cost Impact

    The FAA estimates that 2 airplanes of U.S. registry would be 
affected by this proposed AD.
    The actions that are currently required by AD 97-02-17, and 
retained in this AD, take approximately 8 work hours per airplane to 
accomplish, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact of the currently required actions on 
U.S. operators is estimated to be $480 per airplane.
    The new actions that are proposed in this AD action would take 
approximately 16 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts would cost 
approximately $20,722 per airplane. Based on these figures, the cost 
impact of the proposed AD on U.S. operators is estimated to be $43,364, 
or $21,682 per airplane.
    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 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 removing amendment 39-9902 (62 FR 
3994, January 28, 1997), and by adding a new airworthiness directive to 
read as follows:

Construcciones Aeronauticas, S.A. (CASA): Docket 99-NM-117-AD. 
Supersedes AD 97-02-17, amendment 39-9902.

    Applicability: All Model CN-235 series airplanes; including 
Model CN-235 series airplane, 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 (f) of 
this AD. The request should include an assessment of the

[[Page 43955]]

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 and failure of the nose landing gear 
(NLG) turning tube, which could result in reduced structural 
integrity of the NLG, accomplish the following:

Restatement of Requirements of AD 97-02-17, Amendment 39-9902

    (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 02, 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 March 4, 1997 (the 
effective date of AD 97-02-17, amendment 39-9902), whichever occurs 
later.
    (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 March 4, 1997, 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 until the requirements of 
paragraph (d) are accomplished.
    (c) If any cracking is detected during any inspection required 
by paragraph (a) or (b) of this AD, prior to further flight, 
accomplish the actions required by paragraph (c)(1) or (c)(2) of 
this AD. After the effective date of this AD, only the actions 
specified by paragraph (c)(2) of this AD shall be accomplished.
    (1) Replace the NLG turning tube with a new unit in accordance 
with CASA Maintenance Instructions COM 235-092, Revision 02, 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.
    (2) Remove the NLG turning tube, P/N GA 63433, from the NLG yoke 
assembly and install a new turning tube, P/N GA 65924, and identify 
the modified NLG with a P/N SB-A0002-0101 data plate with the 
service bulletin number inscribed, in accordance with CASA Service 
Bulletin 35-CSB-32-001, dated February 16, 1999.

New Requirements of This AD

    (d) Remove the NLG turning tube, P/N GA 63433, from the NLG yoke 
assembly and install a new turning tube, P/N GA 65924, and identify 
the modified NLG with a P/N SB-A0002-0101 data plate with the 
service bulletin number inscribed, in accordance with CASA Service 
Bulletin 35-CSB-32-001, dated February 16, 1999. Except as provided 
by paragraph (c)(2) of this AD, accomplish the actions at the later 
of the times specified in paragraphs (d)(1) and (d)(2) of this AD. 
Accomplishment of these actions constitutes terminating action for 
the requirements of this AD.
    (1) Prior to the accumulation of 4,800 total flight cycles; or
    (2) Within 1 year or 200 landings after the effective date of 
this AD, whichever occurs first.
    (e) As of the effective date of this AD, no person shall install 
a NLG turning tube, P/N GA 63433, on any airplane.

Alternative Methods of Compliance

    (f) 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, 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, 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.

Special Flight Permits

    (g) 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.

    Note 3: The subject of this AD is addressed in Spanish 
airworthiness directive 01/95, Rev. 2, dated February 15, 1999.

    Issued in Renton, Washington, on August 6, 1999.
D. L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-20893 Filed 8-11-99; 8:45 am]
BILLING CODE 4910-13-U