[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