[Federal Register Volume 64, Number 12 (Wednesday, January 20, 1999)]
[Proposed Rules]
[Pages 3052-3055]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-1182]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-219-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 certain CASA Model CN-235 series 
airplanes. This proposal would require a one-time visual inspection to 
detect relative movement or deformation of the joint areas of the rear 
attaching supports and lower skin of the left and right outer flaps; 
repetitive borescopic inspections to detect cracking of the spar and of 
the

[[Page 3053]]

rear internal support fittings of the outer flaps; and corrective 
actions, if necessary. This proposal also provides for optional 
terminating action for 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 detect and correct fatigue cracking of 
the rear internal support fittings of the outer flap structure, which 
could result in failure of the outer flaps, and consequent reduced 
controllability of the airplane.

DATES: Comments must be received by February 19, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-219-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 98-NM-219-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. 98-NM-219-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Direccion General de Aviacion Civil (DGAC), which is the 
airworthiness authority for Spain, notified the FAA that an unsafe 
condition may exist on certain CASA Model CN-235 series airplanes. The 
DGAC advises that, during routine maintenance on a Model CN-235 series 
airplane with a high number of flight cycles, relative displacement 
between the lower skin of the outer flap and the outer rear fittings of 
the outer flap was detected. Further inspection revealed that fatigue 
cracking had developed in the rear internal support fittings of the 
outer flap, which attaches the flap structure to the outer rear support 
fittings. Such fatigue cracking, if not detected and corrected, could 
result in failure of the outer flaps, and consequent reduced 
controllability of the airplane.

Explanation of Relevant Service Information

    CASA has issued Maintenance Instructions COM 235-123, Revision 01, 
dated October 7, 1997, which describes procedures for a one-time 
detailed visual inspection to detect relative movement or deformation 
of the joint areas of the rear attaching supports and lower skin of the 
left and right outer flaps, and repetitive borescopic inspections to 
detect cracking of the spar and of the rear internal support fittings 
of the outer flaps.
    CASA also has issued Service Bulletin SB-235-57-20, dated December 
23, 1997, which describes procedures for replacement of the left and 
right outer flaps with new, improved outer flaps that have modified 
rear internal support fittings installed. Accomplishment of this action 
will eliminate the need for the repetitive borescopic inspections of 
the replaced outer flap only, as described in CASA Maintenance 
Instructions COM 235-123, Revision 01, dated October 7, 1997.
    Accomplishment of the actions specified in CASA Maintenance 
Instructions COM 235-123, Revision 01, and CASA Service Bulletin SB-
235-57-20, is intended to adequately address the identified unsafe 
condition.
    The DGAC classified the CASA Maintenance Instructions COM 235-123, 
Revision 01, as mandatory and issued Spanish airworthiness directive 
10/97, dated March 19, 1997, 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 accomplishment of 
the actions specified in the maintenance instructions and the service 
bulletin described previously, except as discussed below.

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 airplanes, 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.
    The proposed AD also would differ from the Spanish airworthiness 
directive in that the latter document requires accomplishing the 
following actions prior to the accumulation of 4,000 total landings:

[[Page 3054]]

     A detailed visual inspection within 24 hours (after the 
receipt of the Spanish airworthiness directive); and
     A borescopic inspection within 10 days; and
     Repetitive borescopic inspections for any outer flap 
replaced with a new, improved outer flap within 4,000 landings and 
thereafter at intervals not to exceed 600 landings.
    In developing appropriate compliance times and repetitive intervals 
for this proposed AD, the FAA considered not only the manufacturer's 
recommendation, but the degree of urgency associated with addressing 
the subject unsafe condition, the average utilization of the affected 
fleet, and the time necessary to perform the visual inspection. In 
light of all of these factors, the FAA finds the following to be 
warranted prior to the accumulation of 4,000 total landings:
     A one-time detailed visual inspection within 30 days after 
the effective date of the AD; and
     If no relative movement or deformation is detected, a 
borescopic inspection within 300 landings after accomplishment of the 
visual inspection; and
     No repetitive inspections of an outer flap that is 
replaced with a new, improved outer flap.
    Operators should further note that, although CASA Maintenance 
Instructions COM 235-123, Revision 01, dated October 7, 1997, specify 
that the manufacturer may be contacted for disposition of certain 
cracking conditions, this proposed AD would require addressing those 
conditions by replacement of the outer flap with a new, improved outer 
flap in accordance with CASA Service Bulletin SB-235-57-20, dated 
December 23, 1997.

Cost Impact

    The FAA estimates that 2 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 1 work 
hour per airplane to accomplish the proposed visual inspection, at an 
average labor rate of $60 per work hour. Based on these figures, the 
cost impact of the visual inspection proposed by this AD on U.S. 
operators is estimated to be $120, or $60 per airplane.
    It would take approximately 4 work hours to accomplish the proposed 
borescopic inspection, at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of the borescopic inspection 
proposed by this AD on U.S. operators is estimated to be $480, or $240 
per airplane, per inspection cycle.
    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.
    Should an operator elect to accomplish the terminating action that 
is provided by this AD action, it would take approximately 30 work 
hours to accomplish, at an average labor rate of $60 per work hour. The 
cost of required parts would be approximately $123,204 per airplane. 
Based on these figures, the cost impact of the optional terminating 
action would be $125,004 per airplane.

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 98-NM-219-AD.

    Applicability: Model CN-235 series airplanes, as listed in CASA 
Service Bulletin SB-235-57-20, dated December 23, 1997; and Model 
CN-235 having 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 (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 detect and correct fatigue cracking of the rear internal 
support fittings of the outer flap structure, which could result in 
failure of the outer flaps, and consequent reduced controllability 
of the airplane, accomplish the following:
    (a) Prior to the accumulation of 4,000 total landings, or within 
30 days after the effective date of this AD, whichever occurs later, 
perform a one-time detailed visual inspection to detect relative 
movement or deformation of the joint areas of the rear attaching 
supports and lower skin of the left and right outer flaps, in 
accordance with CASA Maintenance Instructions COM 235-123, Revision 
01, dated October 7, 1997.
    (1) If no relative movement or deformation is detected: Within 
300 landings, perform the requirements of paragraph (b) of this AD.
    (2) If any relative movement or deformation is detected: Prior 
to further flight, perform the requirements of paragraph (b) of this 
AD.
    (b) Remove the rear support attach bolts, one at a time, and 
perform a borescopic inspection to detect cracking of the spar and 
of the rear internal support fittings of the outer flaps, in 
accordance with CASA Maintenance Instructions COM 235-123, Revision 
01, dated October 7, 1997.
    (1) If no crack is detected, repeat the borescopic inspection 
thereafter at intervals not to exceed 600 landings until the 
replacement specified in paragraph (c) of this AD is accomplished.
    (2) If any crack is detected, prior to further flight, replace 
the cracked outer flap with a new outer flap on which modified rear 
internal support fittings are installed, in accordance with CASA 
Service Bulletin SB-235-57-20, dated December 23, 1997. Such 
replacement constitutes terminating action for the repetitive 
borescopic inspection required by paragraph (b) of this AD for the 
replaced outer flap only.

[[Page 3055]]

    (c) Accomplishment of the replacement specified in CASA Service 
Bulletin SB-235-57-20, dated December 23, 1997, constitutes 
terminating action for the repetitive borescopic inspections 
required by paragraph (b) of this AD.
    (d) As of the effective date of this AD, no person shall install 
on any airplane an outer flap having part number 35-15501-00.
    (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, 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.

    (f) 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 01/97, dated March 19, 1997.

    Issued in Renton, Washington, on January 12, 1999.
Darrell M. Pederson,
 Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-1182 Filed 1-19-99; 8:45 am]
BILLING CODE 4910-13-P