[Federal Register Volume 62, Number 33 (Wednesday, February 19, 1997)]
[Proposed Rules]
[Pages 7378-7380]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-3966]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-144-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 disabling the brake control 
valve of the

[[Page 7379]]

propeller. This proposal also would require that, prior to restoring 
propeller brake operation, the propeller brake control unit be replaced 
with a certain new propeller brake control unit. This proposal is 
prompted by reports of uncommanded activation of the propeller brake 
system on in-service airplanes during flight, due to the existing 
design of the brake control valve. The actions specified by the 
proposed AD are intended to prevent in-flight uncommanded activation of 
the propeller brake system, which could result in in-flight shutdown of 
the engine.

DATES: Comments must be received by March 31, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-144-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-144-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-103, Attention: Rules 
Docket No. 96-NM-144-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 certain CASA Model CN-235, CN-235-100, 
and CN-235-200 series airplanes. The DGAC advises that it has received 
reports of uncommanded activation of the propeller brake system on CASA 
Model CN-235 series airplanes during flight. Investigation revealed 
that the existing design of the brake control valve of the propeller 
can cause such a malfunction, including failure of the low pressure 
warning system during ground operation. This condition, if not 
corrected, could result in the in-flight shutdown of an engine.

Explanation of Relevant Service Information

    CASA has issued Communication COM 235-82, Revision 3, dated January 
31, 1995, which describes procedures for disabling the brake control 
valve of the propeller.
    CASA also has issued Service Bulletin SB-235-61-01, dated October 
11, 1994, and Service Bulletin SB-235-61-01M, Revision 2, dated January 
25, 1996 (for military airplanes). These service bulletins describe 
procedures for replacement of the propeller brake control unit, having 
part number (P/N) HP1410100-5 or HP1410100-7, with a new propeller 
brake control unit, having P/N HP1410100-9. This installation is to be 
performed prior to restoring propeller brake operation.
    The DGAC classified these service bulletins as mandatory and issued 
Spanish airworthiness directive 01/94 R1, dated July 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, first, disabling 
the brake control valve of the propeller. Then, prior to restoring 
propeller brake operation, the proposed AD would require replacement of 
certain propeller brake control units with certain new propeller brake 
control units. The actions would be required to be accomplished in 
accordance with the service bulletins described previously.

Cost Impact

    The FAA estimates that 2 CASA Model CN-235 series airplanes of U.S. 
registry would be affected by this proposed AD.
    It would take approximately 3 work hours per airplane to accomplish 
the proposed disabling of the brake control valve, at an average labor 
rate of $60 per work hour. Based on these figures, the cost impact of 
this proposed action on U.S. operators is estimated to be $360, or $180 
per airplane.
    It would take approximately 8 work hours per airplane to accomplish 
the proposed replacement, at an average labor rate of $60 per work 
hour. Required parts would be supplied by the manufacturer at no cost 
to the operators. Based on these figures, the cost impact of this 
proposed action on U.S. operators is estimated to be $960, or $480 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

[[Page 7380]]

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 96-NM-144-AD.

    Applicability: All Model CN-235, CN-235-100, and CN-235-200 
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 
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 (c) 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 in-flight uncommanded activation of the propeller 
brake system, which could result in in-flight shutdown of the 
engine, accomplish the following:
    (a) Within 10 days after the effective date of this AD, disable 
the brake control valve of the propeller in accordance with Annex 1 
of CASA Communication COM 235-82, Revision 3, dated January 31, 
1995.
    (b) Prior to restoring propeller brake operation, replace the 
propeller brake control unit having part number (P/N) HP1410100-5 or 
HP1410100-7, with a new propeller brake control unit having P/N 
HP1410100-9, in accordance with CASA Service Bulletin SB-235-61-01, 
dated October 11, 1994; or CASA Service Bulletin SB-235-61-01M, 
Revision 2 (for military airplanes), dated January 25, 1996; as 
applicable. Accomplishment of this replacement constitutes 
terminating action for the requirements of paragraph (a) of this AD.
    (c) 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.

    (d) 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 February 11, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-3966 Filed 2-18-97; 8:45 am]
BILLING CODE 4910-13-U