[Federal Register Volume 59, Number 143 (Wednesday, July 27, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-18194]


[[Page Unknown]]

[Federal Register: July 27, 1994]


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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39 
[Docket No. 94-NM-83-AD] 
 

Airworthiness Directives; Aerospatiale Model ATR72-101, -102, -
201, and -202 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 Aerospatiale Model ATR72 
series airplanes. This proposal would require an inspection to 
determine the model and orientation of certain flight control rods, and 
replacement with modified rods, if necessary. This proposal is prompted 
by reports of corrosion found on the pitch and rudder trim and rudder 
travel limiter fail-safe rods. The actions specified by the proposed AD 
are intended to prevent problems associated with corrosion of the 
flight control rods, which could compromise the required strength of 
these items.

DATES: Comments must be received by September 6, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-83-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 Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex 
03, France. This information may be examined at the FAA, Transport 
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Sam Grober, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-1187; fax (206) 227-1100.

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 94-NM-83-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. 94-NM-83-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Direction General de l'Aviation Civile (DGAC), which is the 
airworthiness authority for France, recently notified the FAA that an 
unsafe condition may exist on certain Aerospatiale Model ATR72 series 
airplanes. The DGAC advises that corrosion has been detected on the 
pitch and rudder trim fail-safe rods and the rudder travel limiter 
fail-safe rods installed on these airplanes. (This corrosion was found 
during inspections that were conducted as a part of a sampling program 
carried out by the manufacturer.) In some cases, corrosion apparently 
was caused by water accumulating in the lower part of the rods and 
freezing; the rods in these cases were installed with their open end 
oriented upwards (rather than downwards), which allowed water to 
accumulate between the internal and external tubes of the rod. Some 
cracking was associated with corrosion in these cases. Such corrosion 
could compromise the required strength of these flight control rods.
    Aerospatiale has issued the following service bulletins which 
address the identified problems:
    a. Service Bulletin ATR72-27-1033, dated February 23, 1994, 
describes procedures for inspecting the elevator trim, rudder trim, and 
rudder travel limitation rods to determine the orientation of the open 
rod end. It also describes procedures for replacing rods having open 
ends that are oriented upwards with rods on which the open end of the 
rod is oriented downwards. A downward-oriented rod end will prevent the 
accumulation of water between the internal and external tubes of the 
rod. The DGAC classified the material contained in this service 
bulletin as mandatory and issued French Airworthiness Directive 94-001-
018(B), dated January 5, 1994, in order to assure the continued 
airworthiness of these airplanes in France.
    b. Service Bulletin ATR72-27-1012, Revision 3, dated October 7, 
1991, describes procedures for replacing the currently installed fail-
safe control rods with rods that have been modified by the addition of 
a drain hole in the non-open end of the rod and the application of a 
protective treatment. The DGAC has classified this service bulletin as 
``recommended.''
    c. Service Bulletin ATR72-27-1010, Revision 4, dated February 23, 
1994, describes procedures for reversing the installation of the ends 
of the elevator tab rod and rudder tab rod so that the open end of the 
rods is oriented downwards. The DGAC has classified this service 
bulletin as ``recommended.''
    d. Service Bulletin ATR72-27-1027, dated July 28, 1993, describes 
procedures for determining the installation direction of the fail-safe 
rod of the rudder travel limitation unit (TLU), and replacing the rod 
if it is installed with its open end oriented upwards. The DGAC has 
classified this service bulletin as ``recommended.''
    This airplane model is manufactured in France 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.
    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 an inspection to 
determine the orientation of the end of the pitch and rudder trim fail-
safe rods and the rudder travel limiter fail-safe rods, and replacement 
of those rods having downwards-oriented ends. The actions would be 
required to be accomplished in accordance with the service bulletins 
described previously.
    Airplanes on which Aerospatiale Modification 02723 and Modification 
03110 have been installed are not affected by the requirements of this 
proposed AD. The subject flight control rods on those airplanes have 
been modified prior to airplane delivery.
    The FAA estimates that 28 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 6 work 
hours per airplane to accomplish the proposed inspection actions, and 
that the average labor rate is $55 per work hour. Based on these 
figures, the total cost impact of the proposed AD on U.S. operators is 
estimated to be $9,240, or $330 per airplane. This total 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.
    Should replacement of any of the flight control rods be necessary, 
the number of work hours and the cost of required parts would vary 
according to the type of replacement accomplished. In a ``worst case 
scenario'' (all subject rods needing replacement), the cost of parts 
would be approximately $8,200 per airplane. Labor necessary to 
accomplish replacement of a rod(s) would vary from 2 work hours to 10 
work hours, at an average labor rate of $55 per work hour.
    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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Aerospatiale: Docket 94-NM-83-AD.

    Applicability: Model ATR72-101, -102, -201, and -202 series 
airplanes; as listed in Aerospatiale Service Bulletin ATR72-27-1033, 
dated February 23, 1994; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent problems associated with corrosion of the flight 
control rods, which could compromise the required strength of these 
items, accomplish the following:

    Note 1: Rods replaced and installed in accordance with the 
instructions of any version of Aerospatiale Service Bulletin ATR72-
27-1010 prior to the effective date of this AD are not affected by 
the requirements of this AD.

    (a) For airplanes having Manufacturer's Serial Numbers (MSN) 126 
through 183, inclusive: Within 18 months after the effective date of 
this AD, visually inspect the elevator trim fail-safe rods to 
determine the model and the orientation of the open end of the rod, 
in accordance with Part A of Aerospatiale Service Bulletin ATR72-27-
1033, dated February 23, 1994.
    (1) If a SARMA-type rod is installed, prior to further flight, 
replace that rod with a modified rod, in accordance with 
Aerospatiale Service Bulletin ATR72-27-1012, Revision 3, dated 
October 7, 1991.
    (2) If a TAC-type rod is installed, and if the open end of the 
rod is oriented in any direction other than downwards, prior to 
further flight, accomplish the reverse installation procedures 
specified in Aerospatiale Service Bulletin ATR72-27-1010, Revision 
4, dated February 23, 1994.
    (b) For airplanes having MSN's 126 through 198, inclusive, 204, 
and 207: Within 18 months after the effective date of this AD, 
visually inspect the rudder trim fail-safe rods to determine the 
model and the orientation of the open end of the rod, in accordance 
with Part B of Aerospatiale Service Bulletin ATR72-27-1033, dated 
February 23, 1994.
    (1) If a SARMA-type rod is installed, prior to further flight, 
replace that rod with a modified rod, in accordance with 
Aerospatiale Service Bulletin ATR72-27-1012, Revision 3, dated 
October 7, 1991.
    (2) If a TAC-type rod is installed, and if the open end of the 
rod is oriented in any direction other than downwards, prior to 
further flight, accomplish the reverse installation procedures 
specified in Aerospatiale Service Bulletin ATR72-27-1010, Revision 
4, dated February 23, 1994.
    (c) For airplanes having MSN's 198, and 126 through 237, 
inclusive: Within 18 months after the effective date of this AD, 
visually inspect the rudder travel limitation unit fail-safe rods to 
determine the model and the orientation of the open end of the rod, 
in accordance with Part C of Aerospatiale Service Bulletin ATR72-27-
1033, dated February 23, 1994.
    (1) If a SARMA-type rod is installed, prior to further flight, 
replace that rod with a new rod in accordance with Aerospatiale 
Service Bulletin ATR72-27-1027, dated July 28, 1993.
    (2) If a TAC-type rod is installed at the rudder travel 
limitation rod location, and if the open end of the rod is oriented 
in any direction other than downwards, prior to further flight, 
inspect that rod in accordance with Aerospatiale Service Bulletin 
ATR72-27-1027, dated July 28, 1993.
    (i) If no crack(s), deformation, or corrosion of the rod is 
found, prior to further flight, reinstall the rod so that the open 
end is oriented downwards, in accordance with the service bulletin.
    (ii) If any crack(s), deformation, or corrosion of the rod is 
found, prior to further flight, replace the rod with a modified rod 
in accordance with the service bulletin.
    (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 
Sec. Sec. 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 July 20, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-18194 Filed 7-26-4; 8:45 am]
BILLING CODE 4910-13-U