[Federal Register Volume 66, Number 82 (Friday, April 27, 2001)]
[Proposed Rules]
[Pages 21107-21110]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-10467]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-120-AD]
RIN 2120-AA64


Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. 
(EMBRAER) Model EMB-120 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 EMBRAER Model EMB-120 series 
airplanes. This proposal would require replacing certain existing 
potentiometers with recently manufactured potentiometers, modifying the 
flexible couplers that attach the shafts of the potentiometers to the 
shafts of the primary flight controls, performing repetitive 
calibration tests of the potentiometers and obtaining

[[Page 21108]]

repetitive readouts of the flight data recorder (FDR), and reporting 
the results to the FAA. This action is necessary to prevent the 
potentiometers that provide information on the positions of the primary 
flight controls to the FDR from transmitting noisy signals or becoming 
improperly calibrated, resulting in the transmission of incomplete or 
inaccurate data to the FDR. This lack of reliable data could hamper 
discovery of the unsafe condition which caused an accident or an 
incident and prevent the FAA from developing and mandating actions to 
prevent additional incidents or accidents caused by that same unsafe 
condition.

DATES: Comments must be received by May 29, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-120-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. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-120-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Empresa Brasileira de Aeronautica S.A. (EMBRAER), P.O. 
Box 343--CEP 12.225, Sao Jose dos Campos--SP, Brazil. This information 
may be examined at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington; or at the FAA, Atlanta Aircraft 
Certification Office, One Crown Center, 1895 Phoenix Boulevard, suite 
450, Atlanta, Georgia.

FOR FURTHER INFORMATION CONTACT: Rob Capezzuto, Aerospace Engineer, 
ACE-116A, FAA, Atlanta Aircraft Certification Office, One Crown Center, 
1895 Phoenix Boulevard, suite 450, Atlanta, Georgia 30349; telephone 
(770) 703-6071; fax (770) 703-6097.

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 action may be changed in 
light of the comments received.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    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 action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-120-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. 2000-NM-120-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Departmento de Aviacao Civil (DAC), which is the airworthiness 
authority for Brazil, notified the FAA that an unsafe condition may 
exist on certain EMBRAER Model EMB-120 series airplanes. The DAC 
advises that screws on flexible couplers that attach the shafts of the 
primary flight controls to the shafts of potentiometers may become 
loose. In this case, erroneous data may be transmitted from the primary 
flight controls--the ailerons, the elevators, and the rudder--to the 
flight data recorder (FDR). Therefore, the DAC has issued Brazilian 
airworthiness directive 97-08-01, dated August 29, 1997, requiring 
application of adhesive to the screws to lock them in place.
    In addition, an investigation of the FDR system indicated that 
these potentiometers were producing noisy signals. EMBRAER, the 
manufacturer of the airplanes, and Penny & Giles, the manufacturer of 
the potentiometers, have attributed the noisy signals to an oxide film 
which forms on the windings of the potentiometers, if the 
potentiometers are kept in storage for an extended time.
    Finally, investigation of various accidents and incidents has 
revealed that improperly operating potentiometers have prevented the 
recording of complete and accurate data which, in some cases, has 
prevented determination of the cause of an incident or accident.

FAA's Determination of Unsafe Condition

    This action is necessary to prevent the potentiometers that provide 
information on the positions of the primary flight controls to the FDR 
from functioning improperly, resulting in the transmission of 
incomplete or inaccurate data to the FDR. Improper functioning of the 
potentiometers does not directly affect the safety of the airplane on 
which they are located. However, should an airplane with improperly 
functioning potentiometers also have an unrelated unsafe condition 
which results in an incident or accident, the data retrieved from the 
FDR will be incomplete or inaccurate. This lack of reliable data could 
hamper discovery of the unsafe condition which caused the accident or 
incident and prevent the FAA from developing and mandating actions to 
prevent additional incidents or accidents caused by that same unsafe 
condition. Therefore, the FAA has determined that the proposed action 
is necessary.
    It should be noted that the purpose of this action is not to 
enhance the safety of the EMB-120, but rather to restore the level of 
safety provided by the originally approved FDR. Therefore, this AD is 
the appropriate regulatory vehicle to achieve this purpose.

Explanation of Relevant Service Information

    EMBRAER has issued Service Bulletin 120-31-0038, Change 02, dated 
June 25, 1998, which describes procedures for applying adhesive to the 
screws of the flexible couplers which attach the shafts of the 
potentiometers to the shafts of the primary flight controls to prevent 
them from becoming loose. The DAC classified this service bulletin as 
mandatory and issued Brazilian

[[Page 21109]]

Airworthiness Directive 97-08-01, dated August 29, 1997.

FAA's Conclusions

    This airplane model is manufactured in Brazil 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 DAC has kept the FAA informed of 
the situation described above. The FAA has examined the findings of the 
DAC, 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 improperly functioning potentiometers may prevent discovery 
of an unsafe condition 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 removing existing potentiometers and 
replacing them with recently-manufactured potentiometers, and 
performing repetitive testing of the calibration of the new 
potentiometers and obtaining repetitive readouts of the FDR. These 
actions would be required to be accomplished in accordance with the 
EMBRAER EMB-120 Maintenance Manual or the EMBRAER EMB-120 service 
bulletin described previously. In addition, the proposed AD would 
require submission of the results of the calibration tests and the FDR 
readouts to the FAA.

Differences Between Proposed AD and Brazilian Airworthiness 
Directive

    The Brazilian airworthiness directive requires only the application 
of adhesive over the threads of the screws of the flexible couplers 
which attach the shafts of the potentiometers to the shafts of the 
primary flight controls. The application is to be accomplished by the 
next ``A'' check or within the next 400 flight hours after the 
effective date of the AD, whichever occurs first.
    The proposed AD would also require replacing existing 
potentiometers for the primary flight controls with potentiometers that 
were recently manufactured, performing repetitive calibration tests of 
the potentiometers and obtaining repetitive readouts of the FDR, and 
submitting the results to the FAA. The compliance time proposed for 
these more extensive requirements is 6 months.

Interim Action

    This proposed AD is considered to be interim action. It would 
require operators to perform calibration tests of potentiometers and to 
obtain readouts of FDR's at intervals not to exceed 6 months and to 
submit reports of the results to the FAA for 2 years. The reports will 
be used to determine whether the proposed corrective actions adequately 
address the noisy signals, loose couplers, and incorrect calibrations 
which have been found. If they do not, the FAA may consider further 
rulemaking.

Cost Impact

    The FAA estimates that 250 airplanes of U.S. registry would be 
affected by this proposed AD and that the average labor rate is $60 per 
work hour. Based on these figures, the cost impact of the proposed AD 
on U.S. operators is as estimated in Table 1.

                  Table 1.--Estimated Cost Impact of AD
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                                Work     Cost of parts    Cost/airplane
           Action               hours      (in US $)        (in US $)
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Replacement of 3                   1.0  3,000..........            3,060
 potentiometers.
Application of adhesive.....       1.0  Negligible.....               60
Calibration of                     1.0  Negligible.....               60
 potentiometers.
Readout of FDR..............      33.0  Negligible.....            1,980
    Totals..................      36.0  3,000..........            5,160
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    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 proposed AD were not adopted. The cost impact 
figures discussed in AD rulemaking actions represent only the time 
necessary to perform the specific actions actually required by the AD. 
These figures typically do not include incidental costs, such as the 
time required to gain access and close up, planning time, or time 
necessitated by other administrative actions.

Regulatory Impact

    The regulations proposed herein would not have a substantial direct 
effect 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, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    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:

    Empresa Brasileira de Aeronautica S.A. (EMBRAER): Docket 2000-
NM-120-AD.

    Applicability: All Model EMB-120 series airplanes, certificated 
in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability

[[Page 21110]]

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 prevent the potentiometers that provide information on the 
positions of the primary flight controls to the flight data recorder 
(FDR) from transmitting noisy signals or becoming improperly 
calibrated, resulting in the transmission of incomplete or 
inaccurate data to the FDR, accomplish the following:

Replacement of Potentiometers

    (a) Within 6 months after the effective date of this AD: Replace 
potentiometers to the ailerons, elevators, and rudder with 
potentiometers that have a date of manufacture within 12 months 
preceding the date of installation, in accordance with Section 31-
30-05 of the EMBRAER EMB-120 Maintenance Manual, dated July 17, 
1998.

    Note 2: All potentiometers manufactured by Penny & Giles after 
January 1999 are date stamped.

Modification of Flexible Coupler

    (b) After accomplishment of paragraph (a) of this AD but prior 
to further flight: Apply locktite adhesive over the threads of the 
screws of the flexible couplers that attach the shafts of the 
potentiometers to the shafts of the primary flight controls, in 
accordance with EMBRAER Service Bulletin 120-31-0038, Change 02, 
dated June 25, 1998.

Calibration Tests and Readouts

    (c) After accomplishment of paragraphs (a) and (b) of this AD 
but prior to further flight: Perform calibration tests of the 
potentiometers to the ailerons, elevators, and rudder and obtain a 
readout of the FDR, in accordance with Section 31-30-00 of the 
EMBRAER EMB-120 Maintenance Manual, dated July 17, 1998. Repeat the 
calibration tests and obtain readouts at intervals not to exceed 6 
months until 2 years after the effective date of this AD.

Reporting Requirement

    (d) At the applicable time specified in paragraph (d)(1) or 
(d)(2) of this AD: Submit a report of the calibration tests of the 
potentiometers and the readouts of the FDR to the Manager, Atlanta 
Aircraft Certification Office (ACO), FAA, One Crown Center, 1895 
Phoenix Boulevard, suite 450, Atlanta, Georgia 30349; fax (770) 703-
6097. Information collection requirements contained in this 
regulation have been approved by the Office of Management and Budget 
(OMB) under the provisions of the Paperwork Reduction Act of 1980 
(44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 
2120-0056.
    (1) For calibration tests and readouts accomplished after the 
effective date of this AD: Submit the report within 30 days after 
performing the tests required by paragraph (c) of this AD.
    (2) For calibration tests and readouts accomplished prior to the 
effective date of this AD: Submit the report within 10 days after 
the effective date of this AD.

Alternative Methods of Compliance

    (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, Atlanta ACO. Operators shall submit 
their requests through an appropriate FAA Principal Maintenance 
Inspector, who may add comments and then send it to the Manager, 
Atlanta ACO.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Atlanta ACO.

Special Flight Permits

    (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 4: The subject of this AD is addressed in Brazilian 
airworthiness directive 97-08-01, dated August 29, 1997.


    Issued in Renton, Washington, on April 20, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-10467 Filed 4-26-01; 8:45 am]
BILLING CODE 4910-13-P