Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model EMB-120 Series Airplanes, 5070-5073 [05-1795]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 70, Number 20 (Tuesday, February 1, 2005)]
[Proposed Rules]
[Pages 5070-5073]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-1795]


-----------------------------------------------------------------------

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 (FAA), Department of 
Transportation (DOT).

ACTION: Supplemental notice of proposed rulemaking; reopening of 
comment period.

-----------------------------------------------------------------------

SUMMARY: This document revises an earlier proposed airworthiness 
directive (AD), applicable to certain EMBRAER Model EMB-120 series 
airplanes that would have required initial and repetitive calibration 
testing of potentiometers to detect noisy signals and replacement of 
only those with noisy signals. This new action revises the proposed AD 
by reducing the compliance time for the repetitive calibration testing 
of the potentiometers and adding the requirement for reporting results 
of the calibration tests of the potentiometers and the readouts of the 
flight data recorder (FDR) to the airplane manufacturer. The actions 
specified by this new proposed AD are intended 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 that caused an accident or incident 
and prevent the FAA from developing and mandating actions to prevent 
additional accidents or incidents caused by that same unsafe condition. 
This action is intended to address the identified unsafe condition.

DATES: Comments must be received by February 28, 2005.

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 a.m. and 3 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: 
9-anm-nprmcomment@faa.gov. 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 or 2000 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 Federal Aviation Administration (FAA), Transport 
Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Todd Thompson, Aerospace Engineer, 
International Branch, ANM-116, Transport Airplane Directorate, 1601 
Lind Avenue, S.W., Renton, Washington, 98055-4056; telephone (425) 227-
1175; 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 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

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to add an airworthiness directive (AD), applicable to 
certain EMBRAER Model EMB-120 series airplanes, was published as a 
supplemental notice of proposed rulemaking (NPRM) in the Federal 
Register on March 19, 2003 (68 FR 13239), hereafter referred to as the 
``first supplemental NPRM.'' That supplemental NPRM would have required 
initial and repetitive calibration testing of the potentiometers to 
detect noisy signals and replacement of only those with noisy signals. 
Potentiometers that provide information on the positions of the primary 
flight controls to the flight data recorder (FDR) transmitting noisy 
signals or becoming improperly calibrated, if not corrected, could 
result in the transmission of incomplete or inaccurate data to the FDR. 
This lack of reliable data could hamper discovery of the unsafe 
condition that caused an accident or incident and prevent the FAA from 
developing and mandating actions to prevent additional accidents or 
incidents caused by that same unsafe condition.

[[Page 5071]]

Comments Received to the First Supplemental NPRM

    Due consideration has been given to the comments received in 
response to the first supplemental NPRM.

Request To Reduce Compliance Time

    The commenter, the National Transportation Safety Board (NTSB), 
requests that the compliance time interval for the repetitive 
calibration tests of the potentiometers and the readouts of the FDR in 
the first supplemental NPRM be changed from 12 months back to the 6 
months proposed in the original NPRM. The commenter states that it 
closed Safety Recommendation A-96-34 in 1998 with an acceptable status, 
because the original NPRM and the FAA Flight Standards Handbook 
Bulletin for Airworthiness 97-14 (EMBRAER EMB-120 Flight Data Recorder 
Test), directed potentiometer calibration testing every 6 months. Since 
the original NPRM was issued, the commenter points out that the FAA 
reversed its position on these inspections by proposing to require 
annual inspections in the first supplemental NPRM. The commenter states 
it has found sensor failures to be intermittent and believes that, 
because annual inspections are the typical inspection cycle for FDR 
systems, they may not reveal a problem and will not provide timely 
feedback on the effectiveness of the corrective action, possibly 
resulting in a failed sensor remaining in place for a full year.
    The FAA agrees. Sensor failures can be intermittent; therefore, we 
have determined that annual inspections--the typical inspection cycle 
for FDR systems--may not reveal a problem in a timely manner and could 
possibly result in a failed sensor remaining in place for up to a year. 
We have revised paragraph (b) of this second supplemental NPRM to 
reduce the compliance time interval for the repetitive calibration 
tests of the potentiometers and the readouts of the FDR from 12 months 
back to 6 months.

Request To Include Reporting Requirement

    The same commenter states that, if the AD is revised as proposed in 
the first supplemental NPRM, the only way to properly evaluate the 
effectiveness of the proposed corrective action is to require an FDR 
readout and evaluation every 6 months for 2 years, and to submit the 
results to the FAA for evaluation (as prescribed in the original NPRM). 
The commenter further asserts that removal of the reporting requirement 
will eliminate the opportunity for a fleet wide evaluation of the 
continuing problem.
    From these statements, we infer that the commenter is requesting 
that we revise the first supplemental NPRM to again require operators 
to report results of their calibration tests of the potentiometers and 
the readouts of the FDR to us every 6 months for 2 years. We partially 
agree with the commenter's request. As we explained previously, we have 
reduced the compliance time for the repetitive interval for the 
calibration tests of the potentiometers and the readouts of the FDR 
from 12 months to 6 months. We also agree that the calibration testing 
and readout results will be valuable for determining whether the 
proposed corrective actions adequately address the noisy signals, loose 
couplers, and incorrect calibrations that are found, and for 
determining the extent of these in the affected fleet. Based on the 
results of these reports, we may determine that further corrective 
action is warranted. Therefore, we have revised this second 
supplemental NPRM to add new a paragraph (f) that would require 
operators to report results of the initial and repetitive calibration 
tests of the potentiometers and the readouts of the FDR at intervals 
not to exceed 6 months for 24 months, and reidentified subsequent 
paragraphs accordingly.
    However, we do not agree that these results should be submitted to 
the FAA. The airplane manufacturer, EMBRAER, continually monitors the 
effectiveness of corrective actions and reviews both the corrective 
actions and their effectiveness with the Centro Technico Aeroespacial 
(CTA), which is a division of the airworthiness authority for Brazil, 
during quarterly service difficulty reviews. Therefore, we have 
determined that the calibration testing and readouts of the FDR should 
be reported directly to EMBRAER. We will work closely with EMBRAER and 
the CTA to monitor the effectiveness of the corrective actions 
specified in this second supplemental NPRM and will determine if 
further corrective action is warranted based on the results of these 
reports. No additional change to the second supplemental NPRM is 
necessary in this regard.

Request To Revise the Method of Compliance

    The same commenter requests that the first supplemental NPRM be 
revised to include requirements to conduct the FDR readout and 
evaluation just before the airplane's scheduled maintenance, with 
emphasis on observing parameter performance during in-flight and ground 
operations. The commenter further suggests that the most direct way to 
detect a sensor failure or out-of-calibration condition would be for a 
qualified analyst to periodically evaluate the FDR data, conduct a 
calibration check, and make any necessary sensor replacements during 
scheduled maintenance. The commenter asserts that the fact that one or 
more flight control parameters failed in 16 of 17 Model EMB-120 FDR 
readouts since 1990 suggests that the problem may be systemic and may 
require a more robust sensor and/or installation. Further, the 
commenter expresses doubt that all of the failures were caused by 
storing the sensors for more than 12 months, which the airplane and 
sensor manufacturers claim caused an oxide film to form on the sensor, 
resulting in the noisy signals. The commenter supplied no data to 
support this request.
    We do not agree with the commenter's request to revise the 
compliance method. However, as we explained previously, we have reduced 
the compliance time for the repetitive interval for calibration testing 
of the potentiometers and readout of the FDR. We find that installation 
problems with the sensor's compatibility with the installation 
environment would more likely appear as (hard) sensor failures, not 
signal quality problems. The commenter itself points out that noisy 
signals are rare and most service problems are related to poor 
maintenance or an improperly executed FD replacement. Therefore, 
because the potentiometers are sealed and require no maintenance, we 
still consider oxide coating inside the potentiometers a contributing 
factor to the source of the noisy signals--most likely a result of 
prolonged disuse of the sensors. Therefore, we find that these proposed 
corrective actions will purge any faulty sensors and that no change to 
the second supplemental NPRM is necessary in this regard.

Clarification of Certain Terms

    We have added a new Note 1 to this second supplemental NPRM (and 
re-numbered subsequent notes accordingly) to clarify our use of the 
word ``calibration.'' For the purposes of this second supplemental 
NPRM, we define calibration as the adjustment of the potentiometers, 
including operational and functional tests of the FDR system, as 
specified in Section 31-30-00 of the EMBRAER EMB120 Airplane 
Maintenance Manual (AMM).
    Paragraph (a) of this second supplemental NPRM provides procedures 
for a noise ``check'' to detect potentiometers with noisy signals. We 
have determined that certified

[[Page 5072]]

maintenance personnel must perform the noise check.

Explanation of Additional Changes to the Second Supplemental NPRM

    We have added a new paragraph (e) to this second supplemental NPRM 
(and reidentified subsequent paragraphs accordingly) to state that 
modification of the flexible couplings done before the effective date 
of this AD in accordance with Change 01 of EMBRAER Service Bulletin 
120-31-0038, dated October 3, 1997, is considered acceptable for 
compliance with the corresponding action required by paragraph (d) of 
this second supplemental NPRM.
    We have also changed paragraphs (a) and (c) of this second 
supplemental NPRM to specify that the proposed actions shall be done in 
accordance with a method approved by the Manager, International Branch, 
ANM-116, Transport Airplane Directorate, FAA. In addition, the 
following sections of the EMBRAER EMB-120 AMM are identified as 
approved methods of compliance for accomplishing the proposed actions 
specified in the applicable paragraphs:
     Paragraph (a): Section 31-30-00, dated April 10, 2002.
     Paragraph (c): Section 31-30-05, dated July 17, 1998.
    Additionally, we have added a new Note 2 to this second 
supplemental NPRM (and re-numbered subsequent notes accordingly) to 
clarify that Section 31-30-05 of the EMBRAER EMB120 AMM includes 
instructions for calibrating the potentiometers (adjusting the 
potentiometers, including operational and functional tests of the FDR 
system). The procedures for that calibration are specified in Section 
31-30-00 of the EMBRAER EMB120 AMM.

Conclusion

    Since some of these changes expand the scope of the first 
supplemental NPRM, the FAA has determined that it is necessary to 
reopen the comment period to provide additional opportunity for public 
comment.

Changes to 14 CFR part 39/Effect on the Proposed AD

    On July 10, 2002, the FAA issued a new version of 14 CFR part 39 
(67 FR 47997, July 22, 2002), which governs the FAA's airworthiness 
directives system. The regulation now includes material that relates to 
altered products, special flight permits, and alternative methods of 
compliance (AMOC). Because we have now included this material in part 
39, only the office authorized to approve AMOCs is identified in each 
individual AD. Therefore, paragraph (g) has been revised and paragraph 
(h) and Notes 1 and 4 of the first supplemental NPRM have been removed 
from this supplemental NPRM.

Increase in Labor Rate

    After the first supplemental NPRM was issued, we reviewed the 
figures we use to calculate the labor rate to do the required actions. 
To account for various inflationary costs in the airline industry, we 
find it appropriate to increase the labor rate used in these 
calculations from $60 per work hour to $65 per work hour. The economic 
impact information, below, has been revised to reflect this increase in 
the specified hourly labor rate.

Cost Impact

    The FAA estimates that 587 airplanes of U.S. registry would be 
affected by this proposed AD. The following table provides the 
estimated costs for U.S. operators to comply with this proposed AD.

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                            Average
                                                             labor      Cost of parts per
              Action                      Work hours        rate per        airplane          Cost per airplane
                                                              hour
----------------------------------------------------------------------------------------------------------------
Calibration and FDR readout, per    1 per potentiometer          $65  Negligible..........  $65, potentiometer
 calibration cycle (3                (for digital-type                                       (for digital-
 potentiometers per airplane).       FDRs), per                                              calibration type
                                     calibration cycle;                                      FDRs), per
                                     or 25 per                                               calibration cycle;
                                     potentiometer (for                                      or $1,625, per
                                     tape-type FDRs), per                                    potentiometer (for
                                     calibration cycle.                                      tape-type FDRs),
                                                                                             per calibration
                                                                                             cycle.
Application of adhesive...........  1....................         65  Negligible..........  $65.
----------------------------------------------------------------------------------------------------------------

    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. 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.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed above, I certify that the 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. Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities

[[Page 5073]]

under the criteria of the Regulatory Flexibility Act.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD. See the ADDRESSES section for a location 
to examine the regulatory evaluation.

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: Model EMB-120 series airplanes), certificated in 
any category, that are required by 14 CFR 135 to operate with a 
flight data recorder (FDR).
    Compliance: Required as indicated, unless accomplished 
previously.
    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, accomplish the following:

Initial Potentiometer Calibration Testing and FDR Readout

    (a) Within 6 months after the effective date of this AD: 
Calibrate the potentiometers to the ailerons, elevators, and rudder; 
perform a noise check of the potentiometers; and obtain a readout of 
the FDR; in accordance with a method approved by the Manager, 
International Branch, ANM-116, Transport Airplane Directorate, FAA. 
Section 31-30-00, dated April 10, 2002, of the EMBRAER EMB-120 
Airplane Maintenance Manual (AMM) is one approved method. The noise 
check must be performed by certificated maintenance personnel.

    Note 1: For the purposes of this AD, calibration is defined as 
the adjustment of the potentiometers, including operational and 
functional tests of the FDR system, as specified in Section 31-30-00 
of the EMBRAER EMB120 AMM.

Repetitive Potentiometer Calibration Testing and FDR Readout

    (b) Repeat the calibration and noise check of the potentiometers 
and obtain a readout of the FDR, as required by paragraph (a) of 
this AD, at intervals not to exceed 6 months.

Replacement of Potentiometers

    (c) If any readout of the FDR, conducted in accordance with 
paragraph (a) or (b) of this AD, indicates a potentiometer with a 
noisy signal: Within 20 days after obtaining the readout, replace 
the potentiometer with one that has a date of manufacture no greater 
than 12 months from the date of installation, in accordance with a 
method approved by the Manager, International Branch, ANM-116, 
Transport Airplane Directorate, FAA. Section 31-30-05, dated July 
17, 1998, of the EMBRAER EMB-120 AMM is one approved method.

    Note 2: Section 31-30-05 of the EMBRAER EMB120 AMM includes 
instructions for calibrating the potentiometers. The procedures for 
the calibration are specified in Section 31-30-00 of the EMB120 AMM.

Modification of Flexible Couplers

    (d) Prior to further flight, after accomplishing paragraph (a) 
of this AD: 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, dated February 
22, 1997; or Change 02, dated June 25, 1998.

Modification Accomplished Per Previous Issue of Service Bulletin

    (e) Modification of the flexible couplers done before the 
effective date of this AD in accordance with EMBRAER Service 
Bulletin 120-31-0038, Change 01, dated October 3, 1997, is 
considered acceptable for compliance with the corresponding action 
specified in paragraph (d) of this AD.

Reporting Requirement

    (f) At the applicable time specified in paragraph (f)(1) or 
(f)(2) of this AD: Submit a report of the calibration tests of the 
potentiometers and the readouts of the FDR to Empresa Brasileira de 
Aeronautica S.A. (EMBRAER), Certification--Continued Airworthiness, 
Av. Brig. Faria Lima, 2170, P.C. 179, 12227-901, Sao Jose dos 
Campos--SP, Brazil; fax (12) 3927-1184. 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, noise checks, and FDR readouts done 
after the effective date of this AD: Submit the report within 30 
days after performing each test, check, and readout required by 
paragraphs (a) and (b) of this AD.
    (2) For calibration tests, noise checks, and FDR readouts done 
before to the effective date of this AD: Submit the report within 10 
days after the effective date of this AD.

Alternative Methods of Compliance

    (g) In accordance with 14 CFR 39.19, the Manager, International 
Branch, ANM-116, Transport Airplane Directorate, FAA, is authorized 
to approve alternative methods of compliance for this AD.

    Note 3: The subject of this AD is addressed in Brazilian 
airworthiness directive 97-08-01, dated August 29, 1997.


    Issued in Renton, Washington, on January 21, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-1795 Filed 1-31-05; 8:45 am]
BILLING CODE 4910-13-P