[Federal Register Volume 62, Number 92 (Tuesday, May 13, 1997)]
[Proposed Rules]
[Pages 26258-26261]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-12519]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-46-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 revising the Airplane Flight 
Manual (AFM) to include requirements for activation of the ice 
protection systems, and to add information regarding operation in icing 
conditions. This proposal also would require installing an ice detector 
system and revising the AFM to include procedures for testing system 
integrity. This proposal is prompted by reports indicating that 
flightcrews experienced difficulties controlling the airplane during 
(or following) flight in normal icing conditions, when the ice 
protection system either was not activated when ice began to accumulate 
on the airplane, or the ice protection system was never activated. 
These difficulties may have occurred because the flightcrews did not 
recognize that a significant enough amount of ice had formed on the 
airplane to require activation of the deicing equipment. The actions 
specified by the proposed AD are intended to ensure that the flightcrew 
is able to recognize the formation of significant ice accretion and 
take appropriate action; such formation of ice could result in reduced 
controllability of the airplane in normal icing conditions.

DATES: Comments must be received by June 24, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-46-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 Embraer, Empresa Brasileira De Aeronautica S/A, Sao Jose 
Dos Campos, Brazil. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; or at the FAA, Small Airplane Directorate, Atlanta Aircraft 
Certification Office, Campus Building, 1701 Columbia Avenue, Suite 2-
160, College Park, Georgia.

FOR FURTHER INFORMATION CONTACT: Carla Worthey, Aerospace 
Engineer,Systems and Flight Test Branch, ACE-116A, FAA, Small Airplane 
Directorate, Atlanta Aircraft Certification Office, Campus Building, 
1701 Columbia Avenue, Suite 2-160, College Park, Georgia 30337-2748; 
telephone (404) 305-7364; fax (404) 305-7348.

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.

[[Page 26259]]

    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 97-NM-46-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. 97-NM-46-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports indicating that the flightcrews of 
EMBRAER Model EMB-120 series airplanes experienced difficulties 
controlling the airplane during (or following) flight in normal icing 
conditions, when the ice protection system either was not activated 
when ice began to accumulate on the airplane, or the ice protection 
system was never activated. These difficulties may have occurred 
because the visual cues available to the flightcrew were not sufficient 
for the crew to recognize that enough ice had formed on the airplane to 
require activation of the deicing equipment. If the flightcrew is 
unable to recognize the formation of significant ice accretion [i.e., 
\1/4\- to \1/2\-inch on the wing leading edges, as specified in the 
original FAA-approved Airplane Flight Manual (AFM) guidelines] on the 
airplane, appropriate action would not be taken to activate the deicing 
equipment. This condition, if not corrected, could result in reduced 
controllability of the airplane in normal icing conditions.

FAA's Determinations

    The FAA is aware that, based on previous procedures provided to 
flightcrews of many airplanes equipped with deicing boots, a historical 
precedent has been set for waiting to activate the deicing equipment. 
In light of this information, and based on reports received, the FAA 
finds that certain procedures should be included in the Limitations and 
Normal Procedures Sections of the AFM for EMBRAER Model EMB-120 series 
airplanes. Additionally, an ice detector system should be installed on 
these airplanes to enable the flightcrew to more accurately determine 
the need to activate the ice protection systems on the airplane and to 
take appropriate action. The FAA has determined that such procedures 
must be included in the Limitations Section of the AFM for the affected 
airplanes to ensure that the flightcrew is aware of the potential 
hazard related to the formation of ice on the airplane, and of the 
procedures necessary to address it.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require revising the Limitations Section of the AFM 
to include requirements for activation of the ice protection systems, 
and for revising the Normal Procedures Section of the AFM to add 
information regarding operation in icing conditions. This proposal also 
would require installing an ice detector system and revising the Normal 
Procedures Section of the AFM to include procedures for testing system 
integrity. The installation would be required to be accomplished in 
accordance with a method approved by the FAA.

Explanation of Proposed Compliance Time for Installation

    Operators should note that paragraph (b) of this AD proposes a 
compliance time of 6 months for installation of an ice detector system. 
In developing an appropriate compliance time for this installation, the 
FAA considered not only the degree of urgency associated with 
addressing the subject unsafe condition, but the availability of 
required parts and the practical aspect of accomplishing the required 
installation within an interval of time that parallels normal scheduled 
maintenance for the majority of affected operators. The manufacturer 
has advised that an ample number of required parts will be available 
for installation of the ice detector systems on the U.S. fleet within 
the proposed compliance period.

Cost Impact

    There are approximately 282 EMBRAER Model EMB-120 series airplanes 
of the affected design in the worldwide fleet. The FAA estimates that 
220 airplanes of U.S. registry would be affected by this proposed AD.
    The FAA estimates that it would take approximately 1 work hour per 
airplane to accomplish the proposed AFM revisions, 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 estimated to be $13,200, 
or $60 per airplane.
    The FAA estimates that it would take approximately 60 work hours 
per airplane to accomplish the proposed installation, and that the 
average labor rate is $60 per work hour. Required parts would cost 
approximately $15,000 per airplane. Based on these figures, the cost 
impact of the proposed AD on U.S. operators is estimated to be 
$4,092,000, or $18,600 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.
    The FAA recognizes that the obligation to maintain aircraft in an 
airworthy condition is vital, but sometimes expensive. Because AD's 
require specific actions to address specific unsafe conditions, they 
appear to impose costs that would not otherwise be borne by operators. 
However, because of the general obligation of operators to maintain 
aircraft in an airworthy condition, this appearance is deceptive. 
Attributing those costs solely to the issuance of this AD is 
unrealistic because, in the interest of maintaining safe aircraft, 
prudent operators would accomplish the required actions even if they 
were not required to do so by the AD.
    A full cost-benefit analysis has not been accomplished for this 
proposed AD. As a matter of law, in order to be airworthy, an aircraft 
must conform to its type design and be in a condition for safe 
operation. The type design is approved only after the FAA makes a 
determination that it complies with all applicable airworthiness 
requirements. In adopting and maintaining those requirements, the FAA 
has already made the determination that they establish a level of 
safety that is cost-beneficial. When the FAA, as in this proposed AD, 
makes a finding of an unsafe condition, this means that the original 
cost-beneficial level of safety is no longer being achieved and that 
the proposed actions are necessary to restore that level of safety. 
Because this level of safety has already been determined to be cost-
beneficial, a full cost-benefit analysis for this proposed

[[Page 26260]]

AD would be redundant and unnecessary.

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:

Empresa Brasileira de Aeronautica, S.A. (Embraer): Docket 97-NM-46-
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 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 ensure that the flightcrew is able to recognize the formation 
of significant ice accretion, which could result in reduced 
controllability of the airplane in normal icing conditions, 
accomplish the following:
    (a) Within 30 days after the effective date of this AD, 
accomplish paragraphs (a)(1), (a)(2), and (a)(3) of this AD.
    (1) Revise the Limitations Section of the FAA-approved Airplane 
Flight Manual (AFM) to include the following requirements for 
activation of the ice protection systems. This may be accomplished 
by inserting a copy of this AD in the AFM.

    ``TURN ON ICE PROTECTION SYSTEM and IGNITION SWITCHES AS 
FOLLOWS:
     AOA, TAT, SLIP, and IGNITION SWITCHES:

--When atmospheric or ground icing conditions exist.

     PROPELLER:

--When atmospheric or ground icing conditions exist, OR
--At the first sign of ice formation anywhere on the aircraft.

     WING and TAIL LEADING EDGES, ENGINE AIR INLET, and 
WINDSHIELD:

--At the first sign of ice formation anywhere on the aircraft.

    Note: Atmospheric icing conditions exist when:
--Outside Air Temperature (OAT) during ground operations or Total 
Air Temperature (TAT) in flight is 10 degrees C or below; and
--Visible moisture in any form is present (such as clouds, fog with 
visibility of one mile or less, rain, snow, sleet, or ice crystals).

    Note: Ground icing conditions exist when:

--OAT during ground operations is 10 degrees C or below; and
--Surface snow, standing water, or slush is present on the ramps, 
taxiways, or runways.

    Note: For Operation in Atmospheric Icing Conditions:

--Follow the procedures in the Normal Procedures Section under 
Operation in Icing Conditions.''

    (2) Revise the Normal Procedures Section of the AFM by removing 
any icing procedures that contradict the procedures specified in 
paragraphs (a)(1) and (a)(3) of this AD from that section of the 
AFM. Where differences exist between the icing procedures specified 
in the Limitations and Normal Procedures Sections of the AFM, the 
procedures specified in the Limitations Section prevail.
    (3) Revise the Normal Procedures Section of the FAA-approved 
Airplane Flight Manual (AFM) to include the following additional 
information regarding operation in icing conditions. This may be 
accomplished by inserting a copy of this AD in the AFM.

    ``Under DAILY CHECKS of the Ice Protection System, add the 
following:
    Ice Detector System TEST Button (if installed)--PRESS Check 
normal test sequence.
    Under OPERATION IN ICING CONDITIONS for FLYING INTO NORMAL ICING 
CONDITIONS, add the following:

--During flight, monitoring for icing conditions should start 
whenever the outside air temperature is near or below freezing or 
when operating into icing conditions, as specified in the 
Limitations Section of this manual.
--When operating in icing conditions, the front windshield corners 
(unheated areas), propeller spinners, and wing leading edges will 
provide good visual cues of ice accretion.
--For airplanes equipped with an ice detection system, icing 
conditions also will be indicated by the illumination of the ICE 
CONDITION light on the multiple alarm panel.
--When flying into known or forecast icing conditions, proceed as 
follows:

IGNITION Switches--ON
Airspeed--160 KIAS MINIMUM

    If buffet onset occurs, increase airspeed.
    Holding configuration:

Landing Gear Lever--UP
Flap Selector Lever--UP
NP--85% MINIMUM

    Increase NP as required to eliminate propeller 
vibrations.
    Approach procedure:
    Increase approach speeds (according to the flap setting) by 10 
KIAS until landing is assured.

    Note: For airplanes equipped with an ice detection system, ice 
formation will be indicated by the ICE CONDITION light illumination 
on the multiple alarm panel.

    CAUTION: The ice protection systems must be turned on 
immediately when the ICE CONDITION light illuminates on the multiple 
alarm panel or when any ice accretion is detected by visual 
observation or other cues.
    CAUTION: Do not interrupt the automatic sequence of operation of 
the leading edge deice boots once it is turned ON. The system should 
be turned OFF only after leaving the icing conditions.''

    (b) Within 6 months after the effective date of this AD, install 
an ice detector in accordance with a method approved by the Manager, 
Atlanta Aircraft Certification Office (ACO), FAA, Small Airplane 
Directorate.
    (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, Atlanta ACO. Operators shall submit 
their requests through an appropriate FAA Principal Operations 
Inspector, who may add comments and then send it to the Manager, 
Atlanta ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of

[[Page 26261]]

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 May 7, 1997.
Neil D. Schalekamp,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-12519 Filed 5-12-97; 8:45 am]
BILLING CODE 4910-13-U