[Federal Register Volume 61, Number 19 (Monday, January 29, 1996)]
[Rules and Regulations]
[Pages 2699-2701]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-1571]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-270-AD; Amendment 39-9495; AD 95-26-15]


Airworthiness Directives; Allied Signal Commercial Avionics 
Systems CAS-81 Traffic Alert and Collision Avoidance Systems (TCAS) as 
Installed in, but Not Limited to, Various Transport Category Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This document publishes in the Federal Register an amendment 
adopting an airworthiness directive that was sent previously by 
individual letters to all known U.S. owners and operators of various 
transport category airplanes equipped with Allied Signal Commercial 
Avionics Systems CAS-81 TCAS. This amendment is prompted by reports of 
failure of the audio output of the CAS-81 TCAS. This AD requires a 
revision to the Airplane Flight Manual to provide the flightcrew with 
procedures to cycle power to the TCAS processor via the circuit breaker 
or power bus, and to perform a TCAS functional test to verify proper 
operation of the TCAS. The actions specified by this AD are intended to 
ensure that the flightcrew is advised of the potential hazard 
associated with failure of the audio output of the CAS-81 TCAS, and of 
the procedures necessary to address it.

DATES: Effective February 5, 1996.
    Comments for inclusion in the Rules Docket must be received on or 
before March 29, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-270-AD, 1601 Lind Avenue SW., Renton, 
Washington 98055-4056.
    This information concerning this amendment may be obtained from or 

[[Page 2700]]
    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, Suite 2-160, 
1701 Columbia Avenue, College Park, Georgia.

FOR FURTHER INFORMATION CONTACT: David Gollings, Flight Test Pilot, 
Systems and Flight Test Branch, ACE-116A, FAA, Atlanta Aircraft 
Certification Office, Campus Building, Suite 2-160, 1701 Columbia 
Avenue, College Park, Georgia 30337-2748; telephone (404) 305-7370; fax 
(404) 305-7348.

SUPPLEMENTARY INFORMATION: On December 26, 1995, the FAA issued 
priority letter AD 95-26-15, applicable to Allied Signal Commercial 
Avionics Systems CAS-81 Traffic Alert and Collision Avoidance Systems 
(TCAS) that are installed in, but not limited to, various transport 
category airplanes. That action requires a revision to the FAA-approved 
Airplane Flight Manual (AFM) to provide the flightcrew with procedures 
to cycle power to the TCAS processor via the circuit breaker or power 
bus, and to perform a TCAS functional test to verify proper operation 
of the TCAS. That action was prompted by reports of failure of the 
audio output of the CAS-81 TCAS.
    During bench testing, the parts manufacturer identified a capacitor 
in the audio output circuit that continued to build charge as long as 
the system was powered. The capacitor biases the audio circuit and 
causes failure of the audio output. The absence of audio output can 
occur after the TCAS has been powered without interruption for 
approximately 12 hours. Power interrupts (intentional or unintentional) 
tend to relieve the failure condition by causing the capacitor to 
discharge. This condition, if not corrected, could result in a critical 
reduction of the reliability of the CAS-81 TCAS to perform its 
collision avoidance function.
    Since the unsafe condition described is likely to exist or develop 
on other airplanes of the same type design, the FAA issued priority 
letter AD 95-26-15 to ensure that the flightcrew is advised of the 
potential hazard associated with failure of the audio output of the 
CAS-81 TCAS, and of the procedures necessary to address it. The AD 
requires a revision to the AFM to provide the flightcrew with 
procedures to cycle power to the TCAS processor via the circuit breaker 
or power bus prior to the first flight of the day, prior to the 
accumulation of 10 hours of uninterrupted power, and at the mid-point 
of any one flight scheduled to exceed 10 hours. Additionally, the AD 
requires that, prior to taxi before takeoff, a functional test must be 
accomplished to verify proper operation of the TCAS.
    Since it was found that immediate corrective action was required, 
notice and opportunity for prior public comment thereon were 
impracticable and contrary to the public interest, and good cause 
existed to make the AD effective immediately by individual letters 
issued on December 26, 1995, to all known U.S. owners and operators of 
various transport category airplanes equipped with Allied Signal 
Commercial Avionics Systems CAS-81 TCAS. These conditions still exist, 
and the AD is hereby published in the Federal Register as an amendment 
to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to 
make it effective to all persons.
    This is considered to be interim action. The manufacturer has 
advised that it currently is developing a modification that will 
positively address the unsafe condition addressed by this AD. Once this 
modification is developed, approved, and available, the FAA may 
consider additional rulemaking.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 95-NM-270-AD.'' The postcard will be date stamped and 
returned to the commenter.
    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, may be obtained from 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.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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.
    
[[Page 2701]]



Sec. 39.13  [Amended]

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

95-26-15 Allied Signal Commercial Avionics Systems: Amendment 39-
9495 Docket 95-NM-270-AD.

    Applicability: All CAS-81 Traffic Alert and Collision Avoidance 
Systems (TCAS) that are installed in, but not limited to, the 
following airplanes, certificated in any category:

Aerospatiale Models ATR42 and ATR72 series airplanes;
Airbus Industries Models A300, A310, and A340 series airplanes;
Beech Models 1900 and BE-65 through -90 (inclusive) series 
airplanes;
Boeing Models 727-100, 727-200, 737-200, 737-300, 737-400, 737-500, 
747-100, 747-200, 747-300, 747-400, 747SP, 757-200, 767-200, and 
767-300 series airplanes;
Convair Model CV-580 airplanes;
de Havilland Model DHC-7 series airplanes and Model DHC-8-100 
airplanes;
EMBRAER Model EMB-120 series airplanes;
Fairchild Model F227 airplanes;
Fokker Models F28 Mark 100, Mark 1000, and Mark 4000 series 
airplanes;
General Dynamics Models Convair 340 and 440 airplanes;
Gulfstream Models G-159 and G-IV airplanes;
Lockheed Model L-1011 series airplanes;
McDonnell Douglas Models DC-8-60, DC-9-31, DC-9-51, DC-10-10, DC-10-
30, DC-10-30F, MD-11, and MD-80 series airplanes;
Rockwell International NA-265-65 airplanes;
Saab Model 340 series airplanes; and
Shorts Model 360 series airplanes.

    Note 1: This AD applies to, but is not limited to, each airplane 
identified in the preceding applicability 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 use the 
authority provided in paragraph (b) of this AD to request approval 
from the FAA. This approval may address either no action, if the 
current configuration eliminates the unsafe condition; or different 
actions necessary to address the unsafe condition described in this 
AD. Such a request should include an assessment of the effect of the 
changed configuration on the unsafe condition addressed by this AD. 
In no case does the presence of any modification, alteration, or 
repair remove any affected airplane from the applicability of this 
AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To ensure that the flightcrew is advised of the potential hazard 
associated with failure of the audio output of the CAS-81 TCAS, and 
of the procedures necessary to address it, accomplish the following:
    (a) Within 3 calendar days after receipt of this AD, revise the 
Limitations Section of the FAA-approved Airplane Flight Manual (AFM) 
to include the following. This may be accomplished by inserting a 
copy of this AD in the AFM.
    ``In order to ensure that the audio output of the CAS-81 TCAS 
operates properly, accomplish the following:
     Prior to the first flight of the day; prior to the 
accumulation of 10 hours of uninterrupted power; and at the mid-
point of any one flight scheduled to exceed 10 hours: Cycle the 
power to the TCAS processor via the circuit breaker or power bus.
     Prior to taxi before takeoff: Initiate the TCAS 
functional test in accordance with AFM procedures to verify 
operational condition of the CAS-81 TCAS.''
    (b) 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, FAA, Atlanta Aircraft Certification 
Office. 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 compliance with this AD, if any, may be 
obtained from the Atlanta ACO.

    (c) 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.
    (d) This amendment becomes effective on February 5, 1996.

    Issued in Renton, Washington, on January 22, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-1571 Filed 1-26-96; 8:45 am]
BILLING CODE 4910-13-U