[Federal Register Volume 63, Number 23 (Wednesday, February 4, 1998)]
[Proposed Rules]
[Pages 5763-5764]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-2643]


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 Proposed Rules
                                                 Federal Register
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
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  Federal Register / Vol. 63, No. 23 / Wednesday, February 4, 1998 / 
Proposed Rules  

[[Page 5763]]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-CE-30-AD]
RIN 2120-AA64


Airworthiness Directives; AlliedSignal Aerospace KT 76A Air 
Traffic Control (ATC) Transponders

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to adopt a new airworthiness directive 
(AD) that would apply to certain AlliedSignal Aerospace (AlliedSignal) 
KT 76A ATC transponders that are installed on aircraft. The proposed AD 
would require incorporating a modification on the affected transponders 
that consists of replacing two resistor network modules with glass-
coated modules. The proposed AD is the result of reports of these ATC 
transponders transmitting misleading encoding altimeter information to 
ground-based ATC radar sites and nearby Traffic Alert and Collision 
Avoidance System (TCAS)-equipped aircraft. The actions specified by the 
proposed AD are intended to prevent the transmission of misleading 
encoding altimeter information between affected aircraft caused by the 
inability of these ATC transponders to coordinate with ground-based ATC 
radar sites and nearby TCAS-equipped aircraft.

DATES: Comments must be received on or before April 10, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 97-CE-30-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106. Comments may be inspected at this location 
between 8 a.m. and 4 p.m., Monday through Friday, holidays excepted.
    Service information that applies to the proposed AD may be obtained 
from AlliedSignal Inc., General Aviation Avionics, 400 N. Rogers Road, 
Olathe, Kansas 66062-1212. This information also may be examined at the 
Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Mr. Roger A. Souter, Aerospace 
Engineer, Wichita Aircraft Certification Office, FAA, 1801 Airport 
Road, Mid-Continent Airport, Wichita, Kansas 67209; telephone: (316) 
946-4134; facsimile: (316) 946-4407.

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 should 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 that summarizes 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 No. 97-CE-30-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, Central Region, Office of the Regional Counsel, Attention: 
Rules Docket No. 97-CE-30-AD, Room 1558, 601 E. 12th Street, Kansas 
City, Missouri 64106.

Discussion

    Several customer complaints relating to the altitude reporting 
accuracy of AlliedSignal KT 76A ATC transponders; part number (P/N) 
066-1062-00/10/02; serial numbers 93,000 through 109,999, that are 
installed on aircraft prompted AlliedSignal to conduct testing of these 
transponder systems. From this testing, AlliedSignal identified that 
these ATC transponders are transmitting misleading encoding altimeter 
information to ground-based ATC radar sites and nearby TCAS-equipped 
aircraft.
    The condition is the result of ``silver migration'' on the 
substrate of a resistor network that is connected to the Gilham 
Altitude outputs of an external encoding altimeter. This creates low 
impedance paths between adjacent resistors in the network, which causes 
the transponder unit to incorrectly interpret the output of the 
encoding altimeter. Blocking diodes that are internal to the 
AlliedSignal KT 76A ATC transponders prevent this ``silver migration'' 
problem from affecting other users of the Gilham outputs.

Relevant Service Information

    AlliedSignal has issued Service Bulletin SB KT 76A-7, dated July 
1996, which includes procedures for replacing two resistor network 
modules, RM401 and RM402, with new glass-coated parts. When 
accomplished, this replacement is referred to as Mod 7.

The FAA's Determination

    After examining the circumstances and reviewing all available 
information related to the incidents described above, including the 
referenced service information, the FAA has determined that AD action 
should be taken to prevent the transmission of misleading encoding 
altimeter information between affected aircraft caused by the inability 
of these ATC transponders to coordinate with ground-based ATC radar 
sites and nearby TCAS-equipped aircraft.

Explanation of the Provisions of the Proposed AD

    Since an unsafe condition has been identified that is likely to 
exist or develop in airplanes that have AlliedSignal KT 76A ATC 
transponders; part number (P/N) 066-1062-00/10/02; serial numbers 
93,000 through 109,999, the FAA is proposing AD action. The

[[Page 5764]]

proposed AD would require replacing two resistor network modules, RM401 
and RM402, with new glass-coated parts. When accomplished, this 
replacement is referred to as Mod 7. Accomplishment of the proposed 
replacement would be required in accordance with AlliedSignal Service 
Bulletin SB KT 76A-7, dated July 1996.

Compliance Time of the Proposed AD

    The condition specified by the proposed AD is not caused by actual 
hours time-in-service (TIS) of the aircraft where the affected ATC 
transponders are installed. The need for the hardware modification has 
no correlation to the number of times the equipment is utilized or the 
age of the equipment. For this reason, the compliance time of the 
proposed AD is presented in calendar time instead of hours TIS.

Cost Impact

    The FAA estimates that 20,000 transponder units could be affected 
by the proposed AD if all were installed in aircraft of U.S. registry. 
Approximately 2 workhours would be needed to accomplish the proposed 
action, at an average labor rate of $60 an hour. Parts will be provided 
by AlliedSignal at no cost to the owners/operators of airplanes with 
the affected transponder units installed. Based on these figures, the 
total cost impact of the proposed AD on U.S. operators is estimated to 
be $2,400,000, or $120 per airplane.
    These figures are based on the presumption that all of the affected 
transponder units are installed in aircraft and the units do not 
incorporate Mod 7. AlliedSignal has informed the FAA that parts have 
been distributed to incorporate Mod 7 on approximately 300 transponder 
units. Presuming that each set of parts has been installed on an 
airplane equipped with one of the affected transponder units, the cost 
impact of the proposed AD would be reduced $36,000 from $2,400,000 to 
$2,364,000.

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 action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under 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 has been placed 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 a new airworthiness directive 
(AD) to read as follows:

AlliedSignal Inc.: Docket No. 97-CE-30-AD.

    Applicability: AlliedSignal KT 76A Air Traffic Control (ATC) 
transponders; part number (P/N) 066-1062-00/10/02; serial numbers 
93,000 through 109,999, as installed on, but not limited to the 
following airplanes (all serial numbers), certificated in any 
category:

    Cessna Aircraft Company: 172, 182, R182, T182, 206, P206, U206, 
TP206, 210, T210, P210, 310, E310, T310, and 421 series airplanes.
    Twin Commander Aircraft Company: 500, 520, 560, 680, 681, 685, 
690, 695, and 720 series airplanes.
    The New Piper Aircraft Corporation: PA-31, PA-32, and PA-34 
series airplanes.
    Raytheon Aircraft Company: E33, F33, G33, 35, J35, K35, L35, 
K35, M35, P35, S35, V35, 36, A26, B36, D55, E55, 56, A56, 58, 58A, 
95, B95, D95, and E95 series airplanes.
    Mooney Aircraft Corporation: M20 series airplanes.
    McDonnell Douglas Helicopter Company: Model 500N rotorcraft.

    Note 1: This AD applies to each airplane equipped with a 
transponder that is 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 request approval for an alternative method of 
compliance in accordance with paragraph (d) 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 within the next 6 months after the 
effective date of this AD, unless already accomplished.
    To prevent the transmission of misleading encoding altimeter 
information between affected aircraft caused by the inability of the 
affected ATC transponders to coordinate with ground-based air 
traffic control (ATC) radar sites and nearby Traffic Alert and 
Collision Avoidance System (TCAS)-equipped aircraft, accomplish the 
following:
    (a) Replace the two resistor network modules, RM401 and RM402, 
with new glass-coated parts in accordance with the MODIFICATION 
PROCEDURE section of AlliedSignal Service Bulletin SB KT 76A-7, 
dated July 1996. When accomplished, this replacement is referred to 
as Mod 7.
    (b) As of the effective date of this AD, no person may install 
an AlliedSignal KT 76A ATC transponder; part number (P/N) 066-1062-
00/10/02; serial numbers 93,000 through 109,999, in an aircraft 
without first incorporating Mod 7 as specified in paragraph (a) of 
this AD.
    (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) An alternative method of compliance or adjustment of the 
compliance time that provides an equivalent level of safety may be 
approved by the Manager, Wichita Aircraft Certification Office 
(ACO), 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, 
Kansas 67209. The request shall be forwarded through an appropriate 
FAA Maintenance Inspector, who may add comments and then send it to 
the Manager, Wichita ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Wichita ACO.

    (e) All persons affected by this directive may obtain copies of 
the document referred to herein upon request to AlliedSignal Inc., 
General Aviation Avionics, 400 N. Rogers Road, Olathe, Kansas 66062-
1212; or may examine this document at the FAA, Central Region, 
Office of the Regional Counsel, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.

    Issued in Kansas City, Missouri, on January 28, 1998.
Terry L. Chasteen,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-2643 Filed 2-3-98; 8:45 am]
BILLING CODE 4910-13-U