[Federal Register Volume 63, Number 126 (Wednesday, July 1, 1998)]
[Rules and Regulations]
[Pages 35787-35790]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-17301]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-CE-30-AD; Amendment 39-10637; AD 98-14-03]
RIN 2120-AA64
Airworthiness Directives; AlliedSignal Inc. KT 76A Air Traffic
Control (ATC) Transponders
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD) that
applies to certain AlliedSignal Inc. (AlliedSignal) KT 76A ATC
transponders that are installed on aircraft. This AD requires
incorporating a modification on the affected transponders that consists
of replacing two resistor network modules with glass-coated modules.
This 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 this 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: Effective August 16, 1998.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of August 16, 1998.
ADDRESSES: Service information that applies to this AD may be obtained
from AlliedSignal Inc., General Aviation Avionics, 400 N. Rogers Road,
Olathe, Kansas 66062-1212. This information may also be examined at 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; or at the Office of
the Federal Register, 800 North Capitol Street, NW, suite 700,
Washington, DC.
[[Page 35788]]
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:
Events Leading to the Issuance of This AD
A proposal to amend part 39 of the Federal Aviation Regulations (14
CFR part 39) to include an AD that would apply to certain AlliedSignal
KT 76A ATC transponders that are installed on aircraft was published in
the Federal Register as a notice of proposed rulemaking (NPRM) on
February 4, 1998 (63 FR 5763). The NPRM proposed to require replacing
two resistor network modules, RM401 and RM402, with new glass-coated
parts. Accomplishment of the proposed action as specified in the NPRM
would be in accordance with AlliedSignal Service Bulletin SB KT 76A-7,
dated July 1996.
The NPRM was 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.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
Comment Issue: The Compliance Time Should Be Extended
Three commenters believe that the proposed compliance time of 6
calendar months is unrealistic. These comments are detailed as follows:
1. One commenter states that, in order to accomplish the work,
Allied Signal would have to supply 38 repairmen who would work 8 hours
per day for 6 months. The commenter questions whether this commitment
will be made.
2. Another commenter agrees with the FAA's decision to state the
compliance in calendar time, but believes that a more appropriate and
more convenient time would be to require the work at the next annual
inspection or transponder system inspection. This would reduce the
down-time for the affected aircraft by allowing the work to be
accomplished during regularly scheduled maintenance.
3. The third commenter states that many of the affected
transponders will be part of a complete pitot-static system that
requires biennial calibration in accordance with Sec. 91.413 of the
Federal Aviation Regulations (14 CFR 91.413). The commenter proposes
that since the unit will already be at the avionics shop for this
calibration, then the FAA should write the compliance time to coincide
with the biennial pitot-static system calibration.
The FAA partially concurs with the above comments, as follows:
1. After re-evaluating all information related to this subject, the
FAA concurs that 6 calendar months is an unrealistic time period to
have the work accomplished on all of the affected transponders. The FAA
believes that a large number of the affected aircraft already have the
proposed modification incorporated on the transponder. Based on all
information, the FAA believes that a 12 calendar month compliance time
is more realistic. The final rule will reflect this change.
2. The 12 calendar month compliance time will allow the
modification to be incorporated during the airplane's next annual
inspection, as requested by the commenter.
3. Because the silver migration process is affected by
environmental factors as well as occurring over time, the FAA cannot
predict when a particular transponder could fail. A transponder could
work well one day and then fail the next day. With this in mind, the
FAA does not concur that the compliance time should be written to
coincide with the next pitot-static system biennial calibration in
accordance with Sec. 91.413 of the Federal Aviation Regulations (14 CFR
91.413). This could allow the condition defined in this AD to go
undetected for up to 24 months.
Comment Issue: Problem Occurs Only on Aircraft Operating Above
10,000 Feet and the AD Should Be Limited to Only Those Aircraft
Operating in Instrument Flight Rule (IFR) Conditions
Two commenters believe that the condition specified in the NPRM is
associated with ``at altitude'' operations over time. The commenters
state that one could imply that:
``aircraft in the high altitude structure may be more likely to
experience this problem than one operating below 10,000 feet and
using the Allied Signal KT 76A ATC transponder simply because the
aircraft operates within Class B or C airspace or within a 30
nautical miles ``veil'' for a class B airport. The problem with an
erroneous altitude report from a high speed aircraft operating in
the IFR airspace system is significantly different than a small
airplane flying in visual flight rules (VFR) conditions.''
Both commenters recommend different actions than are already
proposed based on the above information and both believe that the
private operator (who is mostly a Sunday pilot) would remove the
equipment from the aircraft since aircraft in VFR operation outside of
the B and C airspace do not need to have a transponder unit. Both
believe that removing the transponder would reduce safety. These
recommendations are as follows:
1. One commenter suggests that those operating in only VFR
conditions fabricate and install a placard with the words ``For VFR Use
Only''. If or when these aircraft's transponders no longer comply with
the 125-foot error requirement of part 43, Appendix E, of the Federal
Aviation Regulations (14 CFR part 43, Appendix E), then the commenter
proposes that the AD require immediate replacement or modification of
the transponder equipment. The commenter feels that this would allow
thousands of small aircraft to fly legally and safely within the 30
nautical mile veils associated with Class B airports, without incurring
an additional expense to their flying activities.
2. The other commenter recommends that the FAA not issue the
proposed AD as a final rule, or if issued, limit the Applicability of
the AD to only turbine-powered or ``10-or-more seats'' aircraft. This
commenter feels that replacing equipment that meets performance
standards because of a ``maybe'' malfunction (which will simply cause
an error in altitude reporting) is wrong when it comes to private
aircraft (used mostly for pleasure). The commenter also suggests a
possible mandatory replacement or modification of the equipment if a
certain error is detected.
The FAA does not concur with the proposed alternatives presented by
the commenters. The altitude at which an aircraft equipped with one of
the affected transponders is flown and the amount of time flown at this
altitude do not affect the probability of the unit failing. The
``silver migration'' process occurs regardless of the altitude or the
time ``at altitude''. This ``silver migration'' process is slow and is
affected by environmental factors as well. The FAA cannot assure that
any given unit would not be affected by this condition during any given
2 year period. A unit could pass on one day and then fail the next day.
Aircraft that are operated in VFR conditions are interrogated by TCAS-
equipped aircraft in the areas. The ATC system and misleading aircraft
altitude information could represent a hazard to the aircraft in VFR
conditions. The FAA has determined that safety would be compromised if
the AD allowed, for aircraft operating in VFR conditions, the
[[Page 35789]]
system to fail before mandating replacement or modification.
Comment Issue: Limit the AD to Only Those Aircraft Exhibiting
Problems
In addition to the comments above proposing replacement or
modification of the Allied Signal KT 76A ATC transponder upon condition
for aircraft operating in VFR conditions, one commenter proposes that
the AD only apply to those transponders that exhibit problems during
the 24 calendar month pitot-static system calibration in accordance
with Sec. 91.413 of the Federal Aviation Regulations (14 CFR 91.413).
This would be for all transponders regardless of the type of operation
in which the aircraft is involved. The commenter believes that this
would accomplish the intent of the AD without burdening operators
already in good working order.
The FAA does not concur. As discussed earlier, the FAA cannot
predict when a particular transponder could fail. A transponder could
work well one day and then fail the next day. The FAA has determined
that safety would be compromised if the AD allowed the system to fail
before mandating replacement or modification.
Comment Issue: Wait for Results of Technical Field Study on
Transponders
One commenter agrees with the FAA that the KT 76A ATC transponders
have a demonstrated history of inaccurate or misleading data
transmission and that corrective action is necessary to address this
issue. This commenter goes on to state that the FAA Technical Center in
Atlantic City conducted a full-scale field study of transponder
performance in general aviation aircraft and determined that a variety
of deficiencies exist in a broad range of transponders, including the
KT 76A ATC transponders. This commenter suggests that the FAA withhold
issuance of this AD until the full scope of the transponder issues can
be addressed, including the problems associated with ``silver
migration'' in the KT 76A ATC transponders.
The FAA concurs that the information from the Technical Center
Study is very important. However, correspondence received from the
Technical Center indicates that resolution of these issues may take a
considerable amount of time. As stated earlier, the FAA cannot predict
when a particular transponder could fail. A transponder could work well
one day and then fail the next day. The FAA has determined that safety
would be compromised if the AD was not issued awaiting a resolution
from the FAA Technical Center in Atlantic City, regarding the full
scope of the transponder issues.
Comment Issue: Certain Aspects Not Covered in the Cost Impact
Four commenters propose changes to the section that describes the
cost impact upon the public. These include:
--It will take 2.5 workhours to accomplish the action instead of 2
workhours as presented in the NPRM;
--In addition to providing parts at no charge, Allied Signal is
providing warranty credit for up to 2.5 workhours to accomplish the
action;
--The cost impact should include the costs of a recalibration of the
pitot-static system; and
--The cost impact does not take into account the costs the affected
aircraft operators will incur while their aircraft is out-of-service.
The FAA concurs that it will take 2.5 workhours to accomplish the
action and that Allied Signal will provide warranty credit for up to
2.5 workhours to accomplish the action. The final rule will incorporate
this information.
The FAA does not concur that the cost impact section should account
for recalibration costs because the inputs affected by the silver
migration are encoding altimeter inputs and are not directly connected
to the pitot static system. Therefore, there are no costs associated
with pitot static system when complying with this AD.
The FAA believes that the change in the compliance time from 6
calendar months to 12 calendar months will take into account the cost
impact of aircraft ``out-of-service.'' This will allow the operator to
schedule the replacement and modification to coincide with a regularly
schedule maintenance event, thus, the AD will not necessitate any
additional downtime. Even if additional downtime is necessary for some
airplanes, the FAA does not possess sufficient information to evaluate
the number of airplanes that may be so affected or the amount of
additional downtime that may be required.
Comment Issue: Include Statistical Data Concerning the Problem in
the AD
One commenter states that including statistical data that more
fully discusses the origin of the ``silver migration'' problem would be
helpful.
The FAA, in working with the manufacturer, saw a three-fold
increase in the usage of spare parts of the Allied Signal KT76A ATC
transponders. Between the last quarter of 1995 and the first quarter of
1996, quarterly usage of spare parts increased from approximately 40
parts per quarter to approximately 120 parts for that quarter. This
indicates a significant trend and failure analysis of these
transponders. Information submitted to the FAA revealed that this
increase in spare parts usage was due to the ``silver migration''
problem. Within a 3-month period, over 150 of these transponder units
were in the repair shops to have ``silver migration'' problems
remedied.
Comment Issue: Concur With the Action
One commenter agrees with the proposal as written and states that
accomplishing ``this relatively inexpensive and simple repair action
will eliminate the potential hazard and enhance general flying safety
in the National Airspace System.''
The FAA's Determination
After careful review of all available information related to the
subject presented above, the FAA has determined that air safety and the
public interest require the adoption of the rule as proposed except for
the change in the compliance time and minor editorial corrections. The
FAA has determined that this change and minor corrections will not
change the meaning of the AD and will not add any additional burden
upon the public than was already proposed.
Cost Impact
The FAA estimates that 20,000 transponder units could be affected
by this AD if all were installed in aircraft of U.S. registry.
Approximately 2.5 workhours will be needed to accomplish this action,
at an average labor rate of $60 an hour. However, Allied Signal will
provide warranty credit for up to 2.5 workhours to accomplish the
action, as well as providing all necessary parts at no cost to the
owners/operators of airplanes with the affected transponder units
installed. Based on these figures and Allied Signal's warranty program,
this AD will impose no cost impact on U.S. operators of the affected
aircraft.
Regulatory Impact
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.
[[Page 35790]]
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) 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 final 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, Incorporation by
reference, 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.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive
(AD) to read as follows:
98-14-03 AlliedSignal Inc.: Amendment 39-10637; 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, 06, P206, U206,
TP206, 210, T210, P210, 310, 310, 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 aircraft 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
aircraft 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 12 calendar 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, M401 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
Secs. 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) The replacement required by this AD shall be done in
accordance with AlliedSignal Service Bulletin SB KT 76A-7, dated
July 1996. This incorporation by reference was approved by the
Director of the Federal Register in accordance with 5 U.S.C. 552(a)
and 1 CFR part 51. Copies may be obtained from AlliedSignal Inc.,
General Aviation Avionics, 400 N. Rogers Road, Olathe, Kansas 66062-
1212. Copies may be inspected at the FAA, Central Region, Office of
the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City,
Missouri, or at the Office of the Federal Register, 800 North
Capitol Street, NW, suite 700, Washington, DC.
(f) This amendment becomes effective on August 16, 1998.
Issued in Kansas City, Missouri, on June 23, 1998.
Marvin R. Nuss,
Acting Manager, Small Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 98-17301 Filed 6-30-98; 8:45 am]
BILLING CODE 4910-13-U
