Document ID: FAA-2010-1204-0019
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: Aviation Communication and Surveillance Systems Traffic Alert and Collision Avoidance System Units
Posted Date: 2011-10-07T04:00Z

[Federal Register Volume 76, Number 195 (Friday, October 7, 2011)]
[Proposed Rules]
[Pages 62321-62327]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-26084]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-1204; Directorate Identifier 2010-NM-147-AD]
RIN 2120-AA64

Airworthiness Directives; Aviation Communication & Surveillance 
Systems (ACSS) Traffic Alert and Collision Avoidance System (TCAS) 
Units

AGENCY: Federal Aviation Administration (FAA), DOT.

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

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SUMMARY: We are revising an earlier proposed airworthiness directive 
(AD) for certain Aviation Communication & Surveillance Systems (ACSS) 
traffic alert and collision avoidance system (TCAS) units installed on 
but not limited to various transport and small airplanes. That NPRM 
proposed to require upgrading software. That NPRM was prompted by 
reports of anomalies with TCAS units during a flight test over a high 
density airport. The TCAS units dropped several reduced surveillance 
aircraft tracks because of interference limiting. This action revises 
that NPRM by proposing to require new updated software for certain TCAS 
units. We are proposing this supplemental NPRM to correct the unsafe 
condition on these products. Since these actions impose an additional 
burden over that proposed in the NPRM, we are reopening the comment 
period to allow the public the chance to comment on these proposed 
changes.

DATES: We must receive comments on this supplemental NPRM by November 
7, 2011.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.
     Hand Delivery: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590,

[[Page 62322]]

between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays.
    For service information identified in this AD, contact Aviation 
Communication & Surveillance Systems, LLC, 19810 North 7th Avenue, 
Phoenix, Arizona 85027-4741; phone: 623-445-7040; fax: 623-445-7004; e-
mail: 3com.com">acss.orderadmin@L-3com.com; Internet: http://www.acss.com. You 
may review copies of the referenced service information at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington. For information on the availability of this material at the 
FAA, call 425-227-1221.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Office (phone: 800-647-5527) is in the ADDRESSES 
section. Comments will be available in the AD docket shortly after 
receipt.

FOR FURTHER INFORMATION CONTACT: Abby Malmir, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130L, FAA, Los Angeles Aircraft 
Certification Office (ACO), 3960 Paramount Boulevard, Lakewood, 
California 90712-4137; phone: 562-627-5351; fax: 562-627-5210; e-mail: 
abby.malmir@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2010-1204; 
Directorate Identifier 2010-NM-147-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    We issued an NPRM to amend 14 CFR part 39 to include an AD that 
would apply to Aviation Communication & Surveillance Systems (ACSS) 
traffic alert and collision avoidance system (TCAS) units with part 
numbers identified in ACSS Technical Newsletter 8008359, Revision A, 
dated January 12, 2011, as installed on but not limited to various 
transport and small airplanes, certificated in any category. That NPRM 
was published in the Federal Register on December 28, 2010 (75 FR 
81512). That NPRM proposed to require upgrading software.
    That NPRM was prompted by reports of anomalies with TCAS units 
during a flight test over high density airports (Chicago, New York, and 
Atlanta). The TCAS units dropped several reduced surveillance aircraft 
tracks because of interference limiting. This action revises that NPRM 
by proposing to require new updated software for certain TCAS units. We 
are proposing this supplemental NPRM to correct the unsafe condition on 
some of these products (the TCAS II, TCAS 2000, and T2CAS) that have an 
issue on some installations on which the TCAS unit reverts to the 
standby (STBY) mode (TCAS OFF) when the active transponder senses an 
altitude mis-compare between two Gilham altitude input or other 
possible air data source failure. This potential safety issue is 
dependent on the altitude interface to the transponder and the 
transponder used.

Actions Since Previous NPRM Was Issued

    Since we issued the previous NPRM, we have determined that certain 
software referenced in the original NPRM may not adequately address the 
unsafe condition for certain affected airplanes. ACSS has revised the 
associated service bulletins, as described below under ``Request to 
Delay AD Pending TCAS Validation.'' We are issuing this supplemental 
NPRM to propose installing the new upgraded software via the revised 
versions of these service bulletins. The revised service bulletins 
provide instructions on how to accomplish the software upgrade; the 
specific software approvals, however, are still pending and are 
expected to be complete before the final rule is issued.

Comments

    We gave the public the opportunity to comment on the previous NPRM. 
The following presents the comments received on the NPRM and the FAA's 
response to each comment.

Support for NPRM

    Boeing concurred with the contents of the original NPRM.

Requests To Withdraw NPRM

    ACSS disagreed with certain information in the Discussion section 
of the original NPRM.
    The Discussion section stated that anomalies with ACSS TCAS units 
``occurred during a flight test over a high density airport.'' ACSS 
stated that it provided the initial report of the anomaly to the FAA in 
late 2009, and that the FAA reproduced that scenario during another 
flight test in early 2010. ACSS noted, however, that in over 35 million 
flight hours of ACSS TCAS systems in field operation, no operator has 
ever reported to ACSS any such anomaly being observed. Moreover, ACSS 
is not aware of any such reports having been provided to the FAA. ACSS 
concludes that the probability of such an event is low enough that an 
AD to address the potential situation is unnecessary.
    The Discussion section of the original NPRM also stated that 
dropped tracks by the TCAS units could lead to ``possible loss of 
separation of air traffic and possible mid-air collision.'' ACSS noted 
that the calculated probability associated with such a possible event 
is very low. To support this assertion, ACSS referred to Section 2.3 of 
ACSS Continuing Operational Safety Probability Assessment of the 
Interference Limiting Function, Document 8008352-001, Revision C, dated 
January 6, 2011. ACSS reported that it has never received any report of 
such an operational anomaly from field operation. ACSS added that this 
analysis would indicate that the probability of such an event is low 
enough that an AD to address the potential situation is unnecessary.
    We infer that the commenter is requesting that we withdraw the 
NPRM. We disagree. While the commenter claims that the probability is 
low, information gathered from several flight tests at different 
regional airports, analysis of flight and other testing data, and 
various meetings and discussions among various FAA offices, ACSS, and 
an FAA TCAS contractor indicate that the risk from the identified 
condition is unacceptable, and it is necessary to proceed with this 
action.

Request To Delay AD Pending TCAS Validation

    Dassault Aviation (Dassault) stated that the technical standard 
order (TSO)

[[Page 62323]]

for TCAS 2000, new part number (P/N) 7517900-55001 (referenced in 
corresponding ACSS Service Bulletin 8008229-001 (ATA Service Bulletin 
7517900-34-6040), Revision 01, dated September 30, 2010), has been 
approved, but the TSO for TCAS 3000, new P/N 9003000-55004 
(corresponding ACSS Service Bulletin 8008235-001 (ATA Service Bulletin 
9003000-34-6006), Revision 02, dated February 3, 2011), was scheduled 
to be approved in June 2011. Dassault reports that, as an airplane 
manufacturer and system integrator, it must certify those TCAS units 
against airworthiness requirements and ensure that modified units still 
operate properly within their target system environment. Dassault 
proposed that we wait to issue the final rule until the new TCAS units 
can be validated within their hosting avionics environment.
    We agree, for the reasons provided by the commenter. We have 
reviewed the following revised service bulletins:
     ACSS Service Bulletin 8008221-001 (ATA Service Bulletin 
9003500-34-6014), Revision 01, dated February 4, 2011.
     ACSS Service Bulletin 8008222-001 (ATA Service Bulletin 
9003500-34-6015), Revision 01, dated February 4, 2011.
     ACSS Service Bulletin 8008223-001 (ATA Service Bulletin 
9003500-34-6016), Revision 01, dated February 4, 2011.
     ACSS Service Bulletin 8008229-001 (ATA Service Bulletin 
7517900-34-6040), Revision 02, dated June 28, 2011.
     ACSS Service Bulletin 8008230-001 (ATA Service Bulletin 
4066010-34-6036), Revision 02, dated June 28, 2011.
     ACSS Service Bulletin 8008231-001 (ATA Service Bulletin 
7517900-34-6041), Revision 02, dated June 28, 2011.
     ACSS Service Bulletin 8008233-001 (ATA Service Bulletin 
9000000-34-6016), Revision 03, dated June 30, 2011.
     ACSS Service Bulletin 8008234-001 (ATA Service Bulletin 
9000000-34-6017), Revision 02, dated June 30, 2011.
     ACSS Service Bulletin 8008235-001 (ATA Service Bulletin 
9003000-34-6006), Revision 02, dated February 3, 2011.
     ACSS Service Bulletin 8008236-001 (ATA Service Bulletin 
7517900-34-6042), Revision 03, dated June 30, 2011.
     ACSS Service Bulletin 8008238-001 (ATA Service Bulletin 
9000000-34-6018), Revision 02, dated June 30, 2011.

These revisions provide procedures for installing new updated software. 
We have revised this supplemental NPRM to refer to the most recent 
service information, and provided credit for actions done before the 
effective date of the AD using previous service information as 
acceptable for compliance with the AD requirements.

Request To Clarify Applicability

    Several commenters reported difficulty determining the 
applicability of the original NPRM.
    David Schober stated that the applicability of the original NPRM is 
defined in service bulletins that are not available to the general 
public, so some readers might not be able to determine which airplanes 
or components are affected. Mr. Schober added that a mechanic or repair 
station that does not have access to the service bulletins could return 
a noncompliant airplane to service.
    The European Aviation Safety Agency (EASA) requested that we revise 
the original NPRM to specify the affected part numbers or software 
version.
    ACSS noted that the applicability of the original NPRM did not 
identify specific TCAS part numbers associated with the referenced 
service bulletins. ACSS accordingly issued ACSS Technical Newsletter 
8008359, which cross-references the service bulletins and specific TCAS 
part numbers. ACSS recommended that we revise the original NPRM to 
refer to this document.
    We agree with the request. This supplemental NPRM includes the 
information in table 1 of ACSS Technical Newsletter 8008359, Revision 
A, dated January 12, 2011, which provides additional information about 
affected TCAS part numbers. Following paragraph (c) of this 
supplemental NPRM, we have added new Note 1, which introduces new table 
1 to list the service information and the corresponding affected parts.

Request To Explain Effect of Revised Service Information on 
Applicability

    Mr. Schober expressed concern for the potential effect on the 
applicability if the referenced service information is revised. Mr. 
Schober asserted that revising the service information to include 
additional units not considered at this time would bypass the public 
comment required by the Administrative Procedure Act (APA) (Pub. L. 79-
404, 5 U.S.C. 551, et seq.).
    We agree to clarify the applicability of this supplemental NPRM. 
Where an AD refers to a service document for airplanes or components in 
the applicability, that service bulletin is specifically identified by 
its revision level. Only that revision level may be used to determine 
the applicability of the AD. Therefore, since the applicability of the 
AD cannot change in the future except by revising or superseding the 
AD, this supplemental NPRM does not violate the APA. We have not 
changed the supplemental NPRM regarding this issue.

Request To Provide Additional Information

    ACSS asserts that the information provided under the Summary and 
Discussion sections in the original NPRM provides very limited detail 
regarding the interference limiting issue. To help operators fully 
understand and assess the operational aspects of the interference 
limiting issue, ACSS recommended that we provide ACSS Technical 
Newsletter 8008359, ``Change 7 Interference Limiting Airworthiness 
Directive FAQs,'' Revision A, dated January 12, 2011.
    We agree. As explained previously, we have changed paragraph (c) in 
this supplemental NPRM to refer to this technical newsletter, which 
will be submitted to the Office of the Federal Register for approval of 
incorporation by reference in the final rule AD.

Request To Delay AD Issuance

    Empire Airlines (Empire) reported it could not respond to the 
original NPRM because the necessary information was not available and 
the proposed modification had not been submitted for TSO approval yet. 
Empire suggested that we issue the NPRM when more information is 
available.
    We disagree with the request. As noted previously in ``Actions 
Since Previous NPRM was Issued,'' ACSS is upgrading the software of 
each TCAS model and submitting it one at a time to the FAA for review 
and approval. We anticipate that all necessary software will be FAA 
approved and released before we issue the final rule. In proposing the 
compliance time of 48 months in the NPRM, we anticipated that the 
software would be released within the first year after the final rule 
was issued. Therefore, the compliance time proposed in the NPRM has 
been reduced from 48 months to 36 months in this supplemental NPRM.

Request To Consider Effect of TCAS Certification

    Dassault showed concern about the detrimental effect the original 
NPRM will have on the airplane delivery process for aircraft 
manufacturers around the world. Dassault reported that on the 
production line many airplanes equipped with the old TCAS part numbers 
are awaiting completion and final delivery. As a result, Dassault will 
be unable to issue a statement of

[[Page 62324]]

conformity (per FAA Order 8130.2G, Airworthiness Certification of 
Aircraft and Related Products, dated August 31, 2010) or a certificate 
of airworthiness (per EASA regulations) on these airplanes. Dassault 
requested relief in the form of two options: (1) Delaying issuance of 
the final rule for 12 months until ACSS can upgrade affected TCAS units 
currently installed so that Dassault can certify the interference 
limiting change and retrofit the equipment, or (2) excluding TCAS 3000 
old part numbers currently on Dassault Falcon Jet and Dassault Aviation 
completion/production lines that are waiting entry into service so 
that, once in the field, the equipment would be in compliance with the 
AD.
    We disagree that further revision of this supplemental NPRM is 
necessary. As stated previously, we anticipate that all necessary 
software will be approved and released before we issue the final rule. 
Therefore, Dassault will be able to install the required software in 
each airplane delivered after this AD's effective date and issue 
statements of conformity for those airplanes.

Request To Clarify Effect of the Supplemental Type Certificate (STC) on 
Applicability

    Mr. Schober stated that many affected TCAS units use an STC as the 
approved data, and most of those STCs identify equipment eligible for 
installation by part number. The commenter asserted that the referenced 
service information rolls the part numbers of the units, so those units 
would no longer be eligible for installation via the original STC.
    We agree to provide clarification. As indicated previously, we have 
added new table 1 in this supplemental NPRM to match each affected part 
number to its corresponding service document.

Request To Correct Statement of Unsafe Condition

    ACSS noted an inaccuracy in the following text from the NPRM 
Summary section:

    The TCAS units dropped several reduced surveillance aircraft 
tracks because of interference limiting. We are proposing this AD to 
prevent TCAS units from dropping tracks, which could compromise 
separation of air traffic and lead to subsequent mid-air collisions.

ACSS stated that the IL function--even the changed implementation 
approved by the FAA and proposed by the NPRM--will still result in 
dropped tracks, because that is the purpose of the IL function. ACSS 
agreed with the Relevant Service Information section of the NPRM, which 
stated that the change simply ``improves tracking.'' The commenter 
therefore suggested that we revise the NPRM to state that the AD will 
``minimize'' rather than prevent dropped tracks.
    We disagree. The current ACSS implementation of TCAS is susceptible 
to dropping surveillance aircraft tracks because of interference 
limiting. This supplemental NPRM would require revising the current 
TCAS software to prevent dropping of TA and potential RA tracking cause 
by interference limiting.We have not changed this supplemental NPRM 
regarding this issue. The supplemental NPRM also corrects the altitude 
source issue in some of the ACSS TCAS product installations.

Request for Information on the Incident

    J. Twombly asked whether the ACSS anomaly that prompted the NPRM 
had any effect on the operation of the aircraft's transponder, or 
whether the transponder continued to operate in a normal manner, 
broadcasting and responding to interrogations, notwithstanding the ACSS 
anomaly. The commenter further questioned whether the transponder 
performance was verified during the investigation.
    The Mode S transponder of the airplane was verified to be 
performing in normal status operation during the flight test, despite 
the TCAS operational issue of the interference limiting anomaly. This 
anomaly in TCAS has no effect on Mode S transponder operation. We have 
made no change to this supplemental NPRM in this regard.

Request To Revise FAA's Determination

    ACSS requested that we revise the following sentence from the 
``FAA's Determination and Requirements of This Proposed AD'' section of 
the original NPRM:

    We are proposing this AD because we evaluated all relevant 
information and determined the unsafe condition described previously 
is likely to exist or develop in other products of these same type 
designs.

ACSS clarified that the operation of the IL function in question was 
not the result of an error in implementation. The IL function was 
specifically implemented to operate as it does in order to comply with 
the requirements of the TSO MOPS for Change 7 (i.e., TSO-C119b), as 
ACSS interpreted those requirements. As such, ACSS considered the NPRM 
misleading in its statement that the unsafe condition was likely to 
exist or develop in ``other products of these same type designs.'' ACSS 
had already implemented the FAA-directed change in all current and 
future versions (e.g., TSO-C119c; Change 7.1-compliant systems). ACSS 
recommended that we revise the statement to indicate that the unsafe 
condition ``exists in various ACSS TCAS systems.''
    We disagree with the request. We have determined that the 
identified unsafe condition exists in the affected TCAS products, and 
might develop in products with the same type design, unless the actions 
proposed in this supplemental NPRM are done. We have not changed the 
supplemental NPRM regarding this issue.

Request To Revise Certain Assertions Made in Original NPRM

    ACSS questioned the accuracy of the following statement from the 
Discussion section of the NPRM: ``When the TCAS unit interrogated 
aircraft in a high density airport area, some of the targets 
disappeared from the cockpit display or were not recognized.'' ACSS 
asserted that this claim is incorrect, and added that the TCAS system 
continues to monitor the airspace and receive Mode S squitter 
information from all aircraft within detection range, even when the 
interrogation power is being limited by the IL function. ACSS therefore 
suggested that we revise the statement to remove the words ``or were 
not recognized.''
    Although the Discussion section from an NPRM is not repeated in a 
supplemental NPRM, we agree to provide clarification. The statement 
quoted by the commenter appears to be taken out of context from a more 
complete document. As long as information is within detection range and 
is being processed, MODE S recognition exists. But when tracking power 
is not available as a result of IL, not only will tracks disappear from 
the display, those targets will not be tracked because the lack of 
power does not permit maintenance of tracks. Therefore the tracks are 
dropped and will not be recognized and may result in loss of separation 
of own aircraft with other target aircraft. We have not changed the 
supplemental NPRM regarding this issue.

Request To Revise Proposed Cost Estimate

    Mr. Schober noted that the Costs of Compliance section of the 
original NPRM considered only the actual updating of the unit--not the 
time to remove the unit, package and ship the unit to a repair station, 
return the unit to the aircraft owner, and re-install the unit, or the 
down time for the airplane for this maintenance evolution and the 
associated lost revenue.
    Empire asserted that it would be necessary to read each ACSS 
service

[[Page 62325]]

document listed in the original NPRM to determine the applicability, 
and wondered whether we included this research time in our calculations 
for determining the financial impact of the original NPRM.
    We infer that the commenters want us to revise the estimated costs 
to account for those variables. We disagree. The cost information in 
this supplemental NPRM describes only the direct costs of the specific 
required actions. Based on the best data available, the manufacturer 
provided the number of work-hours necessary to do the proposed actions. 
This number represents the time necessary to perform only the actions 
actually proposed by this supplemental NPRM. We recognize that, in 
doing actions required by an AD, operators might incur incidental costs 
in addition to the direct costs. But the cost analysis in AD rulemaking 
actions typically does not include incidental costs such as the time 
necessary for planning, airplane down time, or time necessitated by 
other administrative actions. Those incidental costs, which might vary 
significantly among operators, are almost impossible to calculate. We 
have not changed the supplemental NPRM regarding this issue.

FAA's Determination

    We are proposing this supplemental NPRM because we evaluated all 
the relevant information and determined the unsafe condition described 
previously is likely to exist in other products of these same type 
designs. Certain changes described above expand the scope of the 
original NPRM. As a result, we have determined that it is necessary to 
reopen the comment period to provide additional opportunity for the 
public to comment on this supplemental NPRM.

Proposed Requirements of the Supplemental NPRM

    This supplemental NPRM would require upgrading software.

Costs of Compliance

    We estimate that this proposed AD affects 9,000 airplanes of U.S. 
registry. We estimate the following costs to comply with this proposed 
AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                    Cost per       Cost on U.S.
               Action                        Labor cost           Parts cost        product         operators
----------------------------------------------------------------------------------------------------------------
Software upgrade....................  2 work-hours x $85 per           $2,870           $3,040      $27,360,000
                                       hour = $170.
----------------------------------------------------------------------------------------------------------------

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 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 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),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) 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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive (AD):

Aviation Communication & Surveillance Systems, LLC: Docket No. FAA-
2010-1204; Directorate Identifier 2010-NM-147-AD.

(a) Comments Due Date

    We must receive comments by November 7, 2011.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Aviation Communication & Surveillance Systems 
(ACSS) traffic alert and collision avoidance system (TCAS) units 
with part numbers identified in ACSS Technical Newsletter 8008359, 
as installed on but not limited to various transport and small 
airplanes, certificated in any category.

    Note 1:  Table 1 of this AD also provides a cross-referenced 
list of part numbers with associated service bulletins to help 
operators identify affected parts.

                                Table 1--Service Bulletin and LRU Cross-Reference
----------------------------------------------------------------------------------------------------------------
                                                        Affected LRU part Nos. (P/
                    ACCS product--                                 Ns)--               ACSS Service Bulletin--
----------------------------------------------------------------------------------------------------------------
TCAS 3000SP..........................................  9003500-10900, -10901, -      8008221-001, Revision 01,
                                                        10902, -55900, -55901, -      dated February 4, 2011
                                                        55902, -57901, -65900, -      (ATA Service Bulletin
                                                        65901, -65902.                9003500-34-6014).

[[Page 62326]]

 
TCAS 3000SP..........................................  9003500-10001, -10002, -      8008222-001, Revision 01,
                                                        10003, -10004, -55001, -      dated February 4, 2011
                                                        55002, -55003, -55004, -      (ATA Service Bulletin
                                                        65001, -65002, -65003, -      9003500-34-6015).
                                                        65004.
TCAS 3000SP..........................................  9003500-10802...............  8008223-001, Revision 01,
                                                                                      dated February 4, 2011
                                                                                      (ATA Service Bulletin
                                                                                      9003500-34-6016.
TCAS 2000............................................  7517900-10003, -10004, -      8008229-001, Revision 02,
                                                        10006, -10007, -10011, -      dated June 28, 2011 (ATA
                                                        55003, -55004, -55006, -      Service Bulletin 7517900-
                                                        55007, -55009, -55011, -      34-6040).
                                                        71003, -71004, -71006, -
                                                        71007, -71011.
TCAS II..............................................  4066010-910, -912...........  8008230-001, Revision 02,
                                                                                      dated June 28, 2011 (ATA
                                                                                      Service Bulletin 4066010-
                                                                                      34-6036).
Military TCAS 2000...................................  7517900-56101, -56102, -      8008231-001, Revision 02,
                                                        56104, -56105, 56107.         dated June 28, 2011 (ATA
                                                                                      Service Bulletin 7517900-
                                                                                      34-6041).
T2CAS................................................  9000000-10002, -10003, -      8008233-001, Revision 03,
                                                        10004, -10005, -10006, -      dated June 30, 2011 (ATA
                                                        10008, -10204, -10205, -      Service Bulletin 9000000-
                                                        10206, -10208, -20002, -      34-6016).
                                                        20003, -20004, -20005, -
                                                        20006, -20008, -20204, -
                                                        20205, -20206, -20208, -
                                                        55002, -55003, -55004, -
                                                        55005, -55006, -55008, -
                                                        55204, -55205, -55206, -
                                                        55208.
T2CAS................................................  9000000-10110, -11111.......  8008234-001, Revision 02,
                                                                                      dated June 30, 2011 (ATA
                                                                                      Service Bulletin 9000000-
                                                                                      34-6017).
TCAS 3000............................................  9003000-10001, -10002, -      8008235-001, Revision 02,
                                                        10003, -55001, -55002, -      dated February 3, 2011
                                                        55003, -65001, -65002, -      (ATA Service Bulletin
                                                        65003.                        9003000-34-6006).
Military TCAS 2000 MASS..............................  7517900-20001, -20002, -      8008236-001, Revision 03,
                                                        65001, -65002.                dated June 30, 2011 (ATA
                                                                                      Service Bulletin 7517900-
                                                                                      34-6042).
Military T2CAS MASS..................................  9000000-30006, -40006, -      8008238-001, Revision 02,
                                                        60006.                        dated June 30, 2011 (ATA
                                                                                      Service Bulletin 9000000-
                                                                                      34-6018).
----------------------------------------------------------------------------------------------------------------

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 34, Navigation.

(e) Unsafe Condition

    This AD was prompted by reports of anomalies with TCAS units 
during a flight test over a high density airport. The TCAS units 
dropped several reduced surveillance aircraft tracks because of 
interference limiting. We are issuing this AD to prevent TCAS units 
from dropping tracks, which could compromise separation of air 
traffic and lead to subsequent mid-air collisions.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Upgrade Software

    Within 36 months after the effective date of this AD, upgrade 
software for the ACSS TCAS, in accordance with the Accomplishment 
Instructions of the applicable ACSS publication identified in table 
1 of this AD.

    Note 2:  ACSS Service Bulletin 8008233-001 (ATA Service Bulletin 
9000000-34-6016), Revision 03, dated June 30, 2011, contains three 
part numbers (P/Ns 9000000-10007, -20007, and -55007) that were 
never produced.

(h) Actions Done in Accordance With Previous Service Information

    A software upgrade done before the effective date of this AD in 
accordance with the applicable service bulletin identified in 
paragraphs (h)(1) through (h)(13) of this AD is acceptable for 
compliance with the requirements of paragraph (g) of this AD.
    (1) ACSS Service Bulletin 8008221-001 (ATA Service Bulletin 
9003500-34-6014), dated May 27, 2010.
    (2) ACSS Service Bulletin 8008222-001 (ATA Service Bulletin 
9003500-34-6015), dated May 27, 2010.
    (3) ACSS Service Bulletin 8008223-001 (ATA Service Bulletin 
9003500-34-6016), dated May 27, 2010.
    (4) ACSS Service Bulletin 8008229-001 (ATA Service Bulletin 
7517900-34-6040), Revision 01, dated September 30, 2010.
    (5) ACSS Service Bulletin 8008230-001 (ATA Service Bulletin 
4066010-34-6036), Revision 01, dated February 1, 2011.
    (6) ACSS Service Bulletin 8008231-001 (ATA Service Bulletin 
7517900-34-6041), Revision 01, dated October 15, 2010.
    (7) ACSS Service Bulletin 8008233-001 (ATA Service Bulletin 
9000000-34-6016), Revision 02, dated February 1, 2011.
    (8) ACSS Service Bulletin 8008234-001 (ATA Service Bulletin 
9000000-34-6017), Revision 01, dated February 1, 2011.
    (9) ACSS Service Bulletin 8008235-001 (ATA Service Bulletin 
9003000-34-6006), dated June 4, 2010.
    (10) ACSS Service Bulletin 8008236-001 (ATA Service Bulletin 
7517900-34-6042), dated May 27, 2010.
    (11) ACSS Service Bulletin 8008236-001 (ATA Service Bulletin 
7517900-34-6042), Revision 02, dated February 1, 2011.
    (12) ACSS Service Bulletin 8008238-001 (ATA Service Bulletin 
9000000-34-6018), dated June 4, 2010.
    (13) ACSS Service Bulletin 8008238-001 (ATA Service Bulletin 
9000000-34-6018), Revision 01, dated February 1, 2011.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles Aircraft Certification Office 
(ACO), FAA, has the authority to approve AMOCs for this AD, if 
requested using the procedures found in 14 CFR 39.19. In accordance 
with 14 CFR 39.19, send your request to your principal inspector or 
local Flight Standards District Office, as appropriate. If sending 
information directly to the manager of the ACO, send it to the 
attention of the person identified in the Related Information 
section of this AD.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(j) Related Information

    (1) For more information about this AD, contact Abby Malmir, 
Aerospace Engineer, Systems and Equipment Branch, ANM-130L, FAA, Los 
Angeles ACO, 3960 Paramount Boulevard, Lakewood, California 90712-
4137; phone: 562-627-5351; fax: 562-627-5210; e-mail: 
abby.malmir@faa.gov.
    (2) For service information identified in this AD, contact 
Aviation Communication & Surveillance Systems, LLC, 19810 North 7th 
Avenue, Phoenix, Arizona 85027-4741; phone: 623-445-7040; fax: 623-
445-7004; e-mail: 3com.com">acss.orderadmin@L-3com.com; Internet: http://www.acss.com. You may review copies of the referenced service 
information at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington. For information on the availability 
of this material at the FAA, call 425-227-1221.

[[Page 62327]]

    Issued in Renton, Washington, on September 29, 2011.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.

[FR Doc. 2011-26084 Filed 10-6-11; 8:45 am]
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