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Proposed Rule

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

Action

Supplemental Notice Of Proposed Rulemaking (Nprm); Reopening Of Comment Period.

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.

Unified Agenda

Airworthiness Directives

1 action from October 2014

  • October 2014
    • Actions Will Continue Through
 

Table of Contents Back to Top

Tables Back to Top

DATES: Back to Top

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

ADDRESSES: Back to Top

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, 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: 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 Back to Top

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: Back to Top

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: Back to Top

Comments Invited Back to Top

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 Back to Top

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 altitudemis-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 Back to Top

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 Back to Top

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 Back to Top

Boeing concurred with the contents of the original NPRM.

Requests To Withdraw NPRM Back to Top

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 Back to Top

Dassault Aviation (Dassault) stated that the technical standard order (TSO) 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 Back to Top

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 Back to Top

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) (79, 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 Back to Top

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 Back to Top

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 Back to Top

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 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 Back to Top

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 Back to Top

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 Back to Top

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 Back to Top

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 Back to Top

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 Back to Top

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 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 Back to Top

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 Back to Top

This supplemental NPRM would require upgrading software.

Costs of Compliance Back to Top

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

Authority for This Rulemaking Back to Top

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 Back to Top

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 Back to Top

The Proposed Amendment Back to Top

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

begin regulatory text

PART 39—AIRWORTHINESS DIRECTIVES Back to Top

1. The authority citation for part 39 continues to read as follows:

Authority:

49 U.S.C. 106(g), 40113, 44701.

§ 39.13 [Amended]

2. The FAA amends § 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 Back to Top

We must receive comments by November 7, 2011.

(b) Affected ADs Back to Top

None.

(c) Applicability Back to Top

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 Back to Top
ACCS product— Affected LRU part Nos. (P/Ns)— ACSS Service Bulletin—
TCAS 3000SP 9003500-10900, -10901, -10902, -55900, -55901, -55902, -57901, -65900, -65901, -65902 8008221-001, Revision 01, dated February 4, 2011 (ATA Service Bulletin 9003500-34-6014).
TCAS 3000SP 9003500-10001, -10002, -10003, -10004, -55001, -55002, -55003, -55004, -65001, -65002, -65003, -65004 8008222-001, Revision 01, dated February 4, 2011 (ATA Service Bulletin 9003500-34-6015).
TCAS 3000SP 9003500-10802 8008223-001, Revision 01, dated February 4, 2011 (ATA Service Bulletin 9003500-34-6016.
TCAS 2000 7517900-10003, -10004, -10006, -10007, -10011, -55003, -55004, -55006, -55007, -55009, -55011, -71003, -71004, -71006, -71007, -71011 8008229-001, Revision 02, dated June 28, 2011 (ATA Service Bulletin 7517900-34-6040).
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, -56104, -56105, 56107 8008231-001, Revision 02, dated June 28, 2011 (ATA Service Bulletin 7517900-34-6041).
T2CAS 9000000-10002, -10003, -10004, -10005, -10006, -10008, -10204, -10205, -10206, -10208, -20002, -20003, -20004, -20005, -20006, -20008, -20204, -20205, -20206, -20208, -55002, -55003, -55004, -55005, -55006, -55008, -55204, -55205, -55206, -55208 8008233-001, Revision 03, dated June 30, 2011 (ATA Service Bulletin 9000000-34-6016).
T2CAS 9000000-10110, -11111 8008234-001, Revision 02, dated June 30, 2011 (ATA Service Bulletin 9000000-34-6017).
TCAS 3000 9003000-10001, -10002, -10003, -55001, -55002, -55003, -65001, -65002, -65003 8008235-001, Revision 02, dated February 3, 2011 (ATA Service Bulletin 9003000-34-6006).
Military TCAS 2000 MASS 7517900-20001, -20002, -65001, -65002 8008236-001, Revision 03, dated June 30, 2011 (ATA Service Bulletin 7517900-34-6042).
Military T2CAS MASS 9000000-30006, -40006, -60006 8008238-001, Revision 02, dated June 30, 2011 (ATA Service Bulletin 9000000-34-6018).

(d) Subject Back to Top

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

(e) Unsafe Condition Back to Top

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 Back to Top

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

(g) Upgrade Software Back to Top

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 Back to Top

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) Back to Top

(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 Back to Top

(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: 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.

Issued in Renton, Washington, on September 29, 2011.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

end regulatory text

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

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