Document ID: FAA-2020-0991-0010
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Garmin International GMN-00962 GTS Processor Units
Posted Date: 2021-04-12T04:00Z

[Federal Register Volume 86, Number 68 (Monday, April 12, 2021)]
[Rules and Regulations]
[Pages 18887-18890]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-07422]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0991; Project Identifier AD-2020-00478-Q; 
Amendment 39-21509; AD 2021-08-15]
RIN 2120-AA64

Airworthiness Directives; Garmin International GMN-00962 GTS 
Processor Units

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Garmin International (Garmin) GMN-00962 GTS processor units 
(GTS 825, GTS 855, GTS 8000). This AD was prompted by reports of GTS 
processor units issuing resolution advisories (RAs) when no risk of 
collision or loss of separation exists between the airplanes involved. 
This AD requires updating the software version of the affected GTS 
Processor units. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective May 17, 2021.

ADDRESSES: For service information identified in this final rule, 
contact Garmin International, Garmin Aviation Support 1200 E. 151st 
Street, Olathe, KS 66062; phone: (866) 739-5687; website: https://fly.garmin.com/fly-garmin/support/. You may view this service 
information at the FAA, Airworthiness Products Section, Operational 
Safety Branch, 901 Locust St., Kansas City, MO 64106. For information 
on the availability of this material at the FAA, call (816) 329-4148.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2020-0991; or in person at 
Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The AD docket contains this final rule, any 
comments received, and other information. The address for Docket 
Operations is U.S. Department of Transportation, Docket Operations, M-
30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue 
SE, Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Paul Rau, Aviation Safety Engineer, 
Wichita ACO Branch, FAA, 1801 Airport Road, Wichita, KS 67209; phone: 
(316) 946-4149; fax: (316) 946-4107; email: paul.rau@faa.gov or 
Wichita-COS@faa.gov.

SUPPLEMENTARY INFORMATION: 

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to Garmin GMN-00962 GTS 
processor units (GTS 825, GTS 855, GTS 8000) with part number 011-
02571-0( ) and software version 3.13 or earlier (except version 
3.12.1). The NPRM published in the Federal Register on December 14, 
2020 (85 FR 80696). The NPRM was prompted by seven reports of false RAs 
involving aircraft equipped with Garmin GMN-00962 GTS processor 
configured for traffic collision avoidance system II (TCAS II)

[[Page 18888]]

(configuration marketed as GTS-8000 units). The Garmin GMN-00962 GTS 
processor units are marketed by Garmin as the GTS 825, GTS 855 or GTS 
8000, with the marketing name representing the traffic system 
configuration.
    A false RA occurs when there is no risk of collision or loss of 
separation of the airplanes. These false RAs result from the GTS 
Processor software potentially calculating incorrect range rates. This 
results in traffic advisories or RAs being generated when targets are 
greater than 10 nautical miles (NM) away. A TCAS event involving three 
or more airplanes can result in mid-air collision by increasing the 
risk that the TCAS, in resolving the false RA with the initial 
airplane, will create an actual loss of separation with a third 
airplane. This condition, if not addressed, could result in an RA being 
generated when no risk of loss of separation or risk of collision 
exists between the airplanes involved, which can lead to a mid-air 
collision with a third airplane.
    In the NPRM, the FAA proposed to require updating the GTS processor 
unit software. The FAA is issuing this AD to address the unsafe 
condition on these products.
    The affected GTS processor units were installed on the airplanes 
listed below during production and via an STC; however, the affected 
units may have been installed on other airplane models as a 
supplemental type certificate (STC). Although the names found in 
parenthesis may not be listed on the type certificate, the manufacturer 
may use those names as marketing names for the airplanes.
     Textron Aviation Inc. (type certificate previously held by 
Cessna Aircraft Company) Model 525 (Cessna Citation M2), Model 525B 
(Cessna Citation CJ3+), Model Model 680 Sovereign, Model 680A Latitude, 
and Model 700 (Cessna Citation Longitude);
     Embraer S.A. Model EMB-500 (Phenom 100) and Model EMB-505 
(Phenom 300);
     Learjet Inc. Model 45 (Learjet 70) and Model 45 (Learjet 
75); and
     Viking Air Limited (type certificate previously held by 
Shorts Brothers PLC, Shorts Brothers Limited) Model SD3-60 SHERPA, 
modified by Field Aerospace STC No. ST00865DE.

Discussion of Final Airworthiness Directive Comments

    The FAA received comments from six commenters. The commenters were 
Garmin, Learjet Inc. (Learjet), Textron Aviation Inc. (Textron), 
NetJets, Field Aerospace, and an individual. The following presents the 
comments received on the NPRM and the FAA's response to each comment.

Supportive

    An individual commenter supported the NPRM without change.

Request Regarding Applicability

    Garmin requested the FAA clarify the AD applicability, as the 
proposed AD applies to GTS 825 and GTS 855, which are not affected by 
the false RA issue. Garmin suggested that the FAA add a clarifying 
statement to the background section, and revise the applicability 
paragraph to remove references to the GTS 825 and GTS 855.
    The FAA disagrees. This AD applies to the GTS Processor part number 
011-02571-0( ) units with software version 3.13 or earlier, except 
software version 3.12.1. The GTS 825, GTS 855, and GTS 8000 marketing 
labels describe different installation configurations rather than 
different appliances. While the GTS Processor will not generate false 
RAs when configured as TAS (GTS 825) or TCAS I (GTS 855), the appliance 
itself is still susceptible to the issue, and the unsafe condition 
would occur if an operator enables the TCAS II option without also 
updating the software.
    The FAA did not change this AD based on this comment.

Request Regarding Affected Aircraft

    Field Aerospace stated that the proposed AD would affect Shorts 
Sherpa Model SD3-60 airplanes that have been modified under Field 
Aerospace STC No. ST00865DE.
    The FAA agrees with this comment. The FAA issued this AD against 
the Garmin appliance because the unsafe condition exists in the 
appliance. The FAA has added Model SD3-60 SHERPA airplanes modified by 
Field Aerospace STC No. ST00865DE to the list of known affected 
aircraft in the background section. This is not an all-inclusive list; 
all operators must check their airplanes for the affected appliance, 
regardless of whether the model of their airplane is listed.

Request Regarding Unsafe Condition

    Garmin requested the FAA add information relevant to the actual 
risk in the discussion of the unsafe condition in the background 
section. Specifically, Garmin stated that loss of separation with a 
third airplane is not inevitable when a false RA occurs. Garmin further 
stated that the TCAS II implemented by the GTS 8000 is capable of 
negotiating threats with more than one airplane and will adjust the RA 
in a situation should loss of separation to a third airplane result in 
a collision threat.
    The FAA disagrees. The unsafe condition statement describes the 
condition the FAA is trying to prevent; as such, it does not describe 
all possible outcomes. The FAA assessed the likelihood of the unsafe 
condition in determining whether an AD or other action was warranted. 
While the FAA acknowledges that no loss of separation event has been 
associated with this issue on Garmin equipment, a similar issue with 
other TCAS II equipment has resulted in loss of separation events. 
Additionally, the rate of false RAs observed with GTS Processor-
equipped aircraft far exceeds the acceptable probability of a false RA 
due to a failure of the system specified in Advisory Circular No. 20-
151C, Airworthiness Approval of Traffic Alert and Collision Avoidance 
Systems (TCAS II), Versions 7.0 & 7.1 and Associated Mode S 
Transponders, dated July 21, 2017. Further, the potential for a loss of 
separation is not limited to the GTS Processor-equipped aircraft, as 
the second aircraft may also contain equipment that attempts to resolve 
the multi-threat encounter. Although the TCAS II is capable of 
resolving conflicts with more than one aircraft, since the current 
design of TCAS RAs is limited to vertical maneuvers, it is not able to 
provide conflict resolution for all encounters involving multiple 
aircraft.
    The FAA did not change this AD based on this comment.

Request Regarding Required Actions and Compliance

    Garmin requested the FAA revise the AD to require updating the 
affected software to version 3.12.1, or to version 3.14 or later. 
Garmin stated that, as proposed, the AD would not allow update of 
software to version 3.12.1, which is not affected by the issue.
    The FAA agrees with this comment. The unsafe condition is also 
resolved in version 3.12.1. The FAA has changed the Required Actions 
and Compliance paragraph to also allow updating the GTS processor 
software to version 3.12.1.
    Learjet, Textron, and NetJets requested the FAA extend the 
compliance time to allow adequate time for the certification and 
deployment of the required changes to all affected products. Learjet 
requested a compliance time of 18 months, while Textron requested a 
compliance time of 24 months.
    The FAA agrees. In addition to the reasons provided by the 
commenters, the FAA's risk assessment, in consideration of the ongoing 
pandemic and resulting reduction in air traffic,

[[Page 18889]]

supports extending the compliance time from 12 to 24 months.

Request Regarding Costs

    Textron requested the FAA update the estimated cost information to 
include additional work for Textron aircraft. Textron stated it has 
prior agreements with Garmin to accomplish this software change as part 
of a package of other product improvements, for a per-aircraft cost of 
approximately $3,000.
    The FAA disagrees with this comment. The cost analysis in AD 
rulemaking actions typically includes only the costs associated with 
complying with the AD. This AD does not mandate the entire package of 
changes for Textron aircraft.
    The FAA has not made changes to this AD based on this comment.

Request Regarding Certificate of Airworthiness

    Learjet requested the FAA revise the AD to allow initial 
Certificates of Airworthiness to be issued to newly-manufactured 
aircraft prior to complying with the AD. Learjet stated that 
certification of new software to comply with the AD (software later 
than version 3.13) will take a minimum of 9 months.
    The FAA disagrees with this comment. The AD does not prohibit the 
issuance of a Certificate of Airworthiness to eligible aircraft. Newly-
manufactured aircraft need to comply with the AD actions within the 
same timeframe as aircraft in the current U.S. fleet.
    The FAA has not made changes to this AD based on this comment.

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting this AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. Except for minor editorial changes and any 
other changes described previously, this AD is adopted as proposed in 
the NPRM. None of the changes will increase the economic burden on any 
operator.

Related Service Information

    The FAA reviewed Garmin Service Bulletin No. 2065, Revision A, 
dated May 7, 2020; and Garmin Service Bulletin No. 1948, Revision B, 
dated March 26, 2020. These service bulletins contain procedures for 
uploading the software update to the GMN-00962 GTS Processor units (GTS 
825, GTS 855, GTS 8000).

Costs of Compliance

    The FAA estimates that this AD affects 700 appliances installed on 
airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Update GTS Processor software.........  4.00 work-hours x $85                 $0            $340        $238,000
                                         per hour = $340.
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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.
    The FAA is 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

    This AD will not have federalism implications under Executive Order 
13132. This AD will 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 that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, 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.

List of Subjects in 14 CFR Part 39

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

The Amendment

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

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2021-08-15 Garmin International: Amendment 39-21509; Docket No. FAA-
2020-0991; Project Identifier AD-2020-00478-Q.

(a) Effective Date

    This airworthiness directive (AD) is effective May 17, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Garmin International GMN-00962 GTS processor 
units, part number 011-02571-0( ), with software version 3.13 or 
earlier, except software version 3.12.1, installed on airplanes 
certificated in any category. These units are marketed as the GTS 
825, GTS 855, or GTS 8000.

(d) Subject

    Joint Aircraft System Component (JASC) Code 3445, AIR COLLISION 
AVOIDANCE SYSTEM (TCAS).

(e) Unsafe Condition

    This AD was prompted by the GTS processor unit issuing false 
resolution advisories (RAs) when no risk of collision or loss of 
separation exists between the airplanes involved. A traffic 
collision avoidance system (TCAS) event involving

[[Page 18890]]

three or more airplanes can result in mid-air collision by 
increasing the risk that the TCAS, in resolving the false RA between 
the initial airplane, will create an actual loss of separation with 
a third airplane. The FAA is issuing this AD to prevent these false 
RAs, which can lead to a mid-air collision with a third airplane.

(f) Required Action and Compliance

    Within 24 months after the effective date of this AD, update the 
GTS processor software to a version that is not 3.13 or earlier, 
except 3.12.1. Software version 3.12.1 does not contain the unsafe 
condition.

(g) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Wichita ACO Branch, 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 certification office, send it to the attention of the 
person identified in Related Information.
    (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.

(h) Related Information

    (1) For more information about this AD, contact Paul Rau, 
Aviation Safety Engineer, Wichita ACO Branch, FAA, 1801 Airport 
Road, Wichita, KS 67209; phone: (316) 946-4149; fax: (316) 946-4107; 
email: paul.rau@faa.gov or 50073933383924317d131f03103631317e373f26.
    (2) For service information identified in this AD contact Garmin 
International, Garmin Aviation Support 1200 E. 151st Street, Olathe, 
KS 66062; phone: (866) 739-5687; website: https://fly.garmin.com/fly-garmin/support/. You may also view this service information at 
FAA, Airworthiness Products Section, Operational Safety Branch, 901 
Locust St., Kansas City, MO 64106. For information on the 
availability of this material at the FAA, call (816) 329-4148.

    Issued on April 7, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-07422 Filed 4-9-21; 8:45 am]
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