Discussion
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain Trig Avionics Limited TT31, Avidyne Corporation AXP340, and BendixKing/Honeywell International KT74 Mode S transponders. The NPRM published in the Federal Register on March 22, 2019 (84 FR 10735). The NPRM was prompted by the discovery that the retaining cam that engages in the mounting tray may not withstand g-forces experienced during an emergency landing. The NPRM proposed to require one-time inspection of the transponder installation to determine if it is a conventional aft- facing installation, and depending on the findings, removal of the affected transponder for modification. The FAA is issuing this AD to address the unsafe condition on these products.
The European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued EASA AD 2018-0247,dated November 13, 2018 (referred to after this as ``the MCAI''), to address the unsafe condition on these products. The MCAI states:
While testing a new model of transponder, it was detected that the retaining cam was not meeting the approved design criteria for crash safety shock in the aft direction (20g sustained). This was due to an uncontrolled deviation in the manufacturing process of the retaining cam by the part manufacturer. The retaining cam is a small nylon part that engages in the mounting tray when the transponder is installed into the aircraft. Additional tests using affected retaining cam showed that the transponders meet RTCA/DO-106G Section 7.0 operational shocks and crash safety impulse tests, as well as RTCA/DO-160G Section 7.0 crash safety sustained tests for all directions, except the aft direction. As a consequence, units which have been installed with a control panel orientation that is not opposite to the direction of flight may not withstand g-forces experienced during an emergency landing. This condition, if not detected and corrected, could lead to detachment of the transponder, possibly resulting in damage to fuel systems or emergency evacuation equipment, and/or injury to aircraft occupants.
To address this potential unsafe condition, Trig Avionics published the applicable SB to provide instructions to inspect the installation and the transponder, and how to arrange for modification.
For the reason described above, this [EASA] AD requires a one- time inspection of the transponder installation to determine whether this is a conventional installation, as defined in this [EASA] AD, and, depending on findings, removal from service of the affected transponder for modification.
You may obtain further information by examining the MCAI in the AD docket on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2018-1081.
Comments
The FAA gave the public the opportunity to participate in developing this final rule. The following presents the comments received on the NPRM and the FAA's response to each comment.
Request To Clarify Compliance
An individual commenter commented that paragraph (g)(1) of the NPRM does not state clearly that no further action is required if the transponder is installed in a conventional rear facing installation.
The FAA agrees. The FAA added a new paragraph (g)(2) to this AD to indicate that no further action is required if the transponder is installed
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in a conventional aft-facing avionics rack. Because of this change, paragraph (g)(2) in the NPRM becomes paragraph (g)(3) and paragraph (g)(3) in the NPRM becomes paragraph (g)(4) in this AD.
Support for the AD
An individual commenter supported the AD because it is cost- effective and the manufacturer may cover some of the costs under warranty.
Conclusion
The FAA reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this final rule with the change described previously and minor editorial changes. The FAA has determined that these minor changes:
[Agr]re consistent with the intent that was proposed in the NPRM for addressing the unsafe condition; and
Do not add any additional burden upon the public than was already proposed in the NPRM.
The FAA has also determined that these changes will not increase the economic burden on any operator or increase the scope of this final rule.
Related Service Information Under 1 CFR Part 51
The FAA reviewed Trig Avionics Limited Service Bulletin (SB) SUP/ TT31/027, Issue 1.0, dated October 1, 2018; Trig Avionics Limited SB SUP/AXP340/002, Issue 1.0, dated October 1, 2018; and Trig Avionics Limited SB SUP/KT74/005, Issue 1.0, dated October 1, 2018.
Trig Avionics Limited SB SUP/TT31/027, Issue 1.0, dated October 1, 2018, describes procedures for determining the direction of the TrigAvionics Limited TT31 Mode S transponder installation and removal of these affected transponders for replacement or repair. Trig Avionics Limited SB SUP/AXP340/002, Issue 1.0, dated October 1, 2018, describes procedures for determining the direction of the Avidyne Corporation AXP340 Mode S transponder installation and removal of these affected transponders for replacement or repair. Trig Avionics Limited SB SUP/ KT74/005, Issue 1.0, dated October 1, 2018, describes procedures for determining the direction of the BendixKing/Honeywell International KT74 Mode S transponder installation and removal of these affected transponders for replacement or repair.
This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.
Costs of Compliance
The FAA estimates that this AD affects 2,390 transponders 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 ---------------------------------------------------------------------------------------------------------------- Inspect the transponder installation 0.5 work-hours x $85 $0 $42.50 $101,575
per hour = $42.50. ----------------------------------------------------------------------------------------------------------------
The FAA estimates the following costs to do any necessary repairs that are required based on the results of the inspection. The FAA has no way of determining the number of aircraft that might need these repairs:
On-Condition Costs ----------------------------------------------------------------------------------------------------------------
Cost per
Action Labor cost Parts cost product ---------------------------------------------------------------------------------------------------------------- Replace the transponder...................... 1 work-hour x $85 per hour = $2,872 $2,957
$85. ----------------------------------------------------------------------------------------------------------------
According to the manufacturer, some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected individuals. The FAA does not control warranty coverage for affected individuals. As a result, the FAA has included all costs in our cost estimate.
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.
This AD is issued in accordance with authority delegated by the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to engines, propellers, and associated appliances to the Manager, Engine and Propeller Standards Branch, Policy and Innovation Division.
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 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
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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.