12698 Federal Register / Vol. 80, No. 46 / Tuesday, March 10, 2015 / Notices 

further increases the potential for 

inconsistent and unsatisfactory 

installations; 

(2) Hook and loop fasteners closed 

with proper tension may stretch or 

loosen over time due to wear, fluids, 

vibration, and repeated use, leading to 

insufficient tension to retain the ELT; 

(3) Hook and loop fasteners closed 

with proper tension do not provide 

stated retention capability due to debris 

which can contaminate the hooks and 

loops of the fastener; and 

(4) Hook and loop fasteners closed 

with proper tension degrade due to 

environmental factors such as repeated 

heating and cooling cycles, temperature 

extremes, and contamination resulting 

from location in equipment areas. 

FAA Actions 

After publishing our initial intent to 

withdraw the TSO Authorizations 

(TSOA) for TSO–C91a, and TSO–C126/ 

126a (See 135 FR 41,473 (2012)), the 

FAA considered five courses of action to 

mitigate safety concerns with the use of 

hook and loop fasteners to retain ELTs. 

These actions addressed design, 

production, and airworthiness 

approvals for both the TSO and retrofit 

for existing installations. Below is a 

summary of the actions and their 

outcomes: 

(1) Recommendation to revise 

Installation and Maintenance manuals. 

The FAA published a Safety Awareness 

Information Bulletin (SAIB) HQ–12–32, 

Hook and Loop Style Fasteners as a 

Mounting Mechanism for Emergency 

Locator Transmitters, on May 23, 2012. 

The SAIB outlined actions ELT 

manufacturers could take to improve 

their installation and maintenance 

instructions to mitigate the concerns 

with hook and loop retention. 

(2) Revised TSO–C126a for 406 MHz 

ELTs. The FAA published TSO–C126b, 

406 MHz Emergency Locator 

Transmitters, on November 26, 2012. 

The TSO precluded the use of hook and 

loop fasteners as a primary means of 

securing an ELT in its mounting tray for 

future ELT designs. TSO–C91a was 

previously cancelled, and a revision was 

not needed. 

(3) Determined need for an 

Airworthiness Directive to correct ELTs 

with hook and loop fasteners. The FAA 

accomplished a Corrective Action 

Review Board (CARB) to determine if 

existing airworthiness approvals and 

existing Technical Standard Order 

authorizations required 14 CFR part 39 

Airworthiness Directive (AD) action. 

The CARB determined an AD was not 

warranted. 

(4) Cease airworthiness approval of 

ELTs with hook and loop fasteners. Not 

necessary. Manufacturers with ELT 

designs incorporating hook and loop 

fasteners which failed to perform their 

intended function in accidents either 

have revised or are in the process of 

revising their designs, minimizing the 

need for policy in this area. 

(5) Withdrawal of ELT TSO 

Authorizations. Not pursued. 

Manufacturers with ELT designs 

incorporating hook and loop fasteners 

that failed to perform their intended 

function have either revised or are 

revising their designs, minimizing the 

need for this action. 

Conclusion 

The FAA issued an SAIB providing 

ELT installation and maintenance 

guidance and revised TSO–C126a to 

eliminate hook and loop fasteners from 

future TSO designs. The FAA is not 

issuing an airworthiness directive or a 

policy disallowing installation approval 

of ELTs that use hook and loop 

fasteners. Lastly, the FAA decided not 

to take the action of withdrawing the 

TSO authorizations of ELTs utilizing 

hook and loop fasteners as a mounting 

mechanism, but ask those aircraft 

owners/operators with ELTs secured 

with hook and loop fasteners in their 

aircraft to voluntarily switch to a metal 

strap type restraint method. Therefore, 

the proposed June 30, 2014 date for 

TSOA withdrawals is no longer 

applicable. 

Issued in Washington, DC, on March 4, 

2015. 

Susan J.M. Cabler, 

Acting Manager, Design, Manufacturing, and 

Airworthiness Division, Aircraft Certification 

Service. 

[FR Doc. 2015–05500 Filed 3–9–15; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

Underwater Locating Devices 

(Acoustic) (Self-Powered) 

AGENCY: Federal Aviation 

Administration, FAA, DOT. 

ACTION: Notice to extend the revocation 

date of Technical Standard Order (TSO) 

C–121 and C–121a, Underwater 

Locating Devices (ULD) (Acoustic) (SelfPowered). 

SUMMARY: This Notice extends the 

planned revocation date of Technical 

Standard Order (TSO) authorization for 

the production of Underwater Locating 

Devices (ULD) (Acoustic) (Self-Powered) 

manufactured to TSO–C121 and TSO C– 

121a specifications. This action is 

necessary to facilitate an efficient 

transition to UDLs with a 90-day 

minimum battery operating life 

manufactured to the TSO–C121b 

specifications. 

FOR FURTHER INFORMATION CONTACT: Mr. 

John Barry, AIR–130, Federal Aviation 

Administration, 470 L’Enfant Plaza, 

SW., Suite 4102, Washington, DC 20024. 

Telephone 202–267–1665, Fax 202– 

267–8589, email: john.barry@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Background 

The FAA published a Notice in the 

Federal Resister, 76 FR 52734, August 

23, 2011, announcing the planned 

revocation of TSO–C121 and TSO– 

C121a. Notice of that conformation was 

published in the Federal Register, 77 FR 

13174, March 5, 2012. Thus far, only 

two manufacturers currently hold TSO 

authorizations (TSOAs) under TSO– 

C121 or TSO–C121a; both are domestic. 

Both manufacturers are now authorized 

to produce longer duration TSO–C121b 

units as envisioned by the March 5, 

2012 Federal Register notice. One 

manufacturer received its TSO–C121b 

authorization in December 2014, the 

other in February 2015. Although both 

manufacturers received approval to 

manufacture devices meeting the 

current standard, the TSOA by itself 

does not authorize installation in an 

aircraft. Recent events have driven 

additional testing requirements for 

installation of lithium batteries, which 

these devices contain. Prior to the 

FAA’s issuing the TSOAs to the two 

applicants, testing of the lithium 

batteries produced satisfactory results, 

such that the newly approved TSO– 

C121b devices will contain the effects of 

catastrophic battery failures. The ULD 

manufacturer’s data may be used to 

support installations of the device on an 

aircraft, but each installer must analyze 

their design for safety impacts on their 

aircraft. A major aircraft manufacturer 

requested additional time to complete 

testing and analysis of the TSO–C121b 

device’s installation. They also 

requested additional time to update 

their part numbers and drawings in 

their various Type Certificated (TC) 

aircraft once the analysis is complete. 

Granting this additional time will 

prevent a disruption in aircraft 

production as the necessary 

documentation changes are updated to 

reflect the current production of TSO– 

C121b devices. 

Conclusion 

Based on the recent award of TSO– 

C121b authorizations, additional testing 

and analysis of lithium battery 

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Federal Register / Vol. 80, No. 46 / Tuesday, March 10, 2015 / Notices 12699 

installations and the lead time required 

to update required documentation, the 

FAA has delayed the revocation of 

TSO–C121 and TSO–C121a 

authorizations to December 1, 2015. 

Issued in Washington, DC. on March 4, 

2015. 

Susan J. M. Cabler, 

Assistant Manager, Design, Manufacturing 

and Airworthiness Division, Aircraft 

Certification Service. 

[FR Doc. 2015–05501 Filed 3–9–15; 08:45 am] 

BILLING CODE 4910–13–P 

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