80 FR 12697 - Emergency Locator Transmitters (ELTs)

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration

Federal Register Volume 80, Issue 46 (March 10, 2015)

FAA evaluated five separate courses of action with regard to the airworthiness approvals for securing ELTs with hook and loop fasteners. This notice summarizes the inadequacies of hook and loop fasteners as a means for securing ELTs, and avoids placing an undue burden on aircraft owners while acknowledging the voluntary efforts of ELT manufacturers to improve designs.

[Federal Register Volume 80, Number 46 (Tuesday, March 10, 2015)]
[Notices]
[Pages 12697-12698]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2015-05500]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Emergency Locator Transmitters (ELTs)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice recommending voluntary change to securing existing ELTs 
as specified in Technical Standard Order (TSO)-C126b, 406MHz Emergency 
Locator Transmitter.

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SUMMARY: FAA evaluated five separate courses of action with regard to 
the airworthiness approvals for securing ELTs with hook and loop 
fasteners. This notice summarizes the inadequacies of hook and loop 
fasteners as a means for securing ELTs, and avoids placing an undue 
burden on aircraft owners while acknowledging the voluntary efforts of 
ELT manufacturers to improve designs.

DATES: Comments must be received on or before April 9, 2015.

FOR FURTHER INFORMATION CONTACT: Ms. Charisse R. Green, AIR-131, 
Federal Aviation Administration, 470 L'Enfant Plaza, Suite 4102, 
Washington, DC 20024. Telephone (202) 267-8551, fax (202) 267-8589, 
email to: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    Investigations of some recent aircraft accidents disclosed that 
ELTs mounted with hook and loop fasteners became dislodged from their 
mounting trays on impact. The separation of those ELTs from their 
mounting trays caused their antenna connection to sever, thus rendering 
the ELTs to be ineffective and unable to perform their intended 
function.
    The FAA Modernization and Reform Act of 2012 (Pub. L. 112-95), 
Section 347(b)(1), required the FAA to determine if the ELT mounting 
requirements and retention tests specified by TSO-C91a and TSO-C126 
were adequate to assess retention capabilities in ELT designs. Based on 
the determination, the Act, in Section 347(b)(2), required the 
Administrator to make any necessary revisions to the requirements and 
retention test to ensure ELTs remained properly retained in the event 
of an aircraft accident.
    The FAA evaluated the mounting requirements and retention tests 
specified in TSO-C91a, TSO-C126, and TSO-C126a. After this evaluation, 
the FAA determined these standards did not adequately address the use 
of hook and loop fasteners. Hook and loop fasteners were not an 
acceptable means of compliance to meet the mounting and retention 
requirements of the ELT TSOs. While the evaluation of installation 
approval using hook and loop fasteners may meet the TSO requirements 
for retention forces in laboratory conditions, accident investigations 
found these fasteners did not perform their intended function.

FAA Concerns

    The agency identified the following concerns after completing its 
evaluation of the use of hook and loop fasteners:
    (1) Hook and loop fasteners fail to retain the ELT when 
insufficient tension is applied to close the fastener. There is no 
repeatable method for installation and no method to evaluate the 
tension of the hook and loop fastener. The allowance for pilots to 
secure ELTs to the aircraft when changing ELT batteries

[[Page 12698]]

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