
[Federal Register Volume 77, Number 135 (Friday, July 13, 2012)]
[Notices]
[Pages 41473-41475]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-17115]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Proposed Technical Standard Order (TSO)-C126b, 406 MHz Emergency 
Locator Transmitters (ELT) and Notice of Intent To Withdraw TSO 
Authorizations (TSOA) for TSO-C91a, Emergency Locator Transmitter (ELT) 
Equipment, and TSO-C126/C126a, 406 MHz Emergency Locator Transmitters 
(ELT)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of availability and request for public comment.

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SUMMARY: This notice announces the availability of proposed TSO-C126b 
and the FAA's intent to withdraw TSO authorizations (TSOA) issued for 
the manufacture of automatic fixed (AF) and automatic portable (AP) 
ELTs under TSO-C91a, TSO-C126, and TSO-C126a which incorporate hook and 
loop fasteners in their design. This proposed action would affect ELT 
manufacturers. The FAA is not proposing requiring actions on previously 
installed ELTs. The FAA is taking this action based on its 
determination that hook and loop fasteners are not an acceptable means 
of compliance to meet the mounting and retention requirements of 
current TSOs for ELTs. The FAA is requesting comment on proposed TSO-
C126b and the FAA's proposal to withdraw certain other ELT TSOAs.

DATES: Comments must be received on or before September 11, 2012.

FOR FURTHER INFORMATION CONTACT: Ms. Charisse Green, AIR-130, Federal 
Aviation Administration, 470 L'Enfant Plaza, Suite 4102, Washington, DC 
20024. Telephone (202) 385-5637, fax (202) 385-4651, email to: 
Charisse.Green@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    You are invited to comment on proposed TSO-C126b and the proposed 
withdrawal of TSOAs for the manufacture of automatic fixed (AF) and 
automatic portable (AP) ELTs under TSO-C91a, TSO-C126, and TSO-C126a 
which incorporate hook and loop fasteners in their design by submitting 
written data, views, or arguments to the address specified in FOR 
FURTHER INFORMATION CONTACT. If you propose alternate actions, please 
provide detailed information on your alternative and indicate whether 
the information you provide is proprietary. Comments received may be 
examined, both before and after the closing date at Federal

[[Page 41474]]

Aviation Administration, 470 L'Enfant Plaza, Suite 4102, Washington, DC 
20024., weekdays except Federal holidays, between 8:30 a.m. and 4:30 
p.m. The Director, Aircraft Certification Service, will consider all 
comments received on or before the closing date.

Background

    In several recent aircraft accidents, ELTs mounted with hook and 
loop fasteners, commonly referred to as Velcro[supreg], have detached 
from their aircraft mounting tray. The separation of the ELT from its 
mounting tray has caused the antenna connection to sever, rendering the 
ELT ineffective and severely impacting the performance of the TSO'd 
ELT.
    Section 347 of the FAA Modernization and Reform Act of 2012 (Pub. 
L. 112-95) requires the FAA to determine if the ELT mounting 
requirements and retention tests specified by TSO-C91a and TSO-C126 are 
adequate to assess retention capabilities in ELT designs. Based on that 
determination, the Act requires the Administrator to make any necessary 
revisions to the requirements and retention tests to ensure that ELTs 
are properly retained in the event of an aircraft accident.

Evaluation of ELT Mounting Requirements and Retention Tests

    The FAA evaluated the mounting requirements and retention tests 
specified in TSO-C91a, TSO-C126 and TSO-C126a. These TSOs specifically 
address ELT mounting and require the mounting design to meet certain 
specifications; however, they do not require or preclude any specific 
type of retention mechanism. Based upon its evaluation, the FAA has 
determined that the standards contained in these TSOs do not adequately 
address the use of hook and loop fasteners. While these types of 
fasteners can meet the TSO requirements for retention forces in 
laboratory conditions, accident investigations have found these 
fasteners are not reliable in service.
    Recent accident data reveals hook and loop fasteners have failed to 
retain the ELT in its mount. The following three documents describe 
specific accidents in which an ELT failed to remain its mount after an 
accident:
    (1) NTSB Aircraft Accident Report AAR-11-03: The antenna cable was 
severed from the ELT when the ELT slipped out of the hook and loop 
fastener which retained the ELT to the installed mount. The ELT 
functioned properly during post accident testing by the manufacturer 
and NTSB. As a result of its investigation the NTSB made safety 
recommendation A-10-170 to the FAA which stated: ``Determine if the 
emergency locator transmitter mounting requirements and retention tests 
specified by TSO-C91a and TSO-C126a are adequate to assess retention 
capabilities in ELT designs. Based on the results of this 
determination, revise, as necessary, TSO requirements to ensure proper 
retention of ELTs during airplane accidents.''
    (2) NTSB Factual Report--Aviation NTSB ID WPR10FA273: The antenna 
cable was severed from the ELT when the ELT slipped out of the hook and 
loop fastener which retained the ELT to the installed mount. The ELT 
functioned but without the antenna the transmissions were not strong 
enough to be received by the search and rescue satellites.
    (3) Transportation Safety Board of Canada Aviation Safety Advisory 
A11W0151-D1-A2, Loose Attachment of Kannad 406 AF-Compact (ER) ELT. 
This advisory highlights an October 2011 Cessna 208B accident where 
inadequate installation of the hook and loop fastener resulted in the 
ELT sliding out of its mount, disconnecting from the antenna cable, and 
failing to perform its intended function.
    Both government and industry guidance material discourages the use 
of hook and loop fasteners and notes potential difficulties with their 
use in ELT mounting. Advisory material discouraging the use of hook and 
loop fasteners includes the following:
    (1) Advisory Circular AC 91-44A, Operational and Maintenance 
Practices for Emergency Locator Transmitters and Receivers, paragraph 
6.a., states that attachment of ELTs solely by means of Velcro[supreg] 
strips and other flexible materials is not considered satisfactory 
since the ``g'' switches may fail to operate or the equipment may come 
out of its mounting resulting in damage to the ELT and possible damage 
to the antenna or antenna coaxial cable.
    (2) RTCA DO-DO-182, Emergency Locator Transmitter (ELT) Equipment 
Installation and Performance, section 1.2 a., states that ELTs secured 
with Velcro[supreg] strips are an improper installation.
    (3) NASA Technical Memorandum-81960, Evaluation of Emergency- 
Locator-Transmitter Performance in Real and Simulated Crash Tests, 
states: ``Typical mounts can vary from sturdy mounts, to mounts using 
Velcro[supreg], plastic ties, and mounts on non-airframe structure in 
the airplanes. This diversity in mounting techniques include improper 
and/or inadequate mounting of many ELT's and is likely to be one source 
of problems of nonfunctioning and/or false activations of some units.''

FAA Concerns

    After completing its evaluation of the use of hook and loop 
fasteners for ELT retention the agency identified the following 
concerns:
    (1) Hook and loop fasteners fail to retain the ELT when 
insufficient tension is applied when closing 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 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 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.
    (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.
    Safety Awareness Information Bulletin (SAIB) HQ-12-32, Hook and 
Loop Style Fasteners as a Mounting Mechanism for Emergency Locator 
Transmitters, was issued May 23, 2012 to bring immediate attention to 
this issue. It outlines actions ELT manufacturers can take to improve 
their installation and maintenance instructions to mitigate the 
concerns with hook and loop ELT retention.

Determination

    The FAA has determined that hook and loop fasteners are not an 
acceptable means of compliance to meet the mounting and retention 
requirements of the current ELT TSOs.

Proposed Actions

    Based on its evaluation, the FAA proposes to:
    (1) Issue TSO-C126b which would preclude the use of hook and loop 
fasteners as a means of securing an ELT in its mounting tray.
    (2) Withdraw TSO authorizations issued for the manufacture of ELTs 
under TSO-C91a, TSO-C126 and TSO-C126a, which incorporate hook and loop 
fasteners into their design unless the design is revised to replace the 
hook and loop fastener with an alternative

[[Page 41475]]

acceptable to the FAA before June 30, 2014.
    (3) Withdraw TSO authorizations issued for the manufacture of ELTs 
under TSO-C91a, TSO-C126, and TSO-C126a, which incorporate hook and 
loop fasteners into their design unless the installation and 
maintenance instructions for the article are revised to include the 
following information by June 30, 2013:
    a. Detailed instructions for properly securing the ELT during 
installation and reinstallation, as well as a method to determine the 
appropriate tension of the hook and loop style fasteners. Revised 
instructions will provide improved guidance on the proper installation 
of ELTs for owners and operators in the interim period before an 
enhanced mounting design is available, and for owners and operators who 
choose not to install the enhanced mounting design when it is 
available.
    b. Detailed instructions for inspecting the hook and loop style 
fasteners for wear, contamination, environmental degradation, and other 
effects to ensure they meet the standards of the applicable TSO.
    c. A replacement interval for the hook and loop style fasteners.
    (4) Encourage owners and operators to install the manufacturer's 
proposed updated mounting designs in accordance with the revised 
maintenance and installation instructions.

How To Obtain Copies

    You can view or download TSOs C91a, C126, C126a by logging onto 
http://rgl.faa.gov and select Technical Standard Order, and the 
proposed TSO-C126b may be found at http://www.faa.gov/aircraft/draft_docs/tso/. For a paper copy of the documents, contact the person listed 
in FOR FURTHER INFORMATION CONTACT.

    Issued in Washington, DC, on July 10, 2012.
Susan J. M. Cabler,
Assistant Manager, Aircraft Engineering Division, Aircraft 
Certification Service.
[FR Doc. 2012-17115 Filed 7-12-12; 8:45 am]
BILLING CODE 4910-13-P


