```

[Federal Register Volume 77, Number 120 (Thursday, June 21, 2012)]
[Notices]
[Pages 37470-37471]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-15209]

=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

Technical Standard Order (TSO)-C65a, Airborne Doppler Radar 
Ground Speed and/or Drift Angle Measuring Equipment (for Air Carrier 
Aircraft)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of intent to cancel Technical Standard Order (TSO)-C65a, 
Airborne Doppler radar ground speed and/or drift angle measuring 
equipment (for air carrier aircraft).

-----------------------------------------------------------------------

SUMMARY: This notice announces the FAA's intent to cancel TSO-C65a, 
Airborne Doppler radar ground speed and/or drift angle measuring 
equipment (for air carrier aircraft).
    The effect of the cancelled TSO will result in no new TSO-C65a 
design or production approvals. However, cancellation will not affect 
current production of articles with an existing TSO authorization. 
Articles produced under an existing TSOA can still be installed per the 
existing airworthiness approvals, and all applications for new 
airworthiness approvals will still be processed.

[[Page 37471]]

DATES: Comments must be received on or before July 23, 2012.

FOR FURTHER INFORMATION CONTACT: Mr. Albert Sayadian, AIR-130, Federal 
Aviation Administration, 470 L'Enfant Plaza, Suite 4102, Washington, DC 
20024. Telephone (202) 385-4652, fax (202) 385-4651, email to: 
albert.sayadian@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    You are invited to comment on the cancellation of the TSO-C65a by 
submitting written data, views, or arguments to the above address. 
Comments received may be examined, both before and after the closing 
date at the above address, 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

    The Doppler radar ground speed and/or drift angle measuring 
equipment described by this TSO was used to provide inputs to 
semiautomatic self-contained dead reckoning navigation systems which 
were not continuously dependent on information derived from ground 
based or external navigation aids. The system employed radar signals to 
detect and measure ground speed and drift angle, using the aircraft 
compass system as its directional reference. This approach is less 
accurate than Inertial Navigation Systems (INS), and the use of an 
external reference is required for periodic updates if acceptable 
position accuracy is to be achieved on long range flights. Use of INS 
and Global Positioning System (GPS) has rendered TSO-C65a Doppler 
sensor equipment that provides inputs to dead reckoning navigation 
systems obsolete.
    On August 18, 1983, the FAA published TSO-C65a, Airborne Doppler 
radar ground speed and/or drift angle measuring equipment (for air 
carrier aircraft). The FAA has no record of any TSO-C65a applications 
from 1990 onward. Our research indicates no new TSO-C65a applications 
are in progress, and no authorized manufacturers are manufacturing, 
advertising, or selling TSO-C65a compliant equipment. Given the 
obsolescence of the equipment, and the lack of industry interest in new 
TSO-C65a product designs, we propose cancelling TSO-C65a.

    Issued in Washington, DC, on June 18, 2012.
Susan J.M. Cabler,
Assistant Manager, Aircraft Engineering Division, Aircraft 
Certification Service.
[FR Doc. 2012-15209 Filed 6-20-12; 8:45 am]
BILLING CODE 4910-13-P
```