Goodbye, Mode-C
The Federal Aviation
Administration has released details of its plans to mandate Mode-S
transponders on all new aircraft certified under Parts 121 or 135,
and to phase in the new technology on older aircraft when the
Mode-C (or even older Mode-A) transponders on those airplanes wear
out.
Mode-S transponders have actually been around since 1975, but
only recently has the industry been able to benefit by differences
over the more common Mode-C technology. Mode-S -- for "Select
Beacon System" -- transponders constantly transmit an aircraft's
location (including whether the airplane is on the ground, or in
the air) and altitude to ATC, with greater precision (within
25-foot increments with some systems) than Mode-C. This precision
is better suited to today's multi-function displays (MFDs) and
traffic collision avoidance systems (TCAS).
Mode-S transponders also transmit an aircraft's N-number.
Below is the text of an Aircraft Electronics Association (AEA)
Regulatory Update outlining the FAA's plan.
SUBJECT: FAA PROPOSES
TO TERMINATE MODE S TRANSPONDER EXEMPTIONS FOR PART 135
OPERATORS
REFERENCE: Federal Register dated October 7,
2005, Page 58967
SUMMARY: The FAA proposes that all FAA
authorized exemptions of 14 CFR 121.345(c) and 135.143(c) terminate
no later than March 1, 2007. The FAA will not be granting any new
exemptions after March 1, 2007.
MAJOR HIGHLIGHTS: The FAA proposes that
all existing FAA authorized exemptions of 14 CFR 121.345(c) and
135.143(c) terminate no later than March 1, 2007. The FAA will not
be granting any new exemptions after March 1, 2007.
This proposed date would provide affected operators with
approximately 18 months to install a Mode S transponder if
necessary under Sec. Sec. 121.345(c) and 135.143(c).
Under paragraphs (c) of Sec. Sec. 121.345 and 135.143,
after January 1, 1992, only Mode S transponders may be newly
installed in U.S. registered civil aircraft. Under these
regulations, the term "installation" does not include: (1)
Temporary installation of a Mode C transponder or substitute
equipment as appropriate, during maintenance of the permanent
equipment; (2) reinstallation of equipment after temporary removal
for maintenance; or (3) for fleet operations, installation of
equipment in a fleet aircraft after removal of the equipment for
maintenance from another aircraft in the same operator's fleet.
Consequently, the FAA proposes that effective March 1, 2007, if
a transponder needs to be permanently replaced it must be replaced
with a Mode S transponder.
The FAA notes that if the operator was issued an exemption
before March 1, 2007, allowing them to install a Mode C transponder
on their aircraft, they may continue to use that transponder until
it no longer can be repaired and must be replaced with a Mode S.
Therefore, if they hold an exemption, any Mode A or C transponder
that is installed on or before March 1, 2007, may remain in their
aircraft and may continue to be repaired after March 1, 2007. When
that Mode A or C transponder can no longer be repaired, it must be
replaced with a Mode S transponder.
Comments must be filed no later than November 7, 2005.
NTSB Final Report: Patriot Aircraft LLC CX1900A
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