Pilot's Guide to Avionics 2017-2018 - 54
MOVING ONWARD ON PART 23
Continued from page 53
four-place high-wing all-composite design with looks from
the future and performance beyond all competitive designs flying today.
With Flight Design's approach for a Part 23-approved
aircraft - embraced in the Part 23 rewrite proposal - mixing non-TSO systems in a glass cockpit with full WAAS
GPS instrument capabilities saves the planemaker, by
its own estimates, in the neighborhood of $30,000 to
$40,000 on the cost of building the aircraft.
Meanwhile, figure on further savings for future improvements the planemaker expects to be offered - absent the
sort of certification costs and expenses one might normally
expect and the FAA's simplified and slimmed-down certification process under the proposed Part 23. Aircraft and
avionics makers predict a future market with new, innovative and lower-cost private aircraft.
Interestingly, the planemaker behind this approach to
fielding an all-new aircraft employed the ASTM approach
to fielding the CT line of light-sport aircraft, arguably the
most-successful of nearly 140 different LSAs approved
under an ASTM-sanctioned, FAA-accepted self-certification and compliance program.
Flight Design USA's president and chief executive officer, Tom Peghiny, said the flexibility imbued in this approach helps the company hold to the $250,000 price tag
the company cited on launch of the aircraft in 2012.
"What we're accomplishing with the C4 follows exactly
the goals of the Part 23 rewrite," Peghiny said, "to bring affordable, modern technology to aircraft cockpits - cockpits
that people can afford to own and fly."
Part 23.1301: Unapproved parts
were already allowed
As explained by Ric Peri, AEA vice president for
government and industry affairs, many general aviation
manufacturers and owners have a misconception about
equipment requirements for IFR flight. And the FAA backs
up his contention in Advisory Circular AC-23.1311-1.
In section 8.0 for flight displays per section 8.1c for instrument requirements, the FAA says this:
c. The basis for certification has been that the equipment should perform its intended function and not present
a hazard. Instruments that aid situation awareness should
be certified under the Part 23 requirements, including §
23.1301 and § 23.1309. These displays could provide
hazardous misleading information. PFI is essential for
safe operation. An instrument that provides PFI (primary
flight information) should meet the minimum standards of
applicable TSOs or an equivalent standard. It also should
meet the guidance in AC 23.1309-1E, AC 23-17C, and the
guidance in this AC.
It does not say that in most cases the instruments must
be TSO'd or otherwise approved - only that the instrument
"should meet the minimum standards of applicable TSOs
or an equivalent standard." A few exceptions do apply.
And Part 21 does, however, require a manufacturer to
produce the part under either TC (such as Flight Design)
or TSO, or PMA.
Elsewhere in Part 23, the FAA lays out the requirements for panel position, placards and power redundancy
that further mesh with the use of so-called unapproved
instruments. The most-important requirement is the ability of an instrument to continue operating absent power
from the aircraft - or, a second, otherwise redundant set
of instruments to provide the three As that are required:
attitude, airspeed and altimeter.
The ASTM standards applied to these various instruments for PFDs provide an equivalent level of performance assurance for the attitude, turn information, vertical and horizontal speed and altitude required.
"The misconception goes right up through some of the
FSDOs and other authorities," Peri said shortly after the
EAA and Dynon announced their successful effort to win
the STC allowing electronic replacements for mechanical,
analog attitude indicators.
Advisory Circular 23.1311.1C goes further in its attempt
to clarify what's allowed.
Take this example, section 8.2:
8.2 Primary Flight Information. PFI refers to those
functions or parameters that are required by the airworthiness and operational rules, such as airspeed, altitude,
attitude and heading (direction). It may provide other
information pertinent to guidance and fundamental control of flight, such as critical engine parameters. Attitude,
airspeed, altitude and heading (direction) are the PFI
required in § 23.1311(a)(3) and (5), and they must be
arranged according to § 23.1321 in the "basic T" arrangement. Direction should be heading with track presented,
if available as a selectable option. The horizon reference
line on the PFD should be at least 3.25 inches wide in
straight and level flight for integrated displays. This recommendation is not intended to prevent replacement of
mechanical instruments with an electronic display of a
similar horizon reference line.
In the case of Flight Design's C4, gaining approval of
the package that includes noncertificated equipment -
which still meets performance standards - moved closer
to finality with the changes incorporated into the Part 23
Flight Design as pioneer
With the selection of Garmin avionics for its C4 fourplace EASA/Part 23 aircraft, Flight Design confirms two
major features it expects to make the C4 aircraft popular, successful and more affordable than other aircraft
in its class.
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