Avionics News August 2014 - 54

SAFETY PRODUCT PROSPECTS
Continued from page 53

little time and too little altitude for recovery.
At pattern altitude and below, the outcomes are toooften fatal. Why do pilots still struggle to be inside safe
speed margins?
Certainly, the stall warning systems in Part 23 should
provide a margin of safety; but only a regular pilot will
know with confidence whether any given aircraft's really
works accurately. Further, the ASI suffers with its own
shortcomings in stall-avoidance situations.
Neither the stall horn nor the ASI compensate for
density altitude, G-loading or attitude.
As a rule, AoA systems make for accurate response
with indication consistently reflecting the aircraft's
margin in pitch before the onset of a stall - regardless of
attitude or ambient conditions.
The FAA sees the increased situational awareness from
AoA systems as a way to address a frequent accident
cause. "A lot of our fatal accidents (in general aviation)
are related to low-speed loss of control," Schinstock said.
In the words of a retired professional certified flight
instructor who spent years as a business-jet designated
examiner, "The AoA doesn't fool around and isn't
fooled. It will tell you you're close to stall angle-ofattack while the airspeed needle shows you're still 10, 12
knots away. An AoA gives the pilot an honest, consistent
cushion and a bigger window to react and indicate a
trend toward stall well before stall."
Organizations from the NTSB, the FAA, pilots and
business aviation groups, all indicate their intent to
focus on reducing LOC accidents through a number of
techniques and tools.
The option to supplement the ASI and stall-warning
device with a graphic, often audible, indication with the
new angle-of-attacks gives these safety advocates a tool
new to the rank-and-file piston-aircraft owners but one
with an established track record and respect earned from
thousands of flight-deck professionals: airline pilots,
business aviation flight crews and military aviators.
The FAA's February approval of the ASTM standards
for installation of complaint, nonrequired angle-of-attack
indicators is an example of the possibilities emerging from
the years-long Part 23 rewrite now coming into play.
"We're pretty excited," said Ric Peri, AEA vice
president of government and industry affairs. "We are
seeing the future and are moving ahead, and not just here."
54

avionics news

august

2014

ASTM F3011-13: Genesis for GA angle-of-attack
Install it; log it; calibrate it; and fly it. This new
safety-product opportunity - for which any Part 23/
CAR (Canadian Aviation Regulations) 3 aircraft is
eligible - may not sound like an attractive business
opportunity ... at first blush.
But the actual "install" portion of the process
requires more time and labor than implied.
The expected push to expand AoA use in a war
on errors against LOC accidents will likely yield
significant numbers of pilots interested in adding AoA
to aid their efforts.
ASTM F3011-13, the document, finalized and
submitted to the FAA for review last year, sets
compliance standards and performance requirements,
as well as limits on how these systems can interface
with the aircraft's systems. For example, an audiopanel connection to use a system's audible-warning
feature is a simple connection and allowed under the
standard the FAA accepted in February.
But a need to interface with a flap-position sensor
takes the system to a different place - and beyond the
ASTM consensus rule the FAA approved.
This leaves what essentially is a simple package to
install, a process complicated more by the architecture
of the airframe than the complexity of the system.
Here's a snapshot:
Three-part package
These common-architecture packages require
installing and connecting three basic common
components: First, a stand-alone air sensor with two
pitot-tube-like air-pressure tubes connects to the
second component, a central processing brain with
a pressure transducer and other electronics, which
in turn must connect to a cockpit display, the third
common component.
The package can interface with the host aircraft's
electrical system for power and, if the option is
employed, to provide power for a heated sensor (to
keep it ice free).
The other connection also is optional, albeit
desirable - wiring the main brain's audio-out
connection to the host aircraft's audio panel to provide
crew with audible warnings to change pitch.
This new safety-enhancement option opens a way
for avionics and maintenance shops to help their
customers add a safety enhancement to their flight

Avionics News August 2014

Table of Contents for the Digital Edition of Avionics News August 2014