Avionics News July 2017 - 26
USB PANEL POWER
Continued from page 25
Both USB power ports can be hardwired into the panels
of type-certificated aircraft. Certified under TSO C-71,
"Airborne Static (DC to DC) Electrical Power Converter
(For Air Carrier Aircraft)," Appaero's Stratus Power Port
is approved for aircraft certificated Part 23 and Part 25.
Guardian iFD 150R and 250 received the first Federal
Aviation Administration approval under the Non-Required
Safety Enhancing Equipment program, which authorizes
their installation in Part 23 aircraft up to 12,500 pounds
(and Part 27 and Part 29 rotorcraft) as a minor alteration.
Stratus Power features two 2.5-amp USB Standard-A
charging ports that accept 10 to 32 input volts. USB power
was the common denominator in several Stratus ADS-B
support cases, according to Aslakson. Either the Stratus
wasn't charging or something was interfering with other
avionics, and the solution was a USB panel power port
"designed for use in the cockpit."
Meeting the TSO requirements ensured its cockpit
compatibility. Those requirements, he continued, include
the DO-160 tests for overvoltages, radio frequency
emissions, and short circuit conditions, among others,
in various environments of high and low temperatures,
humidity and altitudes with different degrees of vibration.
Reverse polarity is only possible if the unit is hardwired into the aircraft incorrectly. According to Aslakson,
should that happen, "Stratus Power is designed so that it
will not work, even if you leave it for days." Installation
also determines whether Stratus Power is energized when
the aircraft is not running. "Most people wire it into the
avionics bus, and pilots can verify its operation by looking
for the charging icon on the device plugged into it."
Citing hardware and installation as the dominant cost
factors in certified avionics, Appareo "focused on the
installation details during the design process," Aslakson
said. Dealers said their biggest challenge was cutting
rectilinear holes in the panel, so Stratus Power has a
cylindrical shape that easily fits in a 1.25-inch hole
"anywhere you have room on the panel," he said. "It
mounts from the back and the faceplate screws on from the
front and pinches the panel, and that's it."
Recognizing that panel space is always at a premium,
Guardian offers a variety of mounting options for its iFDR
Power, according to Keough. It has two faceplates, a round
one for a standard cigarette lighter opening - out with the
old and in with the new in the same opening - and a square
that requires a 0.785-inch cutout.
"The iFDR also features a green LED backlit port for
easier use at night," Keough said. "And the iFDR is now
certified for 2.7 amps, so it will power the big 12.9-inch
iPad Pro and Microsoft Surface."
The system grew out of Guardian's research and
development of a new generation of USB powered
products, carbon monoxide detectors, cockpit applications
that fed data via USB to a tablet, and a power supply for
devices held by panel-mounted cradles. Seeking NORSEE
approval from the FAA's Small Airplane Directorate was
the most effective, efficient and cost-effective way to
approve the USB panel power for Part 23 aircraft.
"We contacted the Small Airplane Office to discuss the
design in its early stages, before submitting the request, so
the FAA could determine that it qualified for NORSEE,"
Keough said. The FAA established NORSEE policy in
March 2016. It does not bypass existing certification
processes or FAA oversight, but it standardizes the
approval process specific to it. NORSEE equipment can
increase overall situational awareness, provide additional
information and/or independent warning, cautionary or
advisory indications. And it can provide additional safety
protection for the aircraft's occupants.
NORSEE design requirements are based on applicable
industry standards established by ASTM, RTCA, SAE
and others. Past that hurdle, Guardian documented the
equipment design with drawings, specifications, part
numbers, its functional capabilities and characteristics,
performance parameters, accuracy, installation and
maintenance instructions, and operating limitations.
"After running a lot of tests, we provided all the
documentation for FAA evaluation," Keough said.
Summarizing the details of the evaluation, he said the
FAA wanted to verify "that the failure state would not
affect anything else in the airplane." Guardian's NORSEE
approval letter covers all of Guardian's USB-related power
The last component in a reliable, well-shielded system is
the cable that connects the device to the panel's USB power
supply. "Most cables that come with the device do not
have adequate shielding," said Keough, adding that it also
depends on the sensitivity of the installed avionics. "We
provide MFi (made for iPhone/iPod/iPad)-certified cables
with our iPad and iPhone cradles that are hardwired into
the power supply and terminate with an Apple Lightning
Several providers, such as Sporty's Pilot Shop,
stock shielded USB cables for devices that pilots most
commonly use in flight, and in the interests of safety,
keeping a spare in the cockpit will reduce the stress and
frustration when a pilot's search for it in the cockpit or
flight bag comes up empty. q