RT-2087/ZPX-A User and Installation Guide
UAV-1005667-001 Rev A
ECCN 7A994
Page 41 | 48
A.1.2
Heartbeat Message
With UCP enabled, the Heartbeat message is sent once per second. The
following specific fault indications are available in the Heartbeat message,
and should be mapped to annunciations compliant with applicable
regulations. TSO-C166b requires annunciations of ADS-B transmission
device and function failures (see RTCA/DO-260B §2.2.11.5)
Fault
Description
Maintenance Required
ICAO address not set (RTCA/DO-181E §2.2.10.3)
ICAO address not set (RTCA/DO-260B §2.2.11.3.1)
Multiple position sources available
– check configuration
(RTCA/DO-260B §2.2.5.3)
Failure TX System
Transponder replies not enabled or acquisition squitter rate
failure (RTCA/DO-181E §2.2.10.4)
Transmit not enabled or extended squitter rate failure
(RTCA/DO-260B §2.2.11.2.1 and §2.2.11.5.1)
Failure GNSS
No 3D Fix
No valid 3D position from GNSS (RTCA/DO-229E §2.1.2.6)
Failure GNSS
Unavailable
Unable to communicate with GNSS subsystem (RTCA/DO-
260B §2.2.11.6)
A.2
UCP-HD
uAvionix Control Protocol
– Half Duplex (UCP-HD) is documented in
uAvionix UCP Transponder Interface Control Document
UAV-1002375-001
(Rev. T or later). This document is available to authorized parties and may
be obtained by contacting uAvionix.
UCP-HD can be used to configure, control, and monitor status of ZPX-A .
A.2.1
Control Message
See A.1.1 for a description of the Control message.
A.2.2
Transponder Status
With UCP-HD enabled, the Transponder Status is sent in response to each
Control message, as documented in the ICD.
The presence of a fault to annunciate is delivered by the “Fault or Failure
Indicated” bit being set. To determine the specific fault, query the Heartbeat
message using a Message Request. See A.1.2 for a description of the fault
indications available in the Heartbeat message.
