User's Guide
Table Of Contents
- 1 Introduction
- 1.1 Audience
- 1.2 Overview
- 1.3 Envoy CMU Features
- 1.4 Configuration Options for Envoy
- 2 Operation of Envoy
- 3 CPDLC Operations
- 3.1 Log On
- 3.2 Logoff
- 3.3 Lost Connection
- 3.4 Typical Message Composition
- 3.5 ATC Menu
- 3.5.1 ATC Request Menu – FANS 1/A+ and ATN B1 CPDLC Common
- 3.5.2 ATC REPORT Menu
- 3.5.3 WHEN CAN WE EXPECT
- 3.5.4 POS REPORT Message – FANS 1/A+
- 3.5.5 EMERGENCY (MAYDAY) Message – FANS 1/A+
- 3.5.6 ATC MSG LOG
- 3.5.7 CLEARANCE REQUESTS – FANS 1/A+
- 3.5.8 FREE TEXT 1/2
- 3.5.9 ATC VOICE CONTACT Message – FANS 1/A+
- 3.5.10 Cancel EMERGENCY, Cancel ADS
- 3.5.11 Flight Plan Transactions and Monitoring
- 4 Automatic Dependent Surveillance (ADS)
- 5 ACARS Operations
- 6 MAINTENANCE Menu
- Appendix A Acronyms
- Appendix B AFN Messages
- Appendix C Supported CPDLC Messages
- Appendix D ADS-C Tags
- Appendix E ACARS Message Labels
- Appendix F ATSU Call Signs (ICAO, IATA)
- Appendix G Fault Management
User Guide for the Envoy Data Link
Document Number: UG-15000 Rev. A Page 25 of 173
established VHF frequency, and upon connection, the scratchpad displays an advisory message,
VHF ESTABLISHED, as shown in Figure 2-7 Establishing a COMM Link at Start Up.
Figure 2-7 Establishing a COMM Link at Start Up
The availability of a VHF data link determines which messaging protocol is available for CPDLC
logon.
Table 2-3 Link Media
Messaging Protocol
Link Media Supported
ATN B1 CPDLC
VDL Mode 2 required. (No function over VDL Mode 0/A or SATCOM)
FANS 1/A+ CPDLC, ADS-C
VDL Mode 2, VDL Mode 0/A, or SATCOM
ACARS
VDL Mode 2, VDL Mode 0/A, or SATCOM
2.5.1 VHF Multi-Frequency Support
The Envoy tracks up to 20 in-range ground stations to provide optimal VHF connectivity. The
Envoy supports multi-frequency operation based on signal strength, configured preferences, and
the flight plan. Sophisticated algorithms track the signal strength of available/preferred ground
stations, based on departure/destination airports for the current flight, configuration settings, and
provider network (SITA or ARINC) in the current COMM mode. Available/preferred stations display
in the Station Table; the current station is indicated with an asterisk. For additional detail, see
Section 6.6
On startup, if the previous frequency or ground station is unavailable, or if a connected ground
station fails to respond to a downlink after several attempts, the Envoy seeks other VHF ground
stations, scanning company-configured lists of VHF Mode 2 and Mode A frequencies in order to
establish an active COMM link.
VDL Mode 2 uses the Common Signaling Channel (CSC) frequency and Ground Station
Information Frame (GSIF) to balance COMM traffic loads. If the Envoy is directed to an alternate
frequency, the Envoy automatically re-tunes and connects to the alternate frequency.
If VHF COMM is not responding to an ACARS downlink, the Envoy automatically shifts from VHF
to SATCOM, if equipped, to transmit the message. In SATCOM mode, the Envoy continues to
search for VHF ground stations.
All of this is transparent to the aircrew.