737 MAX Flight Crew Operations Manual
Flight Management, Navigation -
Company Data Link
11.33.2
MN-FLT-OH-201
Data Link
Downlinks are data link messages transmitted to a ground station. Requests for
data and reports of FMC information are two types of downlinks. Requests are
made manually by the flight crew. Reports can be made manually or may occur
automatically.
Uplinks are messages transmitted to the airplane. Most uplinks require manual
selections by the flight crew. Some uplinks are input automatically.
Manual Downlinks
Select a REQUEST prompt to start the downlink request for data. REQUEST
prompts are on PERF INIT, PERF LIMITS, TAKEOFF REF, PROGRESS, DES
FORECASTS, RTE, ALTERNATE DEST, RTE DATA, and SUPP NAV DATA
pages. Downlink reports of the active route may be accomplished by selection of
the REPORT prompt on the PERF LIMITS or PROGRESS page and a position
report may be downlinked by selection of the REPORT prompt on the
PROGRESS page. The contents of the supplemental navigation database can be
downlinked by selection of the REPORT prompt on the SUPP NAV DATA page.
When the communications function is unable to process FMC downlinks, the
words FAIL, VOICE, NO COMM, or FULL are displayed on the CDU pages in
place of the REQUEST and REPORT prompts and the header line displays the
word DATALINK. The status messages are:
• FAIL – the ACARS management unit is inoperative
• VOICE – radio is operating in the VOICE mode
• NO COMM – radio is operational but not available
• FULL – all available downlink space is full.
March 1, 2021
