When Does "Alien: Advent" (2017) Take Place?
"Alien: Covenant - Advent" is a science fiction short film written by Will Melton that released August 15th, 2017. So when is "Advent" set?
It takes place on the fictional Alien vs. Predator timeline roughly in the year:
We know this because the first clear shot and the last clear shot includes the logo and name "WEYLAND-YUTANI CORP". The Weyland-Yutani Corporation, a company seen as two separate companies: the Weyland Corporation and the Yutani Corporation from "Alien vs. Predator" (2004), which takes place in 2004 AD, to "Prometheus" (2012), which takes place in 2093 AD. It must be after their merger. In the expanded elements novel "Alien: Covenant - Origins" (2017), which takes place in 2103 AD, Indri Mithun says, ..."there are some among the Weyland contingent who still feel the need to assert themselves." and, soon after, "Most who survive such mergers quickly resign themselves to their new circumstances. But for a few, bad feelings can linger." This means the merger that creates the Weyland-Yutani Corporation hasn't happened yet in 2093 AD and is still recent in 2103 AD. So it is very likely after 2103 AD.

~2104 AD
We know this because the first clear shot and the last clear shot includes the logo and name "WEYLAND-YUTANI CORP". The Weyland-Yutani Corporation, a company seen as two separate companies: the Weyland Corporation and the Yutani Corporation from "Alien vs. Predator" (2004), which takes place in 2004 AD, to "Prometheus" (2012), which takes place in 2093 AD. It must be after their merger. In the expanded elements novel "Alien: Covenant - Origins" (2017), which takes place in 2103 AD, Indri Mithun says, ..."there are some among the Weyland contingent who still feel the need to assert themselves." and, soon after, "Most who survive such mergers quickly resign themselves to their new circumstances. But for a few, bad feelings can linger." This means the merger that creates the Weyland-Yutani Corporation hasn't happened yet in 2093 AD and is still recent in 2103 AD. So it is very likely after 2103 AD.
More specifically, it is probably before the company is dissolved. During "Alien Resurrection" (1997), which takes place in 2379 AD, Dr. Mason Wren says, "Weyland-Yutani, Ripley's former employer." ... "Oh, they went under decades ago, Gediman, way before your time. Bought out by Walmart. Fortunes of war." So it is probably before 2359 AD.
"decades ago" = at least 20 years
and
2379 - 20 = 2359.
The short consists entirely of recordings the android David 8 is reporting on his activities from "Prometheus" (2012) to "Alien: Covenant" (2017), which takes place in 2104 AD. Between these two stories David was unable to transmit anything and it’s unlikely his extremely clinical mind would wait long to report his findings. It's most logical to place this found-footage short film when a viewer within the fictional universe (diegesis) of the film could first see it, in 2104 AD.
It is the tenth chronological short film in the Alien vs. Predator timeline and it can be watched at its timeline point.

