The most common and most likely answer to this crossword clue is the 11 letter word PARACHUTING
I've seen this crossword clue in The Times
P
A
R
A
C
H
U
T
I
N
G
Buddy explains!

The straight part
We know that "coming down" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case coming down = parachuting.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PARACHUTING mean?
PARACHUTING verb- To jump, fall, descend, etc. using such a device.
- To introduce into a place using such a device.
- To place (somebody) in an organisation in a position of authority without their having previous experience there; used with in or into.
- The sport of jumping with a parachute.