7 seconds i believe. Enough if you get used to it.
Not enough for crew weapons when consider huge AoE.
Timer has 10secs, but bomb lands around 13secs.
You can hear sound around 6-7sec (which leaves 9sec to land)
Then you have 2-3sec to find where it's gonna hit and move units out (6sec before land)
If you used for this 4sec you are doomed thanks to huge AoE.
For units like pack howie it is insta death 9/10 times.