Army elite can drop in anytime, day or night
And a team of elite Army commandos in the Irish Defence Forces have been perfecting their own "fast-roping" skills in a series of day and night-time training exercises over the past year.
In the most recent night-training session at The Curragh in Co Kildare, the elite team of 10 Army Rangers rappelled 100ft from an AW 139 Air Corps helicopter as part of a joint training programme.
The exercise in fast-rope insertion was filmed using nightvision video cameras and has been posted on YouTube by the Defence Forces' online magazine.
The dramatic footage shows pilots using nightvision glasses as the Rangers slide down the rope within seconds.
"It's done completely in the dark for surprise attacks at night," Army press officer Commandant Denis Hanley told the Irish Independent.
The technique aims to get the soldiers deployed on the ground as quickly and quietly as possible.
In these photos taken last year, the same helicopter hovers above a Dublin-Holyhead ferry on the Irish Sea as Rangers practise their rappelling skills while the helicopter crew in the night-time exercise operate in the dark using nightvision goggles.