In August 2019, the dam of Toddbrook Reservoir in Derbyshire started to crack.
Days of heavy rain led to rising waters and a fear it would be completely breached, threatening the town of Whaley Bridge below. Local authorities asked the military to help.
A Chinook and its crew were tasked with completing a unique mission to help secure the dam with bags of aggregate.
"It was pretty shocking the amount of damage nature can actually do to something that looks incredibly sturdy and has been there for hundreds of years," Chinook Pilot from 27 Squadron, Flight Lieutenant Matthew Smyth, said.
"It's a really difficult skill [that] these guys have got," Wing Commander Gary Lane told Forces News in August 2019.
"The request to us has been pretty prescriptive and we're almost delivering it into sort of millimeter-specifics here," he added.
Whaley Bridge was evacuated.
There was a genuine fear that if the dam burst, the town would be swept away.
The crews from 27 and 18 Squadrons at RAF Odiham, along with their ground support teams, knew the stakes were high.
"The biggest issue we found was when we got to the dam itself," Sergeant Gav Anderson from 27 Squadron said, "There was actually a handrail that went along the top edge of the dam and we had to maintain a 10ft clearance. So to get low enough to accurately position the loads we were finding it really quite tough," he added.
"It's not something that we are trained to do. We don't practice releasing the loads that high, so I was happy that the first time we did it the loads went in the correct places," Sergeant Oli Squire, from 18 (B) Squadron said.
Hour after hour, the Chinook went up and down the valley picking up the next load, dropping it and repeating.
"The team on the ground came up with an idea to use spray-paint cans to create a grid system onto the dam. We would then get passed information over the radio [of where to drop the bags]," Sergeant Squire added.
"It became a giant game of Battleships."
It was tiring work, physically and mentally, but the community rallied round.
"They just looked really tired and like they needed a pick-me-up, so we took a load of vanilla slices, scones, chocolate brownies, anything we could and wheeled them down through a secret alleyway to try and get to them," Camilla Dignan, who works at the Bridge Bakehouse in Whaley Bridge said.
"They were trying to save the village and we just wanted to give back."
"The response of the local population was absolutely outstanding," Flight Lieutenant Smyth said.
The residents remember the Chinooks in Whaley Bridge and show appreciation for the effort with car stickers, giant lanterns, banners made at the time, and the local pub now stocking Chinook ale.
The bags of aggregate are still at Whaley Bridge. The reservoir itself has been emptied, awaiting the rebuild.
Wing Commander Gary Lane went back with Forces News and said the experiences here will shape future operations.
"It is [about] understanding what we did - the good points of what we did - and reflecting on how we worked together as a team and how we can fine-tune that to work even better for the next call that we get," Wing Commander Lane said.
Whaley Bridge is now open for business, with locals forever thankful to the Chinook, the RAF and all the emergency teams that came to their rescue.
For their efforts, 18 and 27 Squadrons from RAF Odiham won the 'Hero at Home - Unit' award at The Sun Military Awards.
Watch extended highlights of the Millies on Wednesday 12 February at 18:30 UK time on Forces TV, and at 19:10 UK time on BFBS Extra.
Cover image: RAF Chinook helicopter aids efforts to protect residents near Whaley Bridge in August 2019 (Picture: MOD).