By Alastair Leithead
BBC News, Afghanistan
Helicopter crews provide a lifeline to troops fighting the Taleban, raising dust clouds in the desert as they ferry supplies, evacuate the wounded - and come under fire themselves.
The small group of British troops holding the position on the hill had an hour's worth of rations left when the Chinook supply helicopter dropped its load of food, water and ammunition close by.
They had been on the operation for more than 48 hours and had been fighting the Taleban in the "green zone" - the area of thriving vegetation along the Helmand River.
The Taleban fight from among the marijuana fields with plants standing two metres high, from the high-walled, thick mud compounds and from the dense tree lines.
Bayonets are fixed and ambush can come any time, but it can be as dangerous for the helicopter crews re-supplying the infantry and flying into battlefields to pick up the injured.
"I was mortared last week coming into land," said Flight Lieutenant Stuart Hague, a pilot with 1310 Flight of the Joint Helicopter Force.
"It was about 50 to 100m in front of where we were coming into land - enemy fire is a considerable threat at the moment. It's the small arms, the rocket-propelled grenades, which you can't see coming, but that's part of the job now."
Tracer fire can be seen at night but during the day helicopter crews often do not even know they are being shot at until they are hit.
The twin-rotor RAF Chinook helicopters are the workhorses of the campaign in Helmand, and across southern Afghanistan where the Joint Helicopter Force operates.
They are escorted by Army Apache helicopters, which can react to any attack from the ground. The Apaches are also used to support infantry troops - air power is a vital part of the counter-insurgency.
British, American and Dutch helicopters work together in the Regional Command South region of Afghanistan, which includes Helmand, and is run by a British headquarters.
And they do regularly come under fire. "Man pads" - surface to air missiles - have been fired at International Security Assistance Force aircraft over the past few months, but it is the "lucky shot" with a rocket-propelled grenade which has brought down at least one Chinook.
The view from the Chinook
It is not just enemy fire which is a danger to the helicopters.
"The biggest threat by far is the environmental threat," said Flt Lt Hague. "We have to land usually on unprepared sites which are very dusty, so for the last 30 feet you can't see where you are going. Darkness is another key factor, of course, because we have to fly 24 hours a day."
And landing in the desert can be dangerous. As our own helicopter came close to the ground, the whole cabin filled with the fine dust-like sand. Visibility was down to zero.
It is often at night when the medical teams are called out to bring in injured soldiers, and sometimes civilians caught up in the fighting.
Crew members say they do not remember ever bringing in as many casualties as they have over the past couple of months - the fighting in Helmand and Uruzgan, where Dutch forces are based, has recently been very intense.
Life-saving treatment can be given in the back of a helicopter as it rushes back to the British field hospital at Camp Bastion.
Picking up the injured can be traumatic, said Flight Sergeant Antony Raymont, crewman with the Joint Helicopter Force.
"We get quite a range of injuries out here from simple things like road accidents - sometimes people who have been injured in bombs or whatever - so it can be quite graphic. But you get on with your job and don't tend to think about it while you are flying.
"When you come back we all talk about it as a crew and often go up to the hospital afterwards and talk to the medics about it and get it out of our systems."
The hours are long and the crews have to watch each other to make sure they do not get over-tired.
Flt Lt Hague said the current pace was not sustainable: "We could do with more crews, and the training system is hopefully going to deliver that in the near future.
"The helicopters do get tired because they are working in such a harsh environment. The engineers could certainly do with more support because they are working flat out, and we have to monitor their fatigue levels as well as they work such long shifts."