The C-130 missions to the north have since ended, but Marine and now Army Chinook and Black Hawk helicopters have also been flying in food and other aid to inaccessible parts of the Swat Valley and Kohistan from an air base in Ghazi. Swat was the scene of a massive Pakistan Army campaign against Taliban insurgents last year, and Kohistan is famous as an inaccessible, deeply impoverished and conservative mountainous corner that rarely sees foreign visitors.
Threading heavy loads through rocky valleys
The system is set up as a straightforward temporary logistics support operation, moving people and material as long as daylight lasts and security and weather conditions allow. The planes and helicopters move whatever the Pakistanis ask them to carry, including food, supplies, people and sometimes even livestock.
All military personnel said they have received a warm welcome.
"The first couple weeks, it seemed like people were pretty excited to receive our help," said Capt. Noble, who had been flying up and down the Swat Valley for a month. "Every time we dropped off stuff, 45 minutes later, when we come back, it was gone, so obviously people are using what we dropped off."
But the relative simplicity of their operation and the hospitality shown by their hosts masks the very real dangers that can be involved, most often just from the elevation and jagged terrain.
"For our airframes, we're flying them right at max gross weight, so there's a very narrow power margin," Army officer French explained. "There's very little margin for error to land, and that could be caused both by the weight of the aircraft, the altitude that we're flying at, and also the very narrow valleys."
After a refueling stop at a helipad in Pathan, Kohistan, a pair of Army Black Hawk helicopters made their way farther north up the Indus River Valley by the Kashmiri border. The smaller Black Hawks are needed here because there are very few convenient or workable landing spots -- at one point, the pilot set the helicopter down on a rocky ledge right next to raging whitewater rapids, the rotor spinning just a couple of feet from a massive rock-face wall.
The approach to Gilgit can be equally perilous, depending on the weather.
Regarded as one of the more dangerous airports in the world, the Gilgit landing can only be reached by flying through one narrow valley, negotiating a 90-degree turn left around a mountain into another valley and another 90-degree turn to the right to line up with the airfield. Any sign of bad weather, even slight fog, will see the air crew calling off the approach.
"You can't see down the direct line of sight to the field until you make it around this peak, which is a pretty high peak," said 1st Lt. Glenn Ryberg, a Marine Corps C-130 airplane pilot.
Guarded landings, but warm receptions
The terrain Ryberg and his crew must negotiate on a daily basis is harrowing. The view from the cockpit of the plane, already flying at 21,000 feet in elevation, shows mountains on both sides still towering well above it. When crews see that they are flying below these peaks, that's when they know they are at the "go/no-go" point, Ryberg said.
"Once you determine that it's OK to descend, which means there are no clouds in the valley, we'll come down on this corner, and that's really where you kind of make the final decision if you're going to continue," he explained. Ryberg added that the Marines are flying this route because the Air Force deemed it too dangerous for their pilots to try it, though he believed approval would come soon.
The noise of aircraft and security precautions made it impossible to ask locals how they felt about the assistance provided by U.S. troops. But the warm smiles and enthusiastic waves and handshakes traded at every drop-off point suggested that the affected communities are happy to get any help they can, regardless of who the donor is.