Floating easily over the steep mountains of Yakima Training Center, Washington, the twin rotor CH-47 Chinook gracefully carried the massive weight of an M777 howitzer cannon and its crew toward their destination. Their mission was to drop in, quickly set up their guns and suppress simulated enemy air defense, allowing infantry units to advance forward with the help of close air support.

This training was the first time that 1st Battalion, 37th Field Artillery Regiment, 3-2 Stryker Brigade Combat Team tested their howitzer crews, who have been training for months, with a full-scale air raid mission that culminated with firing live rounds.

The training, which took place during the day and night over the course of a week and began Oct. 21, was the culmination of countless hours of practice and numerous others training events all building up to this.

"We're conducting what is called a gun raid," said Chief Warrant Office 2 Brandon Alvarez, a target acquisition platoon leader who helped plan the training. "A gun raid is when you set up the M777, 155mm cannons at ... a pickup zone, the helicopters come and pick them up and carry them forward. It simulates moving (ahead) of the forward line of troops.

Due to rapid speed with which infantry units, and particularly Strykers, can advance, it can be tough to keep artillery in a beneficial position that allows them to support their unit by providing fire. Gun raids help balance this difference by allowing the howitzers and crews to rapidly advance and provide fire wherever they are needed. This is done through technique known as sling loading, which allows the cannons to be rigged safely to the bottom of a Chinook helicopter.

>>> A CH-47 Chinook lifts an M777 howitzer as soldiers from 1st Battalion, 37th Field Artillery Regiment, 3-2 Stryker Brigade Combat Team, watch during training at Yakima Training Center, Wash., Oct. 21, 2014. Photo credit: Staff Sgt. Justin Naylor

"If the infantry is rolling out and we can't keep ahead of them, then we need to be sling loaded ahead of them," Alvarez said. "We provide our own security, we get down and we shoot emergency missions."

For this particular training event, the unit simulated passing ahead of the farthest line of infantry troops and being emplaced in a position to fire on enemy air defenses.

"We're going to pass them, land and suppress the enemy air defenses so that our air cover can come in and our infantry can envelop," Alvarez said.

This mission is different than a traditional air movement, but the terms are often used interchangeably.

"The point of an air assault as opposed to an air movement-the two terms are confused quite a bit-in an air assault, the purpose is to give the ground tactical commander an advantage of enveloping the enemy before they have time to react," Alvarez said. "If you can see Strykers coming, you have time to formulate at least a small plan if you're an enemy commander. If you see a helicopter, especially if it's flying into the wind, you're not going to hear it until it is maybe 500 or 600 meters out and by then it's too late to formulate a plan. You're in a reactive stance by that time."

In the real world, missions like this happen quickly and require a great amount of technical expertise from both the ground and helicopter crews.

"Rigging it only takes 20 minutes, they can de-rig it enough to fire it in 15 minutes and then be rigged back up within 35 minutes of landing and be ready to come back," Alvarez said. "So why do they need three days to rehearse? Because they rehearse anything that could possibly go wrong. ‘Hey, what if this doesn't work? What if the ground is too thick to dig in? What if the sight breaks?' They rehearse that over and over and over until it is second nature."

This training is particularly important to the unit because Stryker units don't typically conduct air raid missions, so it required a lot of prior planning and coordination, said Alvarez.

"The first thing they did ... is procure air assault items," said Alvarez, a Boise, Idaho, native. "In Stryker units, you just don't have that stuff, so we had to find a way to get sling sets, tape ... all the things you need. Next, we had to find experts, so we went down to the unit and said, ‘Hey, who's been to air assault school, who has been to pathfinder school?'"

After identifying those individuals, they relied on them to teach others within their units how to properly rig and prepare equipment for air assaults.

"Then they brought helicopters in and did what's called an elevator," Alvarez said. "That's when a helicopter comes in and picks a load up for a couple of seconds and sets it down and lets it loose. And then another crew would come in and practice setting up, and then another crew, and another crew and they would rig and de-rig."

Alvarez said that this initial training constituted the crawl phase, which indicates that it is the first in a series of events that all build on previous training.

"The end of the crawl phase was learning how to hook their piece of equipment up and being comfortable with it and proficient at it and everybody knowing their piece," Alvarez said. "Right now I would say we're in the walk phase; it's the first time the unit is doing an air raid with a helicopter, so they're going to see how fast it moves, how it lands."

This is the chance for the unit to see if all of their prior planning works as hoped and to identify areas that need to be adjusted in the future.

"Once we do this, we're going to be coming back to Yakima in a few months and we're going to do a tactical plan, where we'll get an order and the men won't know they're air assaulting," Alvarez said.

During that training, the soldiers will provided with only minimal advanced notice of the air assault and will be expected to put their previous training into action.

"What do we want them to get out of it?" Alvarez asked. "We want them to be able to be in their sleeping bag in an assembly area, get woken up at 2 in the morning and told that they're going to air assault a gun raid at 4 a.m. and say ‘OK, it's too easy, we've done it, we know how to rig it ... we are ready."

To Alvarez, training like this gives soldiers a sense of purpose and a better knowledge of why they are doing a particular mission.

"The soldier is going to follow orders, but it's better that they know exactly why they are doing something because it means more and it makes them want to do it more."

Staff Sgt. Justin Naylor is with the 3-2 Stryker Brigade Combat Team Public Affairs.

>>> Soldiers with 1st Battalion, 37th Field Artillery Regiment fire an M777 howitzer during training at Yakima Training Center. Photo credit: Staff Sgt. Justin Naylor