In 2006, I was deployed to Iraq with the 2-224th Aviation Battalion. The 224th is an assault battalion of UH-60 helicopters from the Virginia Army National Guard. I was a platoon instructor pilot with about 2,200 flight hours. We were under the command of Marine Expeditionary Force I and had replaced a squadron of Marine CH-46 helicopters. We were based at Al Asad Air Base in the western Al Anbar Province; however, our normal area of operations was from the Syrian and Jordanian borders in the west to Baghdad in the east.

We did the majority of our flying at night and landed primarily at airports or forward operating bases, although we occasionally landed at unimproved areas. Weather was always our main concern, as accurate reporting and observations were difficult to obtain. Ceiling and visibility could and would change with little to no warning. Visibility was particularly problematic because the sand and dust would kick up and sometimes hang in the air for days.
Another hazard at night was the level of illumination - or the lack thereof. When the sky is clear and the moon is full, it's very bright. However, when there was little to no moon, the sky is disturbingly dark. Add a little sandy, dusty haze to the mixture and you have to struggle to find even small visual cues. Yet, as we approached the cities and towns, their artificial lights helped considerably.
We had been in country for about eight months, knew the area well and were comfortable flying mixed aircraft operations with the Marines. On this particular night, I was flying with our S3. He was an experienced pilot in command but didn't have a lot of recent flight time due to his staff position. Nonetheless, I still had complete confidence in his judgment and flying ability.
We were Chalk 3 in a flight of three. Lead was a Marine UH-1 equipped with forward-looking infrared radar. Chalk 2 was another one of our UH-60 Army aircraft. We were flying west on a low illumination night. The visibility was above our minimum required; however, it was close enough to cause some discussion as to whether we should delay or cancel the mission.
As we flew into deteriorating visibility, I started to feel as if I were in an increasing left turn. It started slowly and was like nothing I had experienced before. I always knew to trust my instruments or, in this case, the heads-up display connected to my night vision goggles. Normally, any leaning sensation or spatial disorientation would be short-lived. Unfortunately, the sensation continued to worsen until I felt I was in about a 30-degree left turn. I continued to trust my instruments and attempted to fly through this condition, all the while hoping it would be temporary. At this point, I should have transferred the flight controls, but I didn't want to create a situation where my pilot (PI) had to do both his job and mine. Besides, we were flying straight and level and everything was working fine.
The weather began to worsen and we finally made the decision to abort the mission. I was OK as long as we made a nice, easy turn to the left, which is how I felt we were turning anyway. When lead announced he was making a 180 to the right, I told my PI, "No way." I stated there was no way I could turn right and maintain aircraft control. I then transferred the controls to him. We executed a slow climbing right 180 - much like an instrument meteorological condition breakup - because we lost sight of the first two aircraft. I think my PI was a little freaked out because there was little warning. The visibility improved as we climbed and we could easily see the lights of Al Asad in the distance.
We recovered without incident and had a thorough debrief. Although I should have done a better job of keeping my crew informed of my decreased ability, I think my training worked, as it should. As a pilot, it's important to recognize what is happening, trust the information your systems are providing, take action when you've reached your limit and rely on your crew to perform their jobs.