"I'm Inadvertent IMC!"
August 23, 2011
About two hours before launch, we received our weather brief and were informed that we could expect excellent visibility and no ceilings during our flight. However, there was a thunderstorm building in northeast Iraq, but it was not considered a hazard to us. We were briefed for a 1,000-3 (1,000-foot ceiling and 3 statute miles of ground visibility) night vision goggle (NVG) flight because we would be returning after dark under goggles. We had executed this mission many times in the past weeks and considered it routine.
As we neared takeoff time, there was some confusion with arrival times of the DART recovering the Chinook. They showed up on the ramp unorganized and searching for lost equipment and personnel. After this convoluted episode, we were 45 minutes behind schedule, but this wasn't a time-dictated mission. During the start-up process, flight lead experienced a maintenance issue that set us back two hours, requiring us to fly goggles through evening nautical twilight. We received a new brief and updated weather report and launched to accomplish the mission.
The flight was uneventful until we were about 20 miles south of the FOB. At that point, we noticed lightning north of the FOB and discussed this with the other aircraft. We concluded the lightning was far enough away to not be a threat and only visible because we were wearing NVG. Flight lead made the tower call and cleared us to the forward arming and refueling point (FARP) to refuel and then reposition to parking to wait for the Chinook to trail us back south.
As we neared the FOB, tower notified us the FARP was closing due to lightning. However, we persuaded them to remain open long enough for us to refuel. On final, tower again radioed and requested our intentions after refuel. They stressed weather was approaching the FOB and we didn't need to loiter long in the landing zone. Through our Blue Force Tracking, we received approval to leave the DART team and return to base without the Chinook, as our battalion did not want two UH-60s to remain overnight.
Following refuel, we repositioned and began unloading personnel and equipment. We noticed the wind was increasing and there was dust in the air. Tower, at this point, was adamant we take off shortly and not remain on the ground long. Following flight ready calls, flight lead called tower requesting a "present position takeoff" departing to the south, which was approved.
The wind continued escalating with visibility diminishing due to dust. Flight lead picked up and turned to the south for departure. I was in the left seat, looked left and noticed the buildings and lights began to disappear in the oncoming haboob. Tension was building in the cockpit and I knew my pilot was hesitant to take off.
After a few seconds of discussion, he announced I could have the controls. I knew at this point if we did not take off, flight lead would be flying single ship back to base because it was impossible for them to return to parking. I announced I had the flight controls and departed with an immediate right turn toward the south. I still had visibility and my right-rear crew chief (CE) had eyes on flight lead and was verbally clearing my right turn.
All of a sudden, everything disappeared. We were engulfed in the haboob at about 200 feet above ground level. My CE announced he could not see anything. With seconds seeming like eternity, I announced I had inadvertently entered instrument meteorological conditions (IMC) and initiated the proper procedures. The only thing on my mind was to stop turning, level the aircraft and, most importantly, climb.
After about 30 seconds, the horizon began to appear and visibility improved as we exited the haboob. Just as fast as we were engulfed, we were in an unrestricted visibility environment heading south.
As a young PC, this event was a pinnacle in my career, allowing me to see just how fast a dangerous condition can occur. Following this event, I realized I had endangered my crew and myself by not choosing a more conservative course of action. I learned a lot from this experience. I tell myself to constantly learn every day; evaluate my options; make conservative, effective decisions; and strive to apply them to future operations.
w/ sidebar below
The Army has procedures that prepare us in the event that we go inadvertent instrument meteorological conditions (IIMC). We brief procedures with the crew before every flight. The aircrew training manual clearly states, step-by-step, what to do. Local standing operating procedures also provide guidance in case we accidentally punch into the clouds.
The Five C's
The Five C procedure is a fast-acting antidote to confusion and anxiety during the first 10 to 15 seconds after IIMC. It is within these critical seconds that the battle with IIMC is won or lost. If aircraft control can be maintained during this initial crucial period, the chances of surviving an IIMC experience are greatly enhanced.
Whether all Five C's will apply in each IIMC circumstance will depend on existing conditions (e.g., terrain, obstacles, etc.).
1. Control of the Aircraft: This is the most important factor in recovering from IIMC. You must convince yourself ahead of time that if you enter IIMC and lose ground reference, your only option is to immediately transition to instrument flight. Level the wings in the attitude indicator, maintain heading, adjust to climb power and adjust to climb airspeed. Once you make the transition, control is established by crosschecking the flight instruments. If you fail to make this transition, you're in serious trouble. The four subsequent C's depend on the successful accomplishment of this first C.
2. Coordination: Crews must discuss what each will do in case of IIMC. It should be understood that the pilot on the controls will concentrate on the instruments while the pilot not on the controls will back up the instrument scan, along with all his normal duties, and look outside for a place to land. When flying multiship, each aircrew must coordinate between flights.
3. Clearance: To ensure the highest terrain feature along the route of the flight will be cleared, gain altitude with a straight, controlled climb. Use minimum safe altitudes and low-illumination routes. In mountainous terrain, consider briefing multiship IIMC breakup to maintain heading and deconflict by airspeed and altitude.
4. Course: Select and turn to the appropriate heading or maintain heading as dictated by terrain.
5. Call: Make required radio calls for assistance. Coordinated radio frequencies should be specified and posted in the aircraft.