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A Recipe for SD

A Recipe for SD

COMPILED BY THE KNOWLEDGE STAFF

Low-risk missions continue to produce accidents. Whether these missions cause crewmembers to conduct less-detailed mission plans or become more relaxed in the cockpit with their peers, pilots must plan carefully and accurately, taking into consideration all possible hazards encountered from initial takeoff to final landing.

During a helicopter accident in the desert, a low-risk mission claimed several Soldiers’ lives. One unit member referred to the mission as a “milk run,” meaning it was supposed to be a simple flight from Point A to Point B. Of all the missions this unit was about to execute, this flight into the area of operations should have been the easiest they would encounter. Unfortunately, it proved to be more hazardous than originally planned.

So why did a seemingly low-risk flight turn bad? The crew onboard the aircraft appeared to be an adequate mix for this mission. However, a flaw in the risk assessment tool used by the unit allowed two pilots with very little recent night vision goggle flight experience to fly together at night over some of the most difficult terrain. The pilot in command had more than 200 NVG hours — although very few of those hours were in the months leading up to the accident. He had acquired less than a half-hour’s training during environmental training in theater. The pilot was a new aviator and had fewer than 50 NVG hours.

When unit leadership paired this crew, the 1,000-hour PC appeared to be a good choice to crew with the inexperienced PI. After all, it was just a “low-risk milk run.” Because of the low-risk mentality, the unit also front-loaded the more experienced instructor pilots into the first serials. This left the last serial with fewer experienced leaders.

What else did this low-risk flight have going against it? The crews in the flight had been waiting for days for a dust storm to subside. The night of the accident, dust hung in the air and weather conditions were at the absolute minimums for the mission profile. Add to that the fact the flight would be crossing a desolate area of desert with little or no vegetation or artificial light on the horizon to provide contrast between earth and sky. Incorporate those conditions with minimal NVG training in the low-contrast environment and you have a recipe for spatial disorientation, or SD.

Crewmembers of the other aircraft in the flight described bouts with SD. Nonrated crewmembers told stories of losing the horizon and having to look down at the ground to try to trace it back up to the horizon. They described episodes of SD that required them to bring their attention inside or close their eyes to fight it. Pilots described the horizon as one big green blob and one described it as purely an instrument flight. Yet a common theme prevailed: No one spoke up about the inability to see or SD.

What happened?

The flight was a formation of four aircraft, cruising at 120 knots and 650 feet above ground level. As the crew of Chalk 2 began to encounter SD and strayed to the left of formation, Chalk 3 followed. When Chalk 2 corrected back to the right, Chalk 3 continued its left turn, gradually increasing its bank angle and nose-down attitude until ground impact. Witnesses stated the aircraft made no sudden directional changes and appeared to fly into the ground. The board concluded the crew encountered SD and crashed.

Lessons learned

There are important lessons to learn from this accident.

  • Good crew mix. When planning for missions, it is a good idea to divide the experienced aviators among the flights and aircraft. When assigning crews, leaders and trainers should take into account pilot experience level — including the recency of that experience — for all the flight conditions that may be encountered.
  • Risk assessment worksheet. Scrutinize risk assessment tools for comprehensiveness and accuracy. Several investigations have revealed flawed risk assessment tools, ranging from a lack of flight mode experience choices, to worksheets that can only equal low risk. On one automated worksheet, the only option that populated the overall risk block was a low risk. There were no other options in the formula for the cell.
  • Crew coordination. There was a definite breakdown in crew coordination among the crews and between aircraft. Despite the fact crewmembers from each aircraft experienced SD or difficulty seeing the horizon, no one said anything until after the crash. Chalk 2’s ability to recover from its SD can be attributed to the effective crew coordination that took place in that aircraft after the onset of SD.

How do we combat SD?

Training in the flight modes and environments in which we encounter SD is probably the best way. Use simulation devices to train for riskier situations, such as inadvertent instrument meteorological conditions, overwater operations and low-contrast desert environments. Use heads-up display devices to help maintain focus outside the aircraft. Conduct classroom training on the signs and symptoms of SD and provide information and techniques to overcome it if encountered. During the crew brief, discuss the actions to take should you lose situational awareness. Pilots should incorporate nonrated crewmembers into the plan. Lastly, all crew members should conduct positive and continuous crew coordination between crews and aircraft to prevent SD. Remember, SD can happen to anyone.

  • 10 July 2016
  • Author: Army Safety
  • Number of views: 1139
  • Comments: 0
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