Degraded Visual Environment: What are you going to do about it?

By Chief Warrant Officer 4 Jimmy Hagerty, Accident Investigator, USACRCAugust 7, 2017

DVE
Degraded visual environment is defined as an environment of reduced visibility of potentially varying degree, wherein situational awareness and aircraft control cannot be maintained as comprehensively as they are in normal visual meteorological condi... (Photo Credit: U.S. Army) VIEW ORIGINAL

FORT RUCKER, Ala. (August 7, 2017) - What do a brigadier general, a private first class, every warrant officer rank, some Marines and Airmen all have in common? They all have families, friends, and fellow Soldiers that continue to mourn their loss. They are just a few among the 129 individuals who were fatally injured in Army aviation accidents that occurred while operating in a degraded visual environment (DVE) since 2002.

The majority of those accidents took place at night. We are all well versed on the limitations of our night vision googles and how our vision is degraded compared to flying during the day. If you further reduce our visual cues with snow, dust, fog, low illumination, etc., you have seen what the result can be. This is why it is so important to focus our actions when we encounter DVE, especially at night.

You may be thinking, "That will never happen to me." Tragically, the following is an example of a crew who likely felt the same way. Unfortunately, they were not able to overcome the challenges present while operating in DVE.

It was a dark night. What illumination the cloud cover did not block out the fog took care of. They knew it was going to be crappy out, but it was only a few miles to the LZ.

"It's freakin' dark out here."

"I'm having a hard time seeing anything."

"Crap, I think we just punched in!"

"What's up with your airspeed?"

"What are you doing?"

"Watch your attitude."

"Watch your map, you're spinning!"

"Z-axis plunge!"

"It's not working!"

"You take the controls!"

"Watch your power!"

"We're in a sharp turn!"

"We're diving! Pull up, pull up!"

If I told you the crew that perished that night was a new pilot in command and a low-time co-pilot, your first reaction would probably be anger. "Why in the world would anyone approve that crew to fly under those conditions? I can't believe they were even allowed to take off!" You might even think, "I wouldn't take off in that weather at night unless someone's life was hanging in the balance."

If there was a pilot that had to do the mission, you might be the one. You're a master Army aviator, a standardization pilot, and have over 4000 flight hours. Even still, you would grab the strongest co-pilot you could, the most experienced crew chiefs, and your commander would still ask you a dozen times if you and your crew were comfortable with this. Your pride would well up inside of you, and you would tell your commander, "No sir, I'm not comfortable, but we have to try. We have troops in contact. They're black on ammunition and we are their only hope."

There have been times where Army aircrews have gone to extraordinary efforts to save the lives of their fellow service members. Sadly, the story I am telling now, was not one of them. We cannot get angry over the poor crew mix on this one, because they were not low-time or low-experience aviators. They were some of the most experienced aviators at the commander's disposal. While we do mourn their loss, it was not because they were risking their lives in combat to save others in great peril. They were CONUS, conducting training that could have been done at a later time when weather was suitable.

This article is not intended to point out every mistake that led up to this tragic night. I want to impress upon you how an experienced crew can fall victim to the dangers of operating in DVE. How many times have you made a comment to your other crew members about the crummy weather that you were looking at as you walked out to the aircraft?

Maybe the weather was legal, but it sure was not ideal. You strap in, take off, and your mission is underway. Then the comments start up. "It's dark as crap out here tonight." "We can't even see one mile mountain with this yellow dust today." "It's a lot foggier than what weather was calling for." All of these comments are key indicators that your crew knows that your visual environment is now more degraded than it was. The question is, "What are you doing about it?" When a crewmember comments that visibility is worse than it was earlier in the flight or worse than you expected to encounter, does that trigger something amongst the crew? If I called out to the crew, "I'm inadvertent on the left!" that would immediately alert the crew to the emergency situation we were in. There would be no confusion about what I am trying to communicate to the rest of my crew. There would also be no question as to what I expect the crew to do and what they expect of me.

When we encounter DVE, we usually do not think of it as an emergency. We think of it as abnormal or simply not business as usual. We may not feel the change in condition poses an immediate threat to our crew. When we communicate the change to the crew we typically say it in a casual way; they may acknowledge the change, but are not overly concerned. Chances are we have all flown in worse conditions, and our plan is to just suck it up and drive on. Unfortunately, many of the fatalities pointed out earlier in this article resulted from aircrews turning a less than optimal situation into an actual emergency; an emergency they were not able to recover from.

What if we applied a level of structure when encountering a DVE the same way we structure our actions during other emergencies? I'm not suggesting we squawk 7700 and lock our inertia reels, but I am suggesting a change in the way we are scanning and possibly flying at the moment we encounter DVE. The cockpit recording you read earlier was a crew that made comments about the DVE, never took appropriate action and allowed themselves to get into an emergency situation. Once they were in the emergency situation, inadvertent instrument meteorological conditions (IIMC), they never acknowledged it. Had they acknowledged they were IIMC, they likely would have taken the immediate steps to ensure a successful recovery of the aircraft, crew, and their passengers. However, I think we need to back up even further from the actual emergency. What if the dialog went something like this:

PC: "It's dark as crap out here."

PI: "Definitely darker than I was expecting."

PC: "All right guys, we've definitely encountered DVE."

CE: "Roger, Sir. DVE."

PC: "All right, let's review our scan. Attitude is good; let's not do any rapid turns or banks. Altitude; I want to keep the ground in sight, so maintain this altitude. Heading; we've got some wires coming up. Call Chalk 2 and let them know we are coming around to the right. Airspeed; keep it at a slow hover, go ahead and Z-axis plunge. We will fly coupled back to the PZ. Torque; is good. Trim; you're good."

Just like announcing that you are IIMC, announcing that you have encountered DVE draws the entire crew's attention to the change in conditions. While it is not an emergency, going through a procedure that reinforces the pilot's scan may prevent one. It also causes the entire crew to adjust their scan and back up the pilot on the controls. When I flew over water off the coast of Honduras, I would always brief my crew chiefs to monitor the radar altimeter and alert me if I went below our set hard deck. I knew they had as much riding on a safe flight as I did and frankly, I appreciated the help while flying over the water.

Here is the hard part. What constitutes DVE and when should I announce to the crew I am encountering it? If I were to go IIMC, there is no confusion about when it happens. While another crew member may not be IIMC, I know that I am and I immediately announce it. With DVE, it may be something as subtle as increased dust in the air and the visibility decreasing from unrestricted down to 5 miles. Your flight profile may not need to be adjusted, but announcing the condition and subsequent review of the crew's scan needs to happen. If the dust picks up and the visibility drops to 3 miles, announce the DVE and have the conversation again. It may sound redundant, but I guarantee a good aviator is already having a conversation about the reduction in visibility with the crew. Now we are just applying a procedure to the condition you are already discussing.

There is no master list of what conditions constitute DVE. The definition is vague, as there are many things that could cause reduced visibility. As defined in the capabilities development document (CDD) from TRADOC Capabilities Manager-Aviation Brigades (TCM-AB), degraded visual environment is defined as:

An environment of reduced visibility of potentially varying degree, wherein situational awareness and aircraft control cannot be maintained as comprehensively as they are in normal visual meteorological conditions (VMC) and can potentially be lost.

Put simply, when you are flying along and someone in the crew or flight makes a comment about the worse-than-expected or deteriorating weather or conditions, you are experiencing DVE. The reduced visibility, at some level, is affecting or may soon affect your crew's situational awareness and/or aircraft control. This may sound elementary, but if it were, I would not be writing this article and we would not have 129 individuals who have died in the past 14 years with DVE as one of the conditions present.

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