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December 7, 2016

Its What We Dont See That Scares Us

Helicopter Air Ambulance has a dark history. Several accidents have taken many lives over the past years, with the deadliest year being 2008.

By Nic Highfill, ThedaStar Lead Pilot

Helicopter Air Ambulance has a dark history. Several accidents have taken many lives over the past years, with the deadliest year being 2008. Many of these accidents were due to controlled flight onto terrain/obstacles. This rise in fatal accidents had initiated several meetings between the FAA and many of the operators in the United States. Discussions centered on night flights in deteriorating weather, risk management, complacency, helicopter shopping and use of night vision goggles (NVGs). The results of these meetings came in the form of new regulations pertaining to equipment needs and weather minimums, as well as policy changes that dictate how recurrent training is conducted.

Today we are required to have on board a helicopter terrain avoidance and warning system (HTAWS). This system alerts the pilot and crew when their current course/altitude will bring them into contact with terrain, radio/cell towers or wires. We also are required to know what the highest obstacle/terrain is along each leg of our flight so that we can calculate our minimum safe altitude (MSA). Our MSA is determined by adding 300 feet to the highest obstacle/terrain along the route for day flights, and adding 500 feet for night flights. We also NVGs for all night flights to enhance our awareness of obstacles and terrain. In addition, air carriers have used traffic collision and avoidance systems to increase the pilots’ awareness of other aircraft flying in close proximity.

The bottom line: The better you see, the better you can avoid danger. Imagine walking across a dark room in a house with which you’re unfamiliar. Can you easily navigate your way through without bumping in to a chair or table? What about walking across a dark room in your own home, a room you are familiar with? Even then, it is difficult.

These systems and processes work great for our cruise portion of flight. But what about landing on a roadside or in a field – at night – in rain or snow – with flashing red lights all around us? Wires are very difficult to see at night, even with NVGs. Road signs, when viewed from certain angles, are almost invisible as well. Loose debris, which can blow into the air and re-circulate through the rotor system, poses additional risks. That includes dirt, snow or dust that can restrict visibility during critical moments. The slope of the land also is an important consideration.

For this portion of the flight, we approach things with great care. We do a high reconnaissance orbit to identify risks. Once we determine our route, we start our low recon. This is to verify what we have seen and look for additional hazards. If something is seen at the last minute, there are specific crew call-outs used to help the pilot avoid striking something in flight. “HOLD” tells the pilot to hold the aircraft in place exactly where it is, allowing the pilot to find what is nearby and avoid it. “GO AROUND” tells the pilot the landing zone is unsafe and to try another approach or find a new landing zone.

Just as important as everything listed above is our communication with ground personnel. On scene, they will give us a detailed landing zone description to include all possible hazards and obstructions. We may not have seen the road sign from our high and low recons, but because the personnel on the ground advise us of it, we will be able to find it. Determining the slope of the land is difficult in the air, but often is easier for the firefighter on the ground.

Paramedics, EMTs, firefighters and law enforcement officers may not physically be in the helicopter with us, but they are a very valuable and important part of our team, and we count on them every time we fly to meet them on scene. They may see things that we can’t, and it’s what we don’t see that scares us.