Commercial, Safety

Let There Be Light

By By Terry Terrell | March 1, 2011

On the most recent last day of EMS helicopter creation, “Let There Be Light” was commanded, and a new and potentially constructive variety of light was introduced to the working helicopter environment in the form of night vision goggle (NVG) technology. Accordingly, our large metroplex-based EMS program has just concluded a comprehensive transition to NVG operations, and the training has revealed some interesting realities.

Peripheral considerations notwithstanding, the current quality of NVG technology is astonishing, especially when compared to early-generation night vision gear. We began with each of our pilots enjoying an introduction to contemporary NVG equipment and tactics, starting with a couple days devoted to FlightSafety’s excellent NVG simulation facilities in Tucson.

The latest light amplification equipment is, to earlier incarnations of “see in the dark” gear, as the iPad is to the Etch A Sketch, especially “in light” of our senior pilots having experienced “enhanced” night vision going all the way back to the original monocular Starlight scopes. The presently popular ANVIS 9 M949 night vision aviator’s goggles seem to be a supernaturally capable example of miracle technology, able to elevate virtually undetectable levels of ambient light to intensities which allow “photopic” ranges of optical function, and permit the user to identify wires, trees, terrain feature relief, lakes, rivers, ponds, grassy areas and even, at times, individual blades of grass. Additionally, late generation equipment is extremely fast and effective at attenuating bright sources of light that may appear in an otherwise dark field of view, rendering system performance completely interrupted in earlier generations. A user’s first look through Dash 9 equipment is nothing short of breathtaking, especially when contrasted against the same view with the goggles flipped up in the “unaided” position. Herein lies a subtle but potentially serious category of hazard, possibly more threateningly than ever before.


Most of us have studied accident histories that feature an element of distraction as a primary cause. Many will remember the Eastern Airlines Lockheed 1011 which tragically descended into the waters of the Everglades in 1972, wherein everyone on the flight deck became fatally mesmerized by the simple bulb failure of a nose gear “down and safe” indicator light. Then there’s the Tampa-based EMS BK-117 that struck an antenna wire in April 2000. No one survived that accident, and NTSB was forced to conclude that an experienced pilot flew into a highly visible obstruction located on a familiar route, on a clear VFR day, for “unknown reasons.” Their aircraft had recently seen installation of a new, visually impressive moving map display, and it has always been suspected that the veteran crew became distracted by the visually compelling new equipment.

As a potential distraction during night helicopter operations, NVG equipment can be many times more compelling than any moving map display. It can never be forgotten when using NVG equipment that all the usual items must be scanned and helicopter systems monitored. The upgraded outside visual data, and the limited “tunnel” field of view, balanced against all the peripheral visual and mental scanning normal to routine helicopter command, must be correctly and continuously prioritized in a dynamic way, so that NVG is used as a constructive tool. It must never become a distraction. Too much technology, introducing additional layering of physical and mental workload complexity, can be worse than not enough technology. Just ask victims of “texting while driving” auto accidents.

Dazzling though NVG technology may be, it cannot be considered a comprehensive “silver bullet” fix for EMS aviation safety weaknesses. Goggles can be an extraordinarily powerful tool. But in the end, this equipment is only one of many tools available to competent aviation professionals, able to take advantage of new capabilities when appropriate, but competent to resist being distracted by the temptation to fixate on a hypnotically inviting “light show”, no matter how spectacular. Goggles can certainly improve safety and comfort margins in many low-light environments, but statistics show that night obstacle and terrain strike hazards are dwarfed as a major killer in EMS helicopters by poor overall decision-making during mission execution.Especially when mission stresses are compounded by weather factors existing far outside sensory amplification function enabled by NVG technology.

“Let there be light” is unquestionably a milestone along the road to helicopter safety, but let’s make sure the enlightenment extends beyond the simple visible band, and into the composite scan that good situational awareness will always require.

Receive the latest rotorcraft news right to your inbox