The use of night vision imaging systems (NVIS) by civil helicopter operators is increasing significantly all over the world. North America has a leading role in terms of NVIS adoption. “In the United States, for example, very nearly all helicopter air ambulance (HAA) operators use night visions goggles (NVG) logging tens of thousands of NVIS flight hours each year,” says Kim Harris, director of business development at ASU. “However, NVIS HAA operations are becoming much more common also in Europe, the Middle East, Africa, and Asia,” he says.
REB Technologies Senior Vice President of Operations and Systems Jeff Stubbs also believes Eastern Europe, Asia, South America, and Africa are poised for big growth in civil NVG operations. “These regions are geographically very similar to the U.S. and Canada, in that the cities and towns are separated by a large expanse of countryside. We have also had significant success in Africa with the anti-poaching sector, with an instant drop off from poaching once NVIS aircraft are introduced. Although not a huge sector, it serves a vital need for the environment,” he says.
Beyond HAA
Traditionally, NVIS use in the civil aviation industry has been by HAA operators, but there are now several other applications of NVIS being witnessed. “Search and rescue (SAR) organizations depend on NVGs and enhanced vision systems (EVS) each night to successfully perform their missions and return safely,” says Harris. “In addition, NVG night firefighting enables crews to attack wildfires when those fires typically are at their weakest – at night when temperatures are reduced, humidity is often higher, and winds typically have decreased.” Other advantages to firefighting at night include the increased performance of both the aircraft and suppressant applied.
Stubbs believes that, like firefighting, aerial spraying operations will be another industry to start implementing NVGs. “The desire is there, the dangers are there and the increased additional safety is needed; they just need to secure the funding to implement and maintain an NVIS program, which is always a tough first step,” he says.
Barriers To Growth
According to Harris, budget is a barrier to growth in new markets as often organizations expect an NVIS program to be far more expensive than it needs to be. “There will be, of course, the additional cost of NVGs and crew training as well as the ongoing expense of inspecting and maintaining the aircraft and NVGs, but these costs are small and easily forecast,” he says.
Night Flight Concepts President Adam Aldous states that cost is a main barrier to NVG growth, and so are regulatory requirements (and lack of regulation) in some countries. U.S. State Department export limitations are also imposed for some regions.
Another main barrier is represented by education. “Certainly, some organizations that have not yet implemented an NVIS program view NVG flight with the perception that these operations are challenging and dangerous”, says Harris. “But modern civil NVG operations have easy access to state-of-the-art night vision products and the current NVIS cockpit modification technology and techniques are the product of literally decades of experience and improved materials performance.”
Safety Considerations
The main benefit of NVIS implementation is improved safety performance. “The proper use of NVGs has enhanced night safety for operators, specifically the ones tasked to perform flight duties into and out of scene landing sites,” says Aldous.
It should be noted, however, that operations with NVIS do not provide for alleviations in terms of lower minima for visibility, weather, altitude, crew day, etc. “NVGs are an added safety precaution that provides the pilot with additional situational awareness. From a safety standpoint it is also important to ensure that the equipment is functioning properly before takeoff, that NVGs are calibrated, that cockpit lighting is secure and operational, and that the aircraft is maintained and in good condition,” says Stubbs. “Moreover, training is also fundamental as night operations have always been a challenge; it is important to have proper training and maintain currency.”
Aldous says, “Properly maintaining the NVIS system should be top priority. This is driven by management, enforced by the unit managers, and practiced by the operators.” A well organized and comprehensive set of standard operating procedures should be implemented to set the organization’s framework; for example, the ‘left and right limits’ per se.
As part of NVIS adoption, a comprehensive implementation plan should be developed that includes aircraft modification as evaluated by a competent authority. “There are still people and organizations that think NVIS filtration is a simple matter of applying some NVG film to some of their equipment. NVIS aircraft modifications should always be performed to standards published by the FAA and EASA”, says Harris. “Those that do not do so will certainly experience incompatible light reflections during flight, usually in the most demanding conditions where the risk is greatest. Competent authorities that do not require NVIS supplemental type certificates (STC) but allow non-STC modifications that are not evaluated by inspectors trained in NVIS evaluations are accepting increased risk.”
Also, a good safety practice is to ensure that initial and recurrent training is conducted by instructors with significant civil NVG experience. “While there are a great number of well experienced military NVG instructors entering the civil market, their training is all based on tactical operations, the exact opposite of civil NVG flight operations. While military pilots bring valuable NVG experience, in my experience, they are never able to effectively teach proper use of aircraft searchlights and how those lights can more than double the effectiveness of NVGs”, says Harris. “They often think that infrared (IR) searchlights are a good NVG tool, when in fact they are a very poor tool, suitable only for tactical/covert operations that have no place in civil operations. They can damage the retinas of bystanders or first responders on the ground who look up at a landing helicopter.”
Selecting Equipment
NVIS implementation entails the selection of specific technologies and equipment. According to Stubbs, these need to be customized to the users’ operation, in terms of their mission, goal and capabilities. Then it is important to conduct an aircraft survey. Finally and maybe even more importantly, what is their normal process when an instrument or avionics use fails? Do they have a local facility to make the repair? Are they on a pay-by-the-hour maintenance program? Do they have to ship their units out of the country for repair/overhaul? “All of these factors should be taken into play when designing an NVIS solution to the aircraft,” he says.
NVIS technological solutions include internal and external modifications. With internal modifications, all of the instruments and avionics are internally modified for normal or NVIS operations.
External modifications are the most frequently used and include post-lights/eyebrow lights, bezels and filters. Post-lights/eyebrow lights are a traditional method to modify the crew station that predate NVGs. Bezels also predate NVGs and there are several different variations of bezels. The most frequent is a bezel that mounts to the face of the instrument with light emitting from the center to illuminate the instrument face. The full instrument bezel actually mounts to the instrument panel and fits around the instruments still illuminating the face. Filters are externally mounted and may be attached with aluminium bezels. Stubbs says, “All internal and external modifications are viable methods, but the operator must consider all the intricacies of its operation to make the best decision and ensure its aircraft are available for their intended mission in lieu of sitting in a hangar awaiting parts.”
Technological upgrades
From a technical standpoint, Jim Winkel, president of ASU, notes that L-3 and Harris manufactured NVGs have been recently TSO certified. “The FAA and these OEMs are finalizing a process, whereby NVGs currently operating via STC supplemental approval can be recovered to TSO. This will enable operators and inspectors to easily confirm that a Harris (formerly known as ITT and Exelis) or L-3 manufactured NVG – which has been recovered to TSO – is acceptable for flight with any approved NVIS STC or TC,” he says. “Additionally, operators who have invested in these approved, but older, NVGs will have an opportunity to upgrade to higher performance, without the cost of purchasing a new NVG.”
A significant step forward in NVIS technology is the constant and consistent improvement in the goggles. “It was not that long ago that the latest and greatest NVGs were 1,600 FOM (figure of merit) now that figure has moved to 2,400 FOM along with green and white phosphor. “The basis for the success of the NVIS cockpits of today is allowing the color displays, true color annunciators and maintaining the instruments true colors,” says Stubbs.
Looking ahead, it appears that NVG weight reduction is within reach. “Eventually a lighter and smaller digital system will be developed. There is also potential for a system that has multiple types of sensors incorporated, such as thermal, along with low-light image intensification. One other possibility is light amplification through biology, but this is pretty far off,” says Aldous.
With regard to weight reduction, ASU’s Kim Harris notes that the basic design and weight of NVGs have remained largely unchanged over the past 20 years and ASU will reveal a new lighter weight NVG design in late 2018.
Another important forecast upgrade, which would be primarily limited to the law enforcement sector, will be new dual-mode covert lighting capabilities that could be used with steerable searchlights, as well as landing and taxi lights. Stubbs says, “It is such a huge advancement from where we were as an industry just five years ago. We recently completed an STC in which the landing and taxi lights were 50 percent brighter than the original and less than half of the power requirement, and with the covert system the aircrew were able to easily identify terrain characteristics over 10nm away.”
As NVIS technology matures with a proven safety record, a hot-button issue that continues to remain has to do with how FAA NVIS STCs and TSO items are accepted by both TCCA and EASA. “As an industry, we are working with the various regulatory agencies and developing a dialogue specifically to work through these challenges,” concludes Harris.