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Advances in Helicopter SAR Tech Push Against the Impossible

Posted 1 years 19 days ago ago by jhadmin

There are some helicopter search and rescue (SAR) missions that are just impossible.

A prime example of this was the crash of a Dehavilland DHC-2 ‘Beaver’ on Alaska’s Thunder Mountain on 4 August 2018. Flown by Rust’s Flying Service, the sightseeing plane had one pilot and four tourists onboard when it accidentally turned into a high-hanging glacier in Denali National Park.

At 18:00 hours, the pilot managed to get a satellite call to Rust’s Flying Service; asking for help before contact was lost. After many reconnection attempts, the pilot was reached once more. He reported being trapped in the wreckage with two possible fatalities onboard. Then contact was lost.

The National Park Service (NPS) dispatched its AS-350 B3e high-altitude rescue helicopter from its base in Talkeetna to the crash location reported by the Beaver’s emergency transmitter. “We had no ability to get to the site at that time, since snowy, windy weather had settled onto the mountain,” said Nic Strohmeyer, an NPS aviation helicopter specialist. “So our SAR helicopter had to return to base.”

On August 6, when the weather cleared somewhat, the NPS B3e returned to Thunder Mountain to look for the crash site. They found it; the site was treacherous: The Beaver was broken in pieces and lodged in a crevasse at 10,920 feet hanging nearly vertically from the incredibly steep mountainside.

Despite the danger of the situation, NPS mountain rescue ranger Chris Erickson got onto a ‘short-haul line’ that was suspended below the B3e, and flew right up to the crash site. (Survivors were not expected to be found at this point, but the NPS had to be sure.) He spent five minutes there confirming that no one had survived, before worsening weather forced the B3e to retreat.

Four days later, pilot Hermansky kept the B3e hovering over the crash site for 50 minutes, while NPS rescue ranger Tucker Chenoweth hung from a 200-foot short-haul line and checked the wreckage in detail. Unfortunately, the conditions were just too dangerous to recover the bodies or to remove the aircraft debris from the mountainside. They remain there to this day; having since been buried by an overhead ice collapse.

Pilot Andreas Hermansky’s SAR flying skills during this mission, were recognized by the Helicopter Association International (HAI) Salute to Excellence Appareo Pilot of the Year Award, during HAI Heli-Expo 2019.

A Hunger for Technological Solutions

It may seem strange to start a story about advances in helicopter SAR technology with the tale of this unsuccessful SAR mission. Yet, the fact that this rescue could even be attempted speaks to the advanced state of helicopter SAR technology today -- and the commitment by the NPS and other SAR operators to make other seemingly impossible missions possible through the use of advanced technology.

At the NPS, they’ve been pushing the boundaries of helicopter SAR by deploying remote-controlled drones, like the 3DR Solo, to provide enhanced reconnaissance capabilities to SAR crews. “The drones allow us to peek over ledges and other obstacles in the Grand Canyon without having to deploy helicopters with people on board,” said Strohmeyer. “However, high altitude, short battery life, and sub-freezing temperatures make drones incompatible for mountain rescue operations in Denali.”

The U.S. Coast Guard is using night vision goggles (NVGs), enhanced EO/IR video cameras, and evaluating unmanned aircraft system technology to enhance their helicopter SAR capabilities. In addition, the Coast Guard is exploring the adoption of two additional sensing technologies on its Sikorsky MH-60 Jayhawk and Eurocopter MH-65 SAR helicopters. These technologies are Visual Detecting and Ranging (ViDAR) and Light Detection and Ranging (LIDAR).

As the name suggests, ViDAR is suited for daytime searches when visible light is available. Made by Sentient Vision Systems, ViDAR is designed to serve as an “optical radar system,” by using a “single or multiple nine-megapixel secondary sensor(s) and onboard automation software designed to automatically detect objects on the ocean in real time,” states the company’s web site at www.sentientvision.com. “The nine megapixel sensors operate akin to an airborne radar, but in the visual domain, by sending objects detected to the operator for further analysis by the aircraft’s primary sensor,” the website continues to state. The ViDAR equipment is built into an external pod, which can be mounted on various points on a SAR helicopter and integrated with its onboard sensor suite.

In contrast, LIDAR “is a remote sensing method that uses light in the form of a pulsed laser to measure ranges (variable distances) to the Earth,” states the National Oceanic and Atmospheric Administration (NOAA) web site at oceanservice.noaa.gov., which continues to explain, “These light pulses – combined with other data recorded by the airborne system – generate precise, three-dimensional information about the shape of the Earth and its surface characteristics.” This makes LIDAR a very useful tool for nighttime SAR missions.

“ViDAR may provide a tremendous enhancement to visible light searches,” said Scott Craig, Air Domain Lead with the U.S. Coast Guard’s Office of RDT&E (CG-926)/Acquisition Directorate. “Using the EO/IR is like viewing the ocean through a straw; your field of view is extremely small. Likewise, small objects are difficult to pick out on the ocean’s surface using just your eyes. ViDAR can take in the entire scene—like radar does—and can potentially spot a distinct object like a floating person from a mile away. You can spot a mariner much better using ViDAR than a human eyeball can.” To minimize false positives, ViDAR's search data is filtered by the system’s software, with meaningful results being displayed to SAR technicians in the helicopter.

As a detection technology, ViDAR appears superior to LIDAR in daylight conditions in terms of actionable information it provides to SAR operators. This is why the Coast Guard is interested in advancements to expand ViDAR’s application in low-light conditions. Still, LIDAR could be a useful supplement to nighttime searches over water, and the cruder image returns provided by conventional airborne radar. As a result, ViDAR and LIDAR could find their way into Coast Guard SAR helicopters in the foreseeable future.

In addition to ViDAR and LIDAR, the Coast Guard relies on surface search radar on its rotary- and fixed-wing SAR aircraft, plus cutting-edge cockpit automation. “Improvements in onboard automation and the introduction of glass cockpits reduce crew workload and improve situational awareness,” said Craig. “This helps the air crew focus their attention on the search in progress, rather than running the aircraft.”

It’s worth noting that  not every U.S. government service is in a position to make technological updates. For instance, "From what other pilots have said, Navy SAR hasn't changed much over the years’,” wrote Lt. Travis Callaghan, media officer with the Commander of Naval Air Forces. He  relayed information sent to him by the point of contact (POC) at Naval Air Forces Pacific: “The MH-60S has Breeze-Eastern or Lucas rescue hoist capable of hoisting 600 pounds. We use standard SAR loadouts of rescue litter and rescue strop. The MH-60R is very similar; they provide organic SAR to independent deploying ships as the only aircraft embarked."

Helicopter SAR Product Advances

Advances in helicopter SAR technology can’t happen without the efforts of the companies who make this equipment. Rotorcraft Pro contacted a number of them, to find out what new offerings they have:

Becker Avionics’ advanced MR510 Personal Locator Beacon improves the chances of rescue for anyone carrying this multipurpose survival radio and locator device. About the size of a conventional mobile radio, the MR510 comes complete with a transceiver, VHF/UHF/C-S antennas, and latest generation 12-channel GPS all in a rugged, waterproof package.

Whether manually activated or automatically switched on by lanyard or water immersion, the MR510 sends out distress signals on the international VHF/UHF emergency frequencies and to COSPAS-SARSAT (CIS) satellites. It tells rescuers where the MR510 user is located, and allows this person to speak with them via the MR510's two-way VHF/UHF simplex radio. The MR510's lithium battery will run for more than 24 hours guaranteed, in temperatures ranging from -40°F/-40°C to 131°F/55°C and in water depths down to 10 meters.

Boeing’s Spectrolab is known for providing a range of searchlights for helicopter SAR. At HAI Heli-Expo 2019, Spectrolab introduced two MIL-SPEC products for this market. These are the Nightsun XPM and the Search Landing Light (SLL) 46-200.

The Nightsun XPM is a 1,600-watt searchlight (using a Xenon gas arc lamp) for visible light operations, supplemented by an LED-based IR light array for non-visible light SAR operations. The Nightsun XPM features instant-on lamp ignition, the ability to switch from visible to IR illumination at the flick of a switch, and the ability to integrate with a helicopter’s onboard EO/IR sensors and moving map systems. “It is able to illuminate areas up to a mile away,” said Luis A. Castro, Spectrolab’s business development manager for Illumination and Sensor Products.

The SLL 46-200 is a high intensity Par-46 helicopter landing light (250,000 peak candela) that can be used in either visible light or IR modes. It is a steerable LED light whose azimuth and elevation can be controlled from the flight deck and it has the robustness to be deployable at air speeds up to 200 knots. 

“This higher-than-usual air speed rating allows the SLL 46-200 to be deployed at higher altitudes than most other landing lights,” said Castro. “Its range is about 250 feet, which makes it useful in aerial searches as well as landings.” The SLL 46-200 is designed to be a Par-46 drop-in replacement for many stock helicopter landing lights.

Breeze-Eastern is known for its helicopter rescue hoist systems, which are available in AC, DC and hydraulically powered versions. “These hoists are rated and capable of lifting between 300 to 600 pounds utilizing the best operating safety system in the industry—a reactive overload clutch,” said Mike Koons, Breeze-Eastern’s director of sales.

Asked about helicopter SAR equipment advances, Koons replied, “the industry’s increased mission requirements have resulted in the demand for new and improved tools to accomplish these missions.” In response, Breeze-Eastern has designed new cable technology that “will ultimately eliminate common operational issues with the cable,” he said. “We have seen improved durability, strength, and improved rebound characteristics, all of which will result in less cable replacements. We have also designed a lighted bumper that is easily installed above the rescue hoist hook.”

Koons added, “For Breeze-Eastern, above all else, except for safety, product reliability is critical. To that end, we have improved our motors by developing a new DC brushless motor. Coupled with the new improved cable, this will vastly reduce the seemingly increasing frontline maintenance; thus reducing the overall lifecycle and direct maintenance costs of the rescue hoist system.”

Switlik manufactures the X-Back MOLLE constant wear helicopter life vest. The X-Back MOLLE is designed to reduce bulk and weight around the neck, while decreasing fatigue and reducing interference with helmets. 

Switlik also makes the U-Zip-It Anti-Exposure Dry Suit. Originally developed for U.S. Coast Guard helicopter crews, the U-Zip-It uses a unique U-shaped zipper path to make it easier to put this dry suit on and off. Switlik makes large inflatables like the MRP-10 Marine Rescue Platform as well, which can provide immediate flotation to ten or more people.

“We were the first–and remain the only–to offer the X-Back design, which in itself is an innovation in constant wear life vests,” said Sarah Switlik, the company’s VP of Sales and Marketing “I believe we were the first to offer the MOLLE panels on life vests, and we remain the most customizable vest available on the market.”

“After many years of no innovation in dry-suit designs, Switlik was the first, and remains the only, to offer our U-shaped zipper,” she added. “We recently developed an advanced zip-in/zip-out summer and winter weight liner system. This allows users to fully adjust the amount of thermal protection they need in the suit as their mission parameters change.”

As for the MRP-10? “I don’t believe there is another product like it on the market,” said Switlik. “We recently introduced the first-of-its-kind, 5-year service interval (nobody else offers that) with a go/no-go pressure gauge; allowing users the ability to perform quick and easy safety checks to ensure the raft is charged and ready to fire.”

Pushing Back the Impossible

The SAR equipment advances listed above, combined with advances in helicopter technology, are making possible rotary-wing SAR missions that were unthinkable just years ago. One day, these advances will likely progress so far that even currently-impossible rescues like that Thunder Bay crash may become possible.

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