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Friday, July 1, 2011

Police Mission Equipment

Next-generation avionics mission equipment in law enforcement aircraft provide enhanced communication and surveillance capabilities

By Ernie Stephens

Painting the words “police” or “sheriff” on the side of a helicopter does not a law enforcement helicopter make. It’s the mission equipment the search lights, radios, video systems, etc. that make it a police helicopter. Even in the 1960s and 70s, when police departments in the United States were first finding their wings but didn’t have access to the technology found on today’s aircraft, officers still understood that they needed more than their surplus military helicopters to adequately patrol their jurisdictions.

Tom Feddon was one of the first pilots to fly for the Metropolitan Police Department in Washington, D.C. He fondly recalls the early days of police aviation (circa 1970), when making their aircraft a useful platform took a bit of ingenuity and innovation.

“The Bell-47 [similar to the aircraft made famous in the 1970s TV series M*A*S*H] was our first helicopter, but it only had aviation radios,” recalled Feddon, who retired as the agency’s chief pilot in 1991. “So, we mounted a motorcycle radio on some isolation mounts on the tail boom, ran a control head up to the front, and that’s what we were using for police radios.

“There were no gyro-stabilized binoculars, so we used regular binoculars,” said Feddon. “But those didn’t work very well. If you tried to look through them in a turn, they made you sick. We had to pull into a hover to make it easier.”

Feddon said search lights came onboard a few years later, but that was about as far as police avionics went during the city’s Bell-47 days. Better radios and search lights would come in the 1980s, when the department upgraded to turbine aircraft.

Complex police mission equipment is no longer an afterthought, though. The gear that goes aboard patrol aircraft is just as important and often just as expensive as the aircraft itself. Just ask Matt Murphey, who serves with the Aircraft Section of the Texas Department of Public Safety (DPS).

“Our 2008 aircraft was $1.5 million, and we spent another $1.5 million on equipment,” said Murphey, whose job it is to select equipment for the agency’s 15 American Eurocopter helicopters and eight Cessna airplanes. “It included the EFIS [electronic flight instrument system], the thermal imaging camera, the mapping system, six police radios, two aviation radios, navcoms, satellite phones that kind of stuff.

“The most popular piece of police equipment we use is the moving map system,” said Murphey. “For the officer to be able to pick out an address in a big city or a small town is invaluable. And with all of the wildfires that we’ve had, the aerial mapping feature has gotten really popular with the emergency management folks.”

Equipping the Fleet

The Maryland State Police (MSP) in October 2010 ordered four new Agusta Westland AW139 medium twin-engine helicopters. They are the first wave in what is hoped to be a total order of 11 ships to replace the department’s aging fleet of 10 Eurocopter AS365 Dauphins, which first entered service with the aviation command in the late 1980s.

Bill Bernard, the director of flight operations, and a retired MSP lieutenant and pilot in his own right, is working on the AW139 acquisition program. This includes the selection of equipment that will serve all three aspects of the command’s mission law enforcement, homeland security, damage assessment, emergency medical transport and search and rescue.

“It isn’t that we’re unhappy with the Dauphins we’re currently flying, because they served us exceptionally well,” Bernard said. “But due to the age of the fleet, it was time to initiate a process for a state-of-the-art aircraft to serve the citizens of Maryland for the next 20 years.”

Different, in this case, will include upgrades and equipment never before sported aboard an MSP helicopter.

Police Radios: A law enforcement helicopter is useless if its crew doesn’t have a way to relay its observations directly to ground units. This can be particularly complicated in MSP’s case, considering law enforcement agencies in Maryland operate in frequencies ranging from 30 MHz to 960 MHz. Each aircraft must also allow crew members to use and control radios independently from any position in the aircraft, without affecting any other crew member.

To fulfill its communication needs, MSP has selected a suite of Wulfsberg RT5000, P25-compliant, digital transceivers from Prescott, Ariz.-based Cobham Aerospace Communications. They will be coupled to two control heads on the flight deck, plus four more mounted in the aft cabin, allowing trooper-paramedics to talk to an array of ground-based officers, emergency medical technicians and trauma center personnel.

Forward-Looking Infrared (FLIR) Video Camera: Mounted just under the nose in a ball turret, the combination FLIR and color video system is considered by most airborne law enforcement personnel as one of the most important pieces of patrol gear aboard the helicopter. The FLIR system creates a black and white image from an object’s heat signature, and displays it on a computer monitor for the flight crew. In total darkness, the system is able to “see” nearly everything, from people to freshly ejected bullet casings. The color camera, which shares the same housing as the FLIR sensor, is similar to a professional-quality video camera. Both are often connected to a video cassette or digital recorder in the cockpit.

MSP selected the Wescam MX-15i from L3 Communications’ Wescam division in Burlington, Ontario, for this duty. The department will tie it into a digital video recorder.

Searchlight: A high-powered searchlight is a staple aboard all police helicopters. Its primary purpose is to illuminate crime scenes and search areas from above. In a medevac role, the pilot uses it to check landing zones for obstructions prior to making final approaches into unimproved areas.

Bernard and his team selected the 40-million candlepower SX-16 Nightsun, with an in-flight infrared change-over (IFCO) feature, from Sylmar, Calif.-based Spectolab. (An IFCO flips a filter over the lens to block out the beam’s white light, allowing passage of only that portion of the light spectrum needed by night vision equipment.) The entire searchlight system can be operated independently, or slaved to “look” wherever the MX-15i FLIR-video system is aimed.

Moving Map: Although Maryland is the eighth smallest state in the United States, finding precise locations as quickly as possible is still extremely important to an aircrew. Therefore, a moving map system is paramount to its ability to function effectively inside of the state’s boundaries, as well as in neighboring states, where they are often called upon under a decades-old mutual aid agreement. The best piece of mission equipment to help crews get around is a moving map system loaded with detailed street and property information, as well as time, track and heading data to any given destination.

EuroAvionics, based in Pforzheim, Germany, has been tapped to provide Maryland State Police with the Euronav moving map system. Its multi-color display can give detailed street information down to individual addresses, as well as use internally generated aviation navigation chart overlays that show the aircraft’s position in the national airspace system.

Digital Video Downlink: “A picture is worth a thousand words” is an old saying that also applies to airborne law enforcement, which is why many police helicopters equipped with FLIR-video systems utilize digital downlink transmitters to beam what they are looking at to ground units, much like a television news chopper sends live views of the morning rush hour to the station. From a police perspective, ground commanders equipped with receivers can get a birds-eye view of a crime scene, hostage situation or the aftermath of a disaster in real time.

Microwave Radio Communications, based in North Billerica, Mass., will provide its MRC Strata, 625 MHz, digitally encrypted downlink system, mated with an omni-directional antenna. Portable ground receivers for forward-deployed command personnel are included in the deal.

Night Vision Goggles: The National Transportation Safety Board has released a series of recommendations calling for the routine use of night vision goggles (NVG) aboard helicopters used for emergency medical transports. Many of the law enforcement agencies that provide medevac services are accepting that recommendation, and are equipping their crews with NVGs to aid them in spotting obstacles and terrain at nighttime. In addition to the goggles and the helmet mounts they attach to, the aircraft itself needs to be NVG compatible to help keep standard instrument and interior lights from interfering with the goggles’ ability to process images.

MSP currently uses ANVIS-9 NVGs in a limited way, but will soon train-up all flight crew members to be proficient in their use. The AW139’s cockpit and exterior lights will be NVG compatible, but many of the lights used by the trooper-paramedics in the aft cabin to tend to patients will not be. To protect the pilots, a blackout curtain separating the two sections of the aircraft will shield the flight deck from the bright lights.

Ernie Stephens is the editor at large for Avionics sister magazine Rotor & Wing.

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