Reliable Weather and Visibility Sensors Protect Airports in Winter Weather Events

April 18, 2023
The Grimsey Airport in Iceland relies on Vaisala forward scatter technology to help airport decision-makers maintain safe operations by accurately identifying and reporting on challenging visibility and harsh weather conditions.
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With rain, snow, ice, heavy winds and air-driven salty rain, Grímsey Island experiences some of the most challenging weather in Europe.  

Having reliable visibility and weather sensors are important for all airport operations, but especially for those who face extreme weather conditions regularly. Measuring and reporting visibility at airports helps optimize operations by determining what procedures and routines aircraft need to take off and land safely.  

“The salt is highly corrosive and can negatively impact measurement instruments, while the harsh weather conditions and low visibility create airport operation concerns,” said Isavia Project Manager Hólmgeir Þorsteinsson. “Since small aircraft primarily use the airport to transport supplies and services, precise weather information and visibility detection are crucial to making accurate decisions that maximize uptime.” 

In September 2022, the airport decided to replace the existing sensor, which was more than five years old and was experiencing problems due to the harsh environment.  

Prior to selecting a new system, the airport had to consider the harsh environment and difficult-to-reach remote location, the importance of reliable, accurate weather information and the necessity to minimize travel for maintenance personnel.  

“Compounding the problem, since only two flights arrive at Grímsey Airport each week, the cost of sending maintenance staff to the island to repair the sensor is prohibitive,” Þorsteinsson said. “Considering lifetime operational costs versus ongoing maintenance, upgrading to the Vaisala FD70 emerged as the more cost-efficient option.” 

Vaisala FD70 

“FD70 is a forward scatter sensor, which analyzes scattered infrared light from the sample volume. FD70 utilizes the latest leading technology from Vaisala,” said Nordics Vaisala Sales Manager Veera Skyttä. “The novel combination of a homogenous single thin light sheet with a light receiver under the optimal forward scatter angle of 42° and the fast signal sampling and high-resolution signal conversion sets a new standard in visibility and present weather determination accuracy. Together with accurate temperature and humidity measurements, the FD70 defines the parameters from the light measurements.” 

The forward scatter technology solution delivers enhanced measurement stability without ongoing maintenance and helps increase operational uptime at an airport where weather-related downtime is untenable.  

“In addition to the visibility reporting, the FD70 gives the present weather code, or the cause of reduced visibility,” Skyttä said. “The most challenging and, at times, the most important precipitation types for operational decision-making are freezing rain and freezing drizzle. These supercooled liquid precipitation types have traditionally challenged forward scatter sensors, but the FD70’s patented light sheet technology, use of external humidity and temperature sensor and second receiver takes the instrument's performance to the maximum and eliminates guesswork.” 

Improving the future of airport operations 

According to Vaisala, the remote island of Grímsey has about 60 residents plus visitors who rely on the island’s airport for transportation as well as supplies and services. 

“FD70 enhances the reliability of the visibility and present weather reporting, thus replacing the need for on-site human observations or METAR reports,” Skyttä said. “The measurement technology, design and powerful signal analysis protect the FD70’s measurement capabilities against various unwanted operational disturbances.” 

Vaisala said to the downward-looking geometry, the FD70 is not vulnerable to direct sunlight or spider webs.  

“The unique particle type differentiation in FD70 enables the identification and separation of flying insects from precipitation particles, minimizing the need for maintenance and on-site visits,” Skyttä said. “FD70 has advanced self-diagnostics that indicate beforehand when to schedule the next maintenance visit.” 

Remote FD70 monitoring can be done via Ethernet from central locations eliminating the need to send personnel out in harsh weather environments. 

“Additionally, the modular design enables very short and easy repairs, thus allowing airport maintenance staff to work efficiently and effectively — without specific device know-how,” Skyttä said. “The Norlandair flies from Akureyri to Grimsey only two times a week, which means one week of travel for maintenance personnel from Reykjavik every time the sensors need attention. With FD70, the need for maintenance is minimized since the system can be diagnosed remotely and possibly by local staff.” 

Þorsteinsson said since installing FD70, the airport never has to miss a weather event and can prioritize optimal airport operations without worrying about maintaining the sensor.  

“Together, the solution’s robust design, downward-looking geometry, heated window and unique compensation algorithm empower airport operators like us with year-round confidence,” Þorsteinsson said.