Bristol Industrial & Research Associates Ltd (Biral) specialises in the design, manufacture and global distribution of high-quality sensors for the meteorological professional market. Biral manufacturers the VPF and SWS range of Visibility and Present Weather sensors as well as the unique BTD-300 Thunderstorm Detector, which are used in the most demanding applications such as aviation, offshore platforms and wind energy.

Meteorological sensors for aviation ground use

With air traffic volumes set to increase year on year, airport operators are under increasing pressure to expand services while maintaining or improving safety and customer satisfaction. Many of the challenges this brings can be addressed by careful planning, adopting best practice and investment in new infrastructure and technology. However, the weather will always remain outside of our control with an ability to cause major disruption. Accepting that we cannot control the weather, having accurate information about current conditions is vital for allowing operations to continue with minimum disruption, while ensuring that safety is never compromised. Meteorological sensors therefore should be seen as an important part of any airport, whether it is a simple grass strip or a major international hub.

All Biral sensors for use in aviation systems, including RVR, meet or exceed the requirements of ICAO (ICAO 9837 and ICAO Annex 3), WMO, FAA, CAA (CAP437, CAP670 and CAP746) and CAAC. Calibration is in accordance with ICAO 9328 and is traceable to a reference standard transmissometer.

Visibility measurement for runway visual range (RVR) and METAR

Knowledge of visibility along the runway is of vital importance to pilots during landing and take-off, which is why the estimation of Runway Visual Range or RVR is perhaps the most common use for visibility sensors in aviation. Visibility is also an integral part of MTAR and SPECI reports provided by airports as part of their air traffic management responsibilities. In larger airports visibility measurement on taxi ways is increasingly used to improve the safety of ground movements.

Present weather sensors and measurement

The term present weather is used to describe the current conditions, which might include anything from tornados to blizzards. When applied to a sensor the term covers a more limited set of conditions, which generally include visibility, and liquid and frozen precipitation. In aviation, present weather sensors provide information for the formulation of METAR and SPECI reports as well as airfield and regional forecasts.

Forward scatter present weather sensors can struggle to distinguish between liquid and frozen precipitation, an important capability in aviation where icing on aircraft and runways is a serious safety concern. Biral sensors are the only sensors to reliably solve this problem by using a backscatter receiver.

Ambient light sensor for RVR

When calculating RVR three pieces of information are required: visibility, ambient light level and runway light intensity. While runway light intensity is often directly available to an integrated control system, visibility and ambient light levels must be measured at the runway. The ALS-2 Ambient Light Sensor connects directly to VPF or SWS sensors, providing visibility and ambient light measurements in a single data message.

Thunderstorm (lightning) detection

Airport managers have a duty of care towards their staff, to protect them from the dangers associated with lightning activity. Often operating in open spaces and handling volatile liquids or expensive machinery, these workers are normally some distance from any safe areas. Key airside operations like baggage handling and aircraft refuelling, for example, need time to make their operations safe. The ability of Biral’s BTD to provide a warning of the threat of lightning activity in the immediate area provides operations managers with the time needed to assess the risks and initiate the appropriate actions to mitigate them.

The BTD Thunderstorm Detector is a standalone sensor that reliably detects the presence of all forms of lightning to a range of 83km, exceeding the requirements as described by the Federal Aviation Administration (FAA). The unique quasi-electrostatic operating principle gives the detector a very low false alarm rate and the ability to warn of the risk of overhead lightning. Highly immune to radio interference – the major cause of false alarms in traditional standalone detectors – the BTD is able to detect charged precipitation, cloud-to-ground and as well as weaker but more common cloud-to-cloud lightning.

Application support

Formed in 1975, Biral has a rich history in designing and making innovative products. We appreciate that every application is different and can present questions that are new to our customers; for this reason our meteorological products manager and our team of product development engineers are available to discuss any technical questions you may have with your equipment or application.

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