NASA Tech Briefs: How does the TAMDAR project serve the mission of NASA's Aviation Safety Program?
Taumi Daniels: The small component of NASA’s overall Aviation Safety Program that funded the TAMDAR project has a particular interest in improving aviation weather information for pilots. Statistics show that weather is a contributing cause to 30% of all aviation accidents. To tackle this problem, we realized that we had to provide pilots with better weather information. If you go back about six years and look at the type of information that was available for pilots, you realize that the weather information that was being provided had to be improved. To accomplish this task more weather data has to be collected. That data can be used to create improved weather products, which in turn can be data-linked back into the cockpits so that pilots can make better-informed decisions with respect to weather.
NTB: How are weather conditions currently measured?
Daniels: Prior to TAMDAR – and still in use today – you had four sources of upper-air measurements: (1) next-generation radar, such as the system that was deployed in 1988 called the wind shear radar system (WSR88 NEXRAD), which are deployed all across the U.S. and provide moisture and wind measurements; (2) wind profilers – microwave radiometer radars that are mounted on the ground, point straight up, and measure the wind fields – that are deployed mainly across the Great Plains; (3) weather balloons that are launched twice a day from 70 locations across the U.S.; and (4) satellites that measure temperature, irradiances, and cloud cover, as well as extract moisture and icing information. In addition to these sources, the big airliners provide temperature and wind data called MDCRS (meteorological data collection reporting system). All of this data is ingested into the forecast models on an hourly basis. The National Weather Service does a fantastic job with ingesting all of this data, outputting all of the models, and providing forecasts; however, if you look at the huge amount of data – where it is collected, how often it is collected – you see gaps. This is where TAMDAR comes in.
NTB: How is TAMDAR different?
Daniels: First, the instrument measures temperature, humidity, pressure, winds icing, and turbulence, which is time and location stamped using GPS (Global Positioning System) technology. All of this information forms an observation that is then automatically sent to the ground in the form of an automated PIREP (PIlot REPort – a voice report from a pilot on current weather conditions). The NSF sponsored an aviation weather task force in 1986 and one of the highest priorities was the development of an automated PIREP system. There isn’t necessarily a lack of these reports, but they are subjective. So, an objective, automated measurement of the weather was needed. This is the purpose of TAMDAR; it is an automated system.
NTB: How was the sensor tested?
Daniels: To begin with, if you look at all of the little airports where the regional airliners fly – in particular the company (AirDAT) contracted by NASA to develop the sensor that partnered with Mesaba Airlines (a Northwest Airlink affiliate headquartered in Minneapolis, MN) – they are in locations where there is no weather balloon launch or NEXRAD radar system; so, this information is not being collected in these locations. Every time a Mesaba airplane takes off or lands you get a “sounding.” A sounding is all of that weather data mentioned earlier that is measured at each altitude as the aircraft flies up or down. With a sounding, a meteorologist at any of the local offices then knows what the structure of the atmosphere is and can therefore make a very good forecast of, for example, precipitation type, or the onset of fog or snow.
So there are two uses for the collected weather data: feed it into the huge computer forecast models and give it to the local forecasters. This is what we did in the Great Lakes Fleet Experiment, this is a big, yearlong experiment that we conducted starting in January of 2004 and just ended a couple of weeks ago. The objective of the experiment was to determine the impact of airborne observations on numerical models and on the local forecasts. This was a really big experiment with a whole bunch of researchers from around the country working on it together. I thought of it as kind of like the Linux Open Source model – provide the data for free and then see who is willing to use it.
In addition, we wanted to see the impact of this data on some of the product development teams. The FAA has a program called the aviation weather research program, which is composed of 10-12 product development teams (PDT). Each of these teams is composed of researchers scattered across the country who are trying to improve weather products that will then eventually be used by pilots, weather briefers, and others in aviation-weather community. In particular, there is the turbulence PDT, the icing PDT, the convection PDT, a team that is trying to improve the NEXRAD radar, and several others. Four of them – the icing, turbulence, surface temperature, and convection PDTs – are currently evaluating the use of TAMDAR data and the impact of the data on their particular weather product. While the experiment is completed, I am still waiting for final results from these different groups.
NTB: Will the TAMDAR sensors be utilized on commercial aircraft?
Daniels: Originally, the TAMDAR was intended for the GA (general aviation) community – the small airplanes. When we first thought of the idea for the TAMDAR we thought that these are the aircraft that have the most accidents, so these were the pilots that we had to help the most; however, the business model simply was not there. You are not going to be able to ask someone who flies the little airplanes to pay for a $4,000-$5,000 sensor and report all this weather data that is not necessarily going to help them immediately. We had a business feasibility study done, and in that study they pointed out the obvious fact that the sensor should be installed on regional airliners – the turbo prop planes and the smaller jets. This is why when we finished the sensor development we partnered with Mesaba.
AirDAT’s new business model includes providing the weather data for free and they are using the information to develop their own weather products. The company did announce in December that they partnered with Horizon Airlines. They are continuing to equip more airplanes across the U.S. and collect more of this data. It is nice to know that this is actually going to result in something long term.