The NTSB recently made a startling (to it) discovery that there is latency involved with the Nexrad pictures that pilots are looking at as they try to avoid weather. To read the NTSB Safety Alert on the subject, you get the feeling that they just crawled out of a hole and discovered weather in the cockpit.
A quote from the NTSB Safety Alert in relation to the coverage of this: “…the NTSB has not found that such guidance contains details about the potential time difference between the age indicator and actual conditions.” They seem to think pilots have not been told that the age of the picture shown on the screen is just that and is not the age of the weather information used to generate the image. That is an insult to those of us who inform and educate pilots.
A quote from the April, 2003, issue of FLYING: I said when writing about the new Nexrad displays from Bendix/King and Garmin that, “Both systems have a way of identifying the age of the product that you see. The ages on metars and forecasts and pireps are an absolute. The Nexrad picture displayed by both systems does have an age in minutes shown on it but nobody has been able to come up with how the age relates to the time since the radar sweep actually examined a piece of weather. Maybe there is no specific answer to that question. It could be something like from 10 to 20 minutes.”
Now, over nine years later, in discovering this, the NTSB, in the Safety Alert and in bright red bold type, says it could be from 15 to 20 minutes.
It was a while ago, but I remember that the people I talked to about this would not put a definite time on it because there are too many variables. It was the consensus that 10 to 20 minutes would be adequate to alert users to the fact that the information is far from brand new.
I have written many times since about Nexrad and I have always stressed that the age of the information is a factor in using Nexrad. I have explained that old-timers still prefer radar in the airplane for that very reason. Mac McClellan has written about this a lot, too.
I have also covered this in Air Facts videos for Sporty’s and have shown how the presentation of precipitation lags behind the development of a cumulus in real time.
But, alas, nobody has any sense but the NTSB. It took a lot of smarts for it to learn in only nine years what the rest of us learned at the beginning of the Nexrad program. In the Safety Alert, the NTSB cited two accidents where this was probably a factor. In truth there have been many such accidents and they will likely continue.
Sure, pilots will misuse Nexrad information. In truth, it is useful mainly in avoiding areas of weather. It does not work for the penetration of an area of weather and this has been repeatedly stressed.
For years I had Nexrad plus one of the latest airborne weather radar systems in my airplane. I had never enjoyed poking through a system, trying to avoid individual cells with radar. After I got Nexrad, I didn’t have to do that because I’d fly a lot of quality miles to stay the hell away from all the cells, as indicate d on Nexrad.
What has been your experience with this and do you think pilots look at Nexrad pictures through rose-colored glasses? Do you think he NTSB is out of touch?
For over 50 years, pilots turned to Richard L. Collins for his unique perspective on the challenges and rewards of flying light aircraft. He started his career working with his father, Leighton Collins, at the original Air Facts magazine. He then went on to work for the leading aviation magazines, including as editor of both AOPA Pilot and Flying. With over 20,000 hours of real world experience, much of it in Cessna 172s and P210s, Collins wrote about safety, weather and air traffic control from first-hand experience. He was the author of numerous books, including Logbooks, published in 2016 by Sporty’s Pilot Shop. Collins passed away in April, 2018.