NTSB issues safety alert on limitations of cockpit weather displays

WASHINGTON, D.C. — The National Transportation Safety Board (NTSB) has issued a Safety Alert to warn pilots using in-cockpit FIS-B and Satellite Weather display systems that the NEXRAD “age indicator” can be misleading.

The actual NEXRAD data can be as much as 20 minutes older than the age indication on the display in the cockpit. If misinterpreted, this difference in time can present potentially serious safety hazards to aircraft operating in the vicinity of fast-moving and quickly developing weather systems, NTSB officials said.

NEXRAD mosaic imagery depicts weather conditions from multiple ground radar sites. The NEXRAD “age-indicator” on the cockpit display indicates the time that the mosaic image was created, not the time of the actual weather conditions. The NEXRAD image is always older than the actual weather conditions.

The NTSB has cited two fatal weather-related aircraft accidents in which NEXRAD images were displayed to the pilot that were presented as one-minute old on the age-indicator, but contained information that was up to five to eight minutes behind the real-time conditions.

The Safety Alert also reminds pilots of the importance of obtaining a thorough preflight weather briefing.



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  1. KK says

    Just about every pilot I know that uses NEXRAD already knows about the time delay on their displays. It was greatly elaborated on on AOPA’s online training course (basic knowledge, not actual certified training BTW) for using NEXRAD.
    The knowledge has been around for quiet some time and it’s the same thing with other sources of whether info, save for on-board radar and stormscope.

    And only now does the NTSB make an AD of this practical knowledge? 
    *shakes head*Boy are they behind.

    • GTWout says

       I don’t think you actually read it.  They aren’t talking about a time delay, they are talking about the fact that the time given on the display doesn’t correspond to the actual time of the wx, and it can be a significant amount of time difference.  What AOPA training discussed this?

  2. racer46 says

    I have encountered many times when the cells are not exactly where depicted in the latest display of Nexrad.. In daylight ,your eyes are still reliable when  you need to stay out of trouble. Nexrad is good, but on-board radar and stormscope is more accurate. When you don’t have either,and are using Nexrad, be sure to stay farther away from the depicted weather than you would with on-board radar  Nexrad is much better than no system at all.  

  3. Funnyfeelintoo says

    Now,,,let me understand all of this. FAA warning us about XM weather being up to 8 minutes old but “reminds pilots to of the importance of obtaining a thorough preflight weather briefing” that information would be 30 minutes to an hour old????? I’l take my XM weather data any day. I love it.

  4. Flye2242 says

    This is why in weather situations I also use my radar and storm scope.  This allows me to cross check Nexrad against what is happening in real time.  I frequently find differences during the cross check.

  5. SkyKing169 says

    This looks like a good business opportunity for someone to make a profit and bring to market a superior product that gives pilots the information almost immediately at an affordable price.
    Who’s working on it?
    When can we expect it to be available?

  6. Dave says

    XM weather makes it clear that the WX picture can be old.It should be used as an indicator for long range planning to give you a route around weather. Airline onboard dopler radar requires 22miles standoff from level 5 returns, this should give you a feel for how fast a cell can grow deadly. DR the weather ahead 20 min, add a standoff of 30 miles and go around it. 

  7. Kip says

    I feel Iike i have been mislead. THis is not a good tool at all then for weather avoidance. In fact I would consider it worthless.  Is the ADS-B weather a better source?

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