FAA SAIB AIR-21-18 - Conflict of Frequencies Used By Manufacturers

If you have a radar altimeter in your aircraft, it may not work in the future. Please read the attached SAIB on this matter.

Scott Sherer
Wright Brothers Master Pilot, FAA Commercial Pilot
Aviation Director, Piper Owner Society Forum Moderator and Pipers Author.

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  • I think for almost all GA pilots in piston planes this is mostly advisory. For commercial flying Cat II/III approaches it is a nightmare as radar alt can/is required.

    All because people want faster cat videos on 5G.

    The next nightmare is the FCC sold off the freq band adjacent to GPS and the spillover is likely to make GPS unreliable near things like airports or even enroute.

    Luckily we have LORAN as a backup as well as a robust network of VOR's. Hey - wait a second! Where did they all go???



    Eric Panning
    1981 Seneca III
    Hillsboro, OR (KHIO)

  • I performed GPS antenna design work as well as GPS digital database QC for the US Navy for 21 years. In addition, I was an airspace manager for the USAF for four years. I warned the USAF, USN, RTCA and FAA not to discontinue LORAN-C, enroute VORs and NDBs just for situations such as this. GPS has a broadcast volume of -157dB and the older satellite transmissions are 10w from 11,000 miles. This is the power of your refrigerator light! GPS is extremely easy to jam, miji and meacon. When one satellite is down in the constallation, it will not affect just one airport but an entire region (FDC & RAIM stuff). VORs and LORAN are so far off the 1.4 GHz spectrum, that any interferance with one system will not affect the other. All this was done to save money and had little to do with any safety of flight issues.

  • edited November 2021

    Thank you for your service bearair70. Another reason for redundancy is space weather is unpredictable but could be disruptive. We have never had so many satellites in orbit and are just coming out of a solar minimum. Last three big storms were 1982, 1989, 2013 and there have been a number of near misses. There is enhanced warning of ~ 18 hrs or so which is better than historical. Unfortunately an exceptional storm is going to impact space and land based navigation but I think the risk is prolonged degradation to the GPS network.

    I have had to upgrade to a better quality of whiskey for my compass due to declining magnetic field strength.... ;)

    Eric Panning
    1981 Seneca III
    Hillsboro, OR (KHIO)

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