Originally Posted by
Sallyann1234
And still the issue is dealt with in the US on the basis of 'potential' and 'possibility' and 'likelihood' of interference to altimeters, which therefore requires extensive precautions and operational restrictions.
Has anyone yet demonstrated or reported actual interference to altimeters, of an extent to require these restrictions?
Are these restrictions to be maintained indefinitely, in the absence of proper tests?
Meanwhile the rest of the world has made its assessments, and got on with life as normal.
It’s not quite that simple. When systems are certified, they must be demonstrated to comply with the standards of performance in conditions that represent those expected to be found in service. Any certification applicant could justifiably object if performance tests were required in more challenging, nonrepresentative conditions. Radio altimeters and the flight control systems they interface with have been certified to meet known requirements in the appropriate conditions.
Now the the conditions are changing. Radio altimeters had been certified to sufficiently reject interfering signals and continue to meet required performance standards when 5G transmission in nearby wavelengths were not present. There was nothing wrong with these approvals. But not all currently approved radio altimeters type designs would be able to perform with the necessary accuracy and assurance in these new conditions.
One may point fingers only at the FCC and FAA, but remember they operate in the midst of powerful and disparate political influence by corporate interests and powerful politicians they support and rely on.