J41 radar altimeter question

[metzgergva 28]

Hi, just would like to know if a RA readout on ground of 5 is correct or do I need to adjust it somewhere. On other planes I have 0 on ground.

[downscc 1,327]

I am just guessing here, does it vary with airport? If so, then it's the difference between simulated height and actual data. Probably not, just curious. Also, some installations report height above ground of the radar antenna rather than the tires. Not sure what the JS41 should be indicating on the tarmac.

[JetJock_YHZ 0]

I am just guessing here, does it vary with airport? If so, then it's the difference between simulated height and actual data. Probably not, just curious. Also, some installations report height above ground of the radar antenna rather than the tires. Not sure what the JS41 should be indicating on the tarmac.

If my memory serves me correctly, the radar altimeter antenna is located in aft lower fuselage, making it about 5 feet above the ground (to the nearest 5 feet).Carl Warren

[aentwis 61]

Now the question is, whether the real world aircraft's radio alt system is corrected for the difference between the ground and the position of the antenna...:(Andrew

[downscc 1,327]

Andrew, if so then the correction would only be correct at a given pitch. I've only flown a C-414 with one of these devices and it was analog, the readout has no meaning on the ground but comes into play when flying an approach with a DH minima.

[JetJock_YHZ 0]

Now the question is, whether the real world aircraft's radio alt system is corrected for the difference between the ground and the position of the antenna...:(Andrew

No, it is not, on this aircraft, nor any other one I have ever flown. In a 767, it reads 20' on the ground.Carl Warren