[REPORTED] Radar altimeter shows height through deck when off

Nooch · April 11, 2019

When parked on the carrier on a cold start with the radar altimeter off, it does not display zero. Not only that but it reads the aircraft height above the water, somehow sensing through the carrier deck. When switching it on, it returns to zero and correct height starts being displayed. Track included below.

hornet radar altimeter issue.trk

Edited April 16, 2019 by Nooch

Nooch · April 16, 2019

I know it's a small issue but please consider reporting it. Thanks.

XtraChrisP · April 16, 2019

I don't think this is a bug, as you stated the radalt is OFF when you cold start so it's not sensing anything until you turn it on. I think that the 60 or so feet indicated is normal for it being unpowered? I've never had any issues with the radalt, and can confirm that both a) as I fly over the carrier deck my radalt drops 70 feet (since the deck is 70 above the water line) and b) when I fly over other aircraft it senses my 'height' above the other plane.

Anyway, as long as the instrument works as intended when the power switch is on, I don't think we need to be concerned about it's 'operation' when it's off.

Nooch · April 16, 2019

I think you didn't read my post properly. The issue isn't that it shows something other than 0 when it is off. That could be a normal thing, as you said.

The issue is that it shows 60 feet when you are starting up on the deck. It doesn't make sense for a radar altimeter. It's like it was able to see through the carrier. Plus this happens to be inconsistent with when you turn the thing off manually, where it shows the height between the sensor and the deck (about 3 feet or so) which makes a lot more sense.

Edited April 16, 2019 by Nooch