Hello Vilas,
I think this recommendations is just to be on the safe side as if we are not 100% sure it’s safe, then we must implement safety rules such as no cellphone during taxi and take off and landing. We all know this is horse **** but they still forbid us to use our phone.
For the weather radar, I know so cause I sent an Email to the manufacturer and they confirmed me it was not hazardous at all to humans.
Here’s the reply:
Hi Gregory,
Sorry for my slow reply. I recently retired from Rockwell Collins and now work contract for them. So I am not regularly checking my email. In the past, with very old weather radars, it was common practice to turn off the radar whenever there was no significant weather because you quickly wore out the magnetron. Today's digital radars no longer use magnetrons and have a very long life. So we recommend having the radar on from push back to taxi in. With that said, over time there will be wear and tear on the gears and bearings in the pedestal. And although Rockwell Collins has a very low failure rate for these components, they are a mechanical system and are subject to failure. So some airlines elect to keep the radar off during operations to reduce the mechanical wear and tear.
And I think this was mentioned in the Cathay video, but the radar is a very minuscule radiation hazard... less than standing in front of a micorwave oven. So it is safe to turn it on during taxi.
Sincerely,
Steve