On-Board Weather Sensing Information

[efarbstein]

Looking to find more info on on-board weather sensing systems available to pilots. To clarify, this does not include ground-sourced ATC relayed observations. My scope is weather information directly available to the pilot from the aircraft's on board systems.

I'm looking specifically at major airlines in the US, and the mandated minimum requirements for those aircraft.

If anyone could tell me a bit about these systems, or let me know where I could find more information, I would very much appreciate it!

Thanks:)

[bucket_and_spade]

I fly a B757 with technology representative of most modern airliners flying today (in terms of 'weather sensing' ability)...although it is an old design!

We have a temperature probe which measures the temperature near the nose of the aircraft. As we're moving through the air at speed, what is measured is actually higher than the actual atmospheric air temperature due to our forward motion - computers on board correct for this and calculate the outside air temperature then display it.

The aircraft can also calculate the approximate wind direction and speed at it's current position by taking information from the inertial reference units and other sources.

We also have a weather radar which picks up reflections from moisture (usually) in the air, sometimes hundreds of miles ahead of the aircraft. Different intensities of radar return display as different colours and from this, their range, shape, what we can see out of the window (!) etc. we can try to interpret what the returns might be e.g. a thunderstorm, a rain shower, ground returns, etc.

Linked to the above is a windshear detection system - this uses the weather radar and other signals to warn of possible windshear ahead of the aircraft.

All of the above is standard equipment on airliners. Certain items/systems above may be required to be operating before departure, others may be OK to dispatch with broken (but operational conditions might apply, for example).

Sory if this is a little too basic for you!

[MarkerInbound]

121.305 says you have to have a free air temperature indicator.
121.357 says you have to have weather radar.
121.358 says you have to have a windshear warning system.
25.773 says you have to have a window. (You didn't say who's doing the sensing.)

That's all that is required.