Is there a practical use of streaming data received from meteorological sensors installed on aircraft?

Question

I am not the practitioner in the field of aviation, and my knowledge is mainly theoretical. Therefore I would be happy to get a feedback from practitioners on the following topic: I was reading about the use of aircraft as meteorological sensors. I wonder how this streaming sensor data is currently used by pilots? Is it validated for logical consistency?

Moreover, I was thinking about possible applicability of such data, and in my opinion it could be used by Air Traffic Controllers for enabling/disabling airspace sectors for free routing (direct flight). Does it make sense from a practical point of view? This data could be shared via System Wide Information Management among different aviation stakeholders.

Answer 1

Yes, such a system would be beneficial to pilots, ATC, and meteorologists.

Pilots are very concerned with meteorological phenomena like icing and turbulence (for safety-of-flight reasons) and winds aloft (for fuel planning purposes). Pilot reports of weather conditions (PIREPs) may be delivered to ATC or Flight Service for local and long-range dissemination. This information helps other pilots avoid dangerous conditions and helps weather forecasters improve their forecasting models. The 7110.65 2–6–2 PIREP Solicitation includes a note:

Routine PIREPs indicating a lack of forecasted weather conditions, for example, a lack of icing or turbulence, are also valuable to aviation weather forecasters and pilots. This is especially true when adverse conditions are expected or forecasted but do not develop or no longer exist.

Live or periodic streaming of sensor information already present on larger airliners (particularly icing status, outside air temperature, and wind velocity, but other sensors could be installed as well) would relieve pilots and controllers of having to discuss routine PIREPs on frequency and could be developed into graphical systems that automatically display hazards. Delta is using vertical accelerometers in some of their aircraft to automatically report turbulence in real time and transmit that information to airborne flights; obviously they see this as a business advantage and are loath to share it, but the system could be expanded.

Whether the costs and complexities of such a system would be worth the real-time and forecasting benefits, I don't know.

Answer 2

"Streaming" implies a constant flow of data in a way that the available bandwidth of most present aircraft data/communication systems doesn't support. It isn't inconceivable to route those sorts of sensors to an aircraft internet connection, but the present state of things is much more based on ACARS -- which is essentially a text message. Sending a message every 10 minutes with winds aloft and temperature is entirely adequate resolution for the weather prediction systems, anyway.

It would certainly be possible to theorize a real-time wind readout from each aircraft to the controller so that he'd know the effect that wind would have when he gives a vector or a speed adjustment to an aircraft, but the value to be gained isn't all that great. If every aircraft on a given arrival flow has been assigned the same heading & indicated airspeed, they'll all end up doing the same thing, even if the controller is having to guesstimate the winds based on the delta to their ground track from his assigned heading. (Speeds never match anyway: assignments are given in indicated airspeed, but observed in groundspeed, which is true airspeed +/- the tail/headwind component.)

There is a case where it would be nice to have the wind values from a preceding aircraft, and that is in descent planning -- knowing the actual winds from cruise altitude down to 10,000' would allow a sufficiently smart FMC to build a more efficient idle descent path. Nice to have, but probably not such an improvement over the current state of forecast winds as to make a big technology investment worthwhile.

Likewise, knowing what the winds are at various altitudes could better inform the decision when & if to climb to a higher cruise altitude. Today, it's a matter of having a preflight weather forecast, and asking ATC if they have any aircraft at the other altitude that can provide a PIREP of winds and ride. Again, nice-to-have, but only that.

Answer 3

US weather forecasts generated by the National Weather Service are generated by a supercomputer running the US weather model in DC. That forecast is sent to National Weather Service stations across the country and compared with local observations. Corrections are fed back into the model for the next forecast. The NWS also releases radiosonde balloons to gather data for the model. A third source of data for the model are collected by airliners.

Modern transport aircraft can now constantly transmit data to the airlines operating them. There is a world wide network of VHF ground receiving stations and extensive SATCOM coverage for data and voice. On board communication management units use nav data to auto tune for the region they are in and select the most efficient com means for the data depending on nature and priority of the data. The real limitation is what an airline is willing to pay for. Some airlines use onboard sensors to collect weather data and they have a contract to sell it to the NWS, presumedly for use in the model.

There are thousands of aircraft operating in US airspace at any given time. I don't know how many are sending data, but it's an excellent way to obtain data across the country at any number of altitudes.