What does ADS-B weather look like?
The FAA’s network of ADS-B ground stations has made it easier than ever for pilots to view datalink weather in the cockpit – without paying a monthly subscription. Everyday, thousands of pilots are flying with portable receivers like the Stratus, Garmin GDL 39 or Dual XGPS 170 connected to their iPads.
If you haven’t taken the plunge yet, come along as we take a look at all the weather products you’ll see with an ADS-B receiver, and how each can be useful for making flying a little easier and safer.
This is arguably the most popular of the weather products available, and provides a full-color depiction of precipitation and thunderstorms right on the moving map. The system will show detailed regional radar imagery within 250NM of your current position, and is updated every 5 minutes. Remember though that the real age of the weather is likely between 5 and 10 minutes old, so it should only be used for long-range strategic planning, and never for close navigation around thunderstorm cells. Beyond 250NM of your position you’ll see radar imagery with slightly less detail, called national radar, which is updated every 15 minutes.
This image shows both types of ADS-B radar, with the high-resolution regional radar displaying near the present position in Georgia, and the blockier national radar picture showing precipitation in Mississippi:
Radar imagery can also be viewed as a layer on top of sectionals or IFR en route charts, making it easy to plan out a diversion while still a ways a way from hazardous weather:
Textual METAR, TAF and Winds Aloft reports/forecasts can be found in a few different places in ForeFlight. The first location is in the Weather section of the Airports tab. Notice the ADS-B label next to the age of the report, confirming the source of the data:
You can also tap on an airport directly from the moving map to bring up the METAR, TAF or Winds. Notice in this image that the Flight Rules option is selected, color-coding the airports based on whether they’re reporting VFR, Marginal VFR or IFR:
Here’s a shot of the Winds Aloft forecast:
Pilot reports have traditionally been presented in text format, and required you to visualize the location based on a VOR radial and distance. ForeFlight makes the interpretation of PIREPs much easier when using ADS-B weather, and plots the location visually on the map with different icons based on hazards in the report, like icing or turbulence. The ability to view the context of these along with radar imagery makes them a great in-flight tool:
Just like on the ground, AIRMETs and SIGMETs are presented graphically, and you can tap on them for additional information:
Having temporary flight restrictions visually depicted in flight provides additional assurance that you’re flight path will stay clear of this restricted airspace. ForeFlight will also display blanket TFRs for large sporting events from the ADS-B feed:
NOTAMs are accessed from the Airports tab in the NOTAM section of the screen:
In addition to weather, the ADS-B system also transmits traffic information. While this subject is complicated (read our detailed explanation for complete details), when traffic does work it’s a great help for situational awareness. Traffic shows up on the moving map page, and you can tap on a target for more information:
Many ADS-B receivers also include an Attitude Heading Reference System (AHRS), which provides backup pitch and roll information. This can be viewed as an attitude indicator:
Some apps also show a synthetic vision display, with 3D terrain and obstacles:
Want to learn more about the ADS-B system? Watch our webinar:
You can compare the best-selling ADS-B receivers here.
I’ve been flying with the ForeFlight AHRS now for several hours and am not yet totally convinced of the efficacy of its intended AH backup capability. The bank indications of the FF program seem to lag and not always consistent with the direction of turn and bank. I’d like to develop 100% comfort level with the FF AHRS as a worthy backup to the very basic IFR instrument legacy airplane which I regularly fly. What can you tell me to make me more confident of the reliability, safety and efficacy of your AHRS system in the event of an actual failure of the certified panel installed instrumentation?
The AHRS is definitely not for primary use – since it’s not permanently installed, it’s only as good as the initial setup – but I’ve found it to be very good for backup and general situational awareness. It should definitely not lag, since it’s updated multiple times per second. While it may not match your panel exactly, it should be within a degree or two.
1) Mount Stratus first, then turn it on. If you turn it on, then go to mount it, the unit will try to auto-calibrate while you’re still moving it.
2) Make sure the lights on Stratus face the tail (that is, it’s parallel to the direction of flight) and make sure it’s stable. It doesn’t have to be perfectly level, but it needs to be in a fixed location.
3) Preflight the backup AHRS just like you preflight the rest of your instruments. Make sure it looks correct before you start taxi.
4) Calibrate the AHRS before flight or shortly after reaching cruise (if needed). Tap the gear symbol on the AHRS screen, tap calibrate, then either adjust one degree at a time or tap “zero pitch and bank.”