ForeFlight Sentry combines ADS-B receiver and CO detector


One year after releasing Scout, a tiny ADS-B receiver manufactured by uAvionix, ForeFlight unveiled the follow-on product at EAA AirVenture this week. Sentry is larger than Scout but also packs in a lot more features, including GPS, AHRS, and even carbon monoxide monitoring. At $499, it’s a compelling package.

Weather and traffic

ForeFlight Sentry
Sentry mounts to a side window with an included suction cup mount.

It seems like table stakes these days, but the subscription-free weather and traffic available with Sentry is still the most important feature. Just like a Stratus or GDL 50, there’s nothing more to do than mount it and turn it on. Sentry connects to your iPad via WiFi, and accommodates up to five devices. Simply open ForeFlight and you’ll start receiving the full list of ADS-B products, from radar to METARs to PIREPs.

Reception seemed good in our test flights – we had weather at about 500 ft. AGL around Sporty’s, and updates came in reliably. With the full ADS-B network built out now, details about reception are less important than they once were. In fact, ForeFlight no longer reports the number of towers you’re receiving, only the overall quality.

We also tried the new Glance feature in ForeFlight synthetic vision to locate nearby traffic. It’s pretty slick.


Two important features Sentry has that were missing from Scout are GPS and AHRS. The addition of these two – plus a built-in 12-hour battery – makes Sentry a complete iPad accessory, driving moving map screens, terrain alerts, and a full synthetic vision display. ForeFlight shows a handy setup screen the first time you connect, which ensures you get it mounted properly:

Tapping the SETUP SENTRY button brings up a second page, which offers three choices for mounting location: left window, dash, or right window. Then there’s a button to zero pitch and roll on the attitude display.

Carbon Monoxide

Sentry is the first ADS-B receiver to include a carbon monoxide detector. This will be most helpful for piston airplane pilots in the winter, since many cabin heating systems are susceptible to exhaust leaks and potentially serious CO poisoning problems. The middle light on Sentry is for CO – it’s green when normal, yellow when CO is above 35ppm and red when CO is above 50ppm. There’s also an audio alarm and a pop-up alert in the app.

Sentry menu ForeFlight
Complete status information, including CO level, is available in ForeFlight.

We tested this using a car exhaust system and it works. The alarm is loud enough that you would probably hear it in the cockpit, and the app alert is also quite noticeable. We didn’t see the CO value change in ForeFlight until it alarmed (it stayed at 0 in our testing until going straight to 1000), but after a few minutes the light on Sentry did turn red and warn us. That’s what counts, and we think this is a nice addition.


Sentry is designed to work with ForeFlight, so complete status information is available in the app, including battery life, GPS status, and various settings. Firmware updates are also easy to do directly in the app.

Sentry is now available for $499. It includes a charging cable (no wall plug), carrying case, and a suction cup mount. The mount has a quick-release mechanism so you can connect Sentry to the mount in about a second. It’s intuitive and easy to do. There are no options for external antennas, so you’ll need to mount it on a side window. Sentry charges using a USB-C cable, which is a rugged and increasingly common choice.


  1. What’s the weight compare to stratus? Got an original stratus now. Climb from S/L to 12.5 and every time it falls off the window. Same thing happens to at least dozen of my friends. The suction cup is not strong enough to support the unit. Again, is this the same with this unit?

    • I got it and tried it since it came out, it’s very light and the ram suction is very strong. I don’t think you will have an issue with this falling off. I am very happy with the purchase.
      Hope this helps.

    • The GPS and AHRS work anywhere in the world, so you’ll have moving map and backup attitude in Canada. Traffic will work, but you’ll only see ADS-B Out airplanes. Weather only works in the US so you’ll need to be close to the border to get it.

    • It’s supposed to be viable for ten years. You’d need to ask the customer service department at ForeFlight if they’ll offer CO2 detector replacement. However, in ten years I’d guess that you’d probably find it less expensive to simply buy a new, probably vastly improved unit.

  2. If I remember correctly, Stratus 1 & 2 preferred an IPAD with cellular + WiFi. Will a WiFi only iPad be sufficient for the Sentry?

    • The site wrote an overview of the 3 recently, so take a look at that for the details. In brief, the only features that the 3 has that the Sentry lacks are a flight recorder, though that feature is promised in a future update, automatic shutoff, and support for other EFB’s. If all you ever plan to fly with is FF, though, the Sentry seems like a pretty good bargain vs the Stratus 3, especially for the CO2 detector.

  3. What is best solution if just want AHARS? I have ADS in/out, weather w connection in plane. Would like to have back up AHARS.

  4. I have a Glasair with the GPS Garmi-530 WASS antenna located on the inside ceiling of the A/C. It works very well. Would the sentry work there? Also can you use a cigarette lighter/USB to power it? If it’s hooked up to an avionics switch will it come on with the switch?

  5. Does sentry use the GDL-90 software protocol? If no, are there plans to update so it can be used on android-based tablets? Is it compatible with EFB platforms other than Foreflight? If no, are there plans to do so? Thank you.