ForeFlight Sentry combines ADS-B receiver and CO detector

3 min read

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.

26 replies
  1. James Gibertoni
    James Gibertoni says:

    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?

    • Braulio.
      Braulio. says:

      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.

    • John Zimmerman
      John Zimmerman says:

      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.

    • John G
      John G says:

      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. Nathan
    Nathan says:

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

  3. Phil
    Phil says:

    How does the Sentry compare to the Stratus 3 unit? I only use the ForeFlight app and will continue to do so.

    • John G
      John G says:

      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.

  4. Michael Brocoum
    Michael Brocoum says:

    The Sentry unit also has a standard camera thread on the bottom to use instead of the suction cup.

  5. Kerry
    Kerry says:

    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.

  6. Jim
    Jim says:

    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?

  7. rdunlay
    rdunlay says:

    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.

  8. Tony
    Tony says:

    So as a commercial pilot I have since purchased the Sentry and have several critiques about it after having flown several hours with it now.

    First the negative. Yes, it does offer CO2 monitor and at a glance it would make one believe that it is the better of the two when comparing it to the Stratus 3 for that one feature. However, when you test the alarm on it while in flight (through the settings) it is hardly audible over prop noise. At first I thought it was due to my Bose A20 noise cancellation. But even after taking off my headset it is still hardly audible, having to put my ear up to the device to be able to hear it. You would not know it though if you test it on the ground because with no prop noise it actually seems like it would be loud enough.

    Next, I’m not sure if it is only my device, or if others are having a problem with this also, but it seems my Sentry device also continues to disconnect from my iPad. I will have green all the way across on the Sentry device it’s self, but it seems that through its connection through WiFi that it just continues to drop. This is quite aggravating, especially if you’re using it for its main purpose, the GPS. Ive tried resetting my network on my iPad and also shutting down the iPad completely and turning it back on. I’ve moved my Sentry device to several locations in the aircraft and have also closed out all other apps that could be interfering with the signal and yet it still continues to drop. So it’s one of the more frustrating things I’ve dealt with while owning it.

    However, the positives are this. The suction cup is strong enough to hold its weight where I’ve seen that be an issue with the Stratus. When it does work, it doesn’t seem to drain my iPad nearly as fast as the Stratus 2 did from processing. I could have 15% remaining on my iPad with the Stratus 2 and it would shut it off any lower than that from how much power it uses. And the biggest perk about the Sentry is that it’s own battery power lasts quite long. I can fly nearly 3 full days before needing to recharge it where as the Stratus 2 I was only able to make maybe half a day before needing to recharge. That’s a pretty big difference.

    All in all, if I could resolve the connection issue I would highly recommend this product. When it’s conncected it does all as advertised even if the CO2 alarm is maybe too quite to be heard over the prop. For the price it’s hard to beat and it’s why I’m sure that even with the release of the Stratus 3, they had to lower their starting price drastically to compete with the Sentry. And who knows, maybe I’m just having issues on my end with the connection and everyone else is doing just fine. This is just my observation on the newly released Sentry. I would say though if you’re one of the few who does not use ForeFlight but some other kind of flying app then that’s where the Stratus will shine as Sentry is only compatible with ForeFlight.

    Hope this helps all who are finding it hard to choose between the two products.

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