The second generation Stratus ADS-B receiver, the follow-on to the immensely popular Stratus 1, was announced last month at Sun ‘n Fun and is now shipping. With units starting to hit the street, many pilots have asked for a real world PIREP on how Stratus 2 works in day-to-day operations. We’ve been flying with the final version of Stratus 2 for over a month now, so we’ll share our experience here.
In spite of all the sophisticated features built into Stratus 2, the subscription-free weather available via ADS-B is still the most important one for many pilots. Just like Stratus 1, the new unit receives almost every weather product you would want: NEXRAD radar, TFRs, AIRMETs/SIGMETs, METARs, TAFs, Pilot Reports and NOTAMs. The only item that’s really missing from this list is satellite imagery. While the satellite picture is nice, this is really more of a pre-flight tool since it isn’t updated as often. In our experience, radar plus METARs are the critical ones for both VFR and IFR flying. TFRs are always nice to stay legal, and are a close second.
The other piece of good news is that the specifics of how ADS-B works (high vs. low towers, weather transmission rates) really aren’t important. In practice, radar is usually about 5 minutes old and text weather reports appear shortly after being issued. Coverage is also increasingly good. We’ve flown all over the country, and except for a few major holes (Kansas, Wyoming), we’ve almost always had good reception at altitude and seen the full national NEXRAD mosaic. Count on consistent coverage east of the Mississippi River, all throughout the sunbelt and up the Pacific coast. You don’t have to be on top of a tower to get reception. For example, at Sporty’s we’re about 30 miles from the closest ADS-B ground station, yet we routinely pick that station up at 200 ft. AGL with Stratus.
Our advice is not to get bogged down in the details–just fly. Recognize that ADS-B weather isn’t real time (no datalink weather product is), so it’s for strategic weather planning and not for penetrating lines of storms. But don’t obsess about the age of weather. At the end of the day, your eyes should always get a veto over anything you see on radar.
Also, don’t obsess over the number of stations you’re receiving–while we usually see 5-12 stations depending on location, one is all you need. There is zero benefit to seeing 8 vs. 6, for example. If your weather information is updating regularly, fly on.
The real power of the system is how the weather data is displayed in the app–good hardware is worthless without good software. Specifically, it’s all about the ability to view weather data in context. We’ve all heard the Air Traffic Controller say, “Convective SIGMET from 40nm south of Nowhere to 60 east of Nowhere…” That information is hard to put into use. But a graphical depiction of a SIGMET, overlaid on a sectional chart and with your airplane’s position is extremely valuable. On top of that, each weather overlay reinforces the other–if you hear a PIREP for severe turbulence, it can be comforting to see that the airplane was right in the middle of a red cell and not just flying in clear air.
Information in context is always more powerful, and the iPad makes it easy to zoom in and pan around for more details about weather. This isn’t necessarily specific to the Stratus, but it’s an important point when considering iPad-based weather maps vs. other sources.
Most pilots worry about mid-air collisions (even though the statistics show it’s low on the list of accident causes), so the promise of free traffic via ADS-B has always been appealing. And Stratus 2 does include a dual band ADS-B receiver for the best possible traffic picture. But due to the nature of the system, “best possible” still isn’t very good unless you have a panel-mount ADS-B Out transponder in your airplane (like the Garmin GDL 88).
Without getting into all the details (you can read those here), our experience is that you won’t see many traffic targets that are real threats. In general, you’ll see plenty of airliners up high (who have ADS-B Out), and you’ll see lots of traffic if you fly near areas with a lot of ADS-B Out airplanes (UPS in Louisville, KY or Embry-Riddle in Daytona Beach, FL). Occasionally you’ll also fly close to another airplane with ADS-B Out, which will light up a ground tower. When that happens, you can get a pretty decent view of nearby traffic. In fact, sometimes the traffic can be overwhelming, so we have come to really appreciate ForeFlight’s “filter traffic” feature, which is selected from the gear menu on the Maps page. This hides traffic that isn’t within +/-3500 ft. and 15nm radius of your airplane. So while you will often see traffic that is hundreds of miles away, it’s of no value. Turn on the filter and focus on nearby traffic.
In general, we wouldn’t depend on ADS-B traffic for anything more than supplemental information. It’s simply too spotty to be of much use unless you have ADS-B Out in your airplane. If you do equip with ADS-B Out, the story changes dramatically. In this case, your airplane will cause the ADS-B ground stations to transmit a complete traffic picture back up to your Stratus, so the overall traffic picture is spectacular. You’ll see almost all traffic–including non-ADS-B Out targets. And ForeFlight’s traffic display is pretty clean: each target shows relative altitude, speed, projected track and N-number (if available). You can tap on a target for complete details.
Should you add ADS-B Out to your panel just to get better quality ADS-B In traffic? Maybe. If you fly in high traffic areas, it may be a smart investment, since you’ll have to equip with ADS-B Out by 2020 anyway. But if you don’t feel like spending the money on a panel-mount ADS-B transceiver, we certainly wouldn’t view that as a mistake at this point.
The inclusion of an Attitude Heading Reference System (AHRS) in Stratus 2 adds significant new capability for a portable device. Most importantly, it means pilots can have an accurate attitude backup–a valuable safety feature if your airplane has an aging gyro. The AHRS is completely self-contained inside the Stratus case, so there’s no installation or wires. It also has some fairly sophisticated auto-calibration features, which is a real time-saver. In most airplanes, we simply turn on Stratus, place it in the dash mount and go flying.
That brings up the question of mounting, and the good news here is that Stratus is flexible. It snaps into a hard plastic cradle, which sits on a non-slip silicone pad. The unit does not have to be perfectly level on the dash, and it will sense which way is up or down. The only limitations are that the lights on Stratus should point to the back of the airplane, and the unit shouldn’t slide around in flight (that’s true of any AHRS–stability is the key).
Once Stratus is on the glare shield and turned on, you can open the Stratus Horizon app (which is free). In most cases, that’s all there is to do. The app will display a large attitude indicator, which is updated multiple times per second for a smooth and quick-reacting display. Three tapes show speed, altitude and vertical speed–all of which are based on GPS data. Above the attitude indicator is a course indicator and below is a rate of turn indicator. It would certainly be enough to get you down to VFR conditions if you lost your attitude indicator in the soup.
If you do need to make a manual calibration–say, in a taildragger–tap the “i” button at the top right and you can adjust pitch and roll in one degree increments. Once in flight, if you need to recalibrate there is a handy “straight and level” button. Tap this and the attitude indicator levels out. This is a nice quick-fix feature.
It’s easy to switch between ForeFlight and Horizon, although in most cases ForeFlight is the most useful app. But one setup that we like a lot, and one that gives you both, is to run ForeFlight on your iPad and Horizon on your iPhone. It’s a complete backup suite. Of course, Stratus Horizon is strictly a backup and should never be used as a primary flight display.
Accurate position information from GPS isn’t a very exciting feature anymore–it’s expected with any modern avionics. But Stratus does eliminate the need for an external GPS like a Dual 150 or Garmin GLO with its built-in WAAS GPS. It’s also worth mentioning that the Stratus 2 features an improved GPS receiver compared to Stratus 1. We’ve obtained a GPS lock with the unit inside, far away from any windows, which isn’t possible with some GPSs. There’s also a GPS status light on the case, so you know at a glance if you have a good GPS lock.
Finally, the GPS enables a number of great ForeFlight features that have been recently added, most notably track up navigation and the Hazard Advisor. With Stratus and ForeFlight (a Pro level subscription in particular), you have a lot of information at your fingertips, from weather and traffic to attitude and terrain/obstacle warnings.
One of the most under-appreciated features of Stratus is its seamless integration with the ForeFlight Mobile app. The two were obviously built as a system, not an afterthought. In general, all the weather products work the same way via Stratus and the internet, so there’s no need to re-learn how to use the app. For example, radar is the same layer no matter what the source (some other apps have a separate FIS-B radar layer that can be confusing).
The best integration feature is the Stratus Status menu that is accessible from either the gear menu on the Maps page or from the Devices menu on the More page. The Maps page drop-down window is the best option–you can check on the age of individual weather products, see how many stations you’re receiving and check battery life while still viewing your moving map on the right 2/3rds of the screen. You can even dim the LEDs on Stratus from within the app, a handy feature for night flights (Stratus has an auto-dimming feature, but the manual adjustment is a nice added touch).
Firmware updates, which update the software that resides on Stratus and can bring new functionality, are easy to do right from ForeFlight. There’s no need to ever connect Stratus to a computer–new firmware is contained in ForeFlight and you can simply tap a button to update. It’s a small thing, but it helps
Stratus 2 ships with a non-slip dash mount, which works well in most airplanes. Again, Stratus does not have to be perfectly level to work. Our advice on mounting is to experiment–every airplane has a location that is the right mix of seeing up to the sky for GPS, down to the ground for ADS-B and not being excessively hot.
Stratus 2 is white and includes a fan, so is fairly resistant to high temperatures. We haven’t had any issues with overheating so far, but no battery-powered device is completely immune to extreme temperatures. Stratus will shut itself down before it becomes dangerously hot (just like your iPad). This is a good thing–just ask Boeing what happens to lithium batteries if they overheat. Again, for 90% of pilots, we don’t think heat will be an issue.
If you do fly in the desert and are concerned about heat, one good option is a suction cup mount. This gets Stratus up off the glare shield, which is usually the hottest place in the airplane. But it also improves GPS and ADS-B performance. Since you can see complete status information in ForeFlight, there’s no need to have Stratus within reach during flight. Mount it on a back window if you prefer.
Finally, Stratus 2 features remotable GPS and ADS-B antennas, so you can put the unit in a side pocket or even under a seat if needed. In this setup, you would run the two antenna wires up to a side window, where the short antennas attach with suction cups. Business jet pilots may find this to be helpful, especially with thick, heated windshields. This is also great for semi-permanent mounting, as some experimental airplane builders are starting to do. If you plan to hard-wire Stratus 2, select the “Turn on when powered” feature from the ForeFlight Stratus Status menu. This will automatically turn on Stratus 2 when power is applied, and turn it off shortly after you turn off the master switch.
Overall, our experience with Stratus has been very positive. The highest praise we can offer is that it just works–we turn it on and go flying. It’s certainly not perfect (for one, we’d like to see more AHRS integration into ForeFlight), but it has the feel of a second generation product: performance has been improved, features have been added and reliability is better. Like the iPad in general, it’s simply incredible the amount of information we now have at our fingertips. It would have been unthinkable just a few years ago.
For more information on Stratus, click here.