With much talk about modern avionics in recent years, from glass cockpits to ADS-B, one fact remains unchanged: most aircraft have vacuum systems and gyroscopic instruments that sometimes fail. Although, there are pilots flying today’s skies that have never seen a gyroscopic instrument or have had to execute an NDB approach—with such instruments covered—there are many aircraft currently trolling the clouds relying on “old school” gyros.
Sadly, pilots are still perishing when these archaic instruments (or the systems that power them) fail. Recently, a Bonanza pilot and two passengers met an untimely end when a vacuum pump (being operated eleven years beyond its service life limit) failed. While newer aircraft have the luxury of fancy glass—typically accompanied by one or more backups—much of the general aviation fleet still relies on suction and spinning gyros. The question remains, why do many pilots continue to fly without redundancy, especially considering the power that most of us carry everywhere we go?
My Phone Can Do What?
I’m referring to the handy smartphone. You probably know that it has more processing speed and memory than the computers that took us to the moon. But, did you know that most smartphones have a suite of sensors that are fundamentally equivalent to modern avionics systems ordinarily serving as components of glass cockpits? Some examples of onboard sensors include accelerometers, gyroscopic sensors, magnetometers, and barometers. These can provide the detection of attitude, gravity, linear acceleration, and heading. Also, GPS and cellular signals are used for position and speed information.
In short, the typical smartphone has capabilities that go beyond phone calls. New glass standalone instruments have recently been introduced, such as the Garmin G5 and Dynon D10 that essentially have the same innards found in a cellphone. While these new instruments are “relatively” cheap—starting at $2000—you can harness some of the power of the smartphone in a pinch. Let’s take a look at some examples with a note of caution. This is not a comprehensive review, simply my observations of a variety of products. Nor do all applications tested work with both iOS and Android platforms.
While there are many different smartphones and a range of applications for each, we’ll focus on the iPhone Model 8 and associated apps flight tested under visual flight rules. Currently, no app can be used as a legal backup for several reasons. First, no app allows you to pull out a phone after an instrument or system failure and have it be calibrated for safe flight. Having the app set up and suitably secured/ oriented in the cockpit is required before it’s needed.
The only way to validate if an application has the essential utility is to do some testing that must include finding a location to mount the phone in a low vibration area, and secure position within the field of view.
My evaluation included several apps, though technically only three of those tested claim to be standby instruments. The first was iBFD, which has a glass-cockpit-like display. This app must be calibrated precisely and placed in a location and position within the cockpit so the attitude matches that of the aircraft. Simply, the application has no way of being “zeroed” when flying in level flight. This makes the real utility of this option questionable. Its display of attitude was extremely sensitive and jerky, so it doesn’t react like a flight instrument—even glass.
The vertical speed, airspeed, and altitude features seemed accurate, although the “airspeed” provided was actually groundspeed. However, the heading feature was good enough to use in lieu of a sloshing compass, if needed. Overall, this application has limited use as a backup attitude indicator, but could provide critical data in case of other system failures; such as a frozen static port or a failed directional gyro.
The next app tested was ShcumApp, which can display a conventional attitude indicator or a glass-like display. This app can be “zeroed” regardless of initial phone orientation, so it can be synced to straight-and-level. Once calibrated, the display was consistently accurate, though, like iBFD, somewhat sensitive—moving instantly with slight changes—especially in turbulence. It could function as a reasonable backup. It also has the advantage of digitally displaying degrees of roll and pitch. It does lack other data such as heading, speed, and altitude.
The most capable application as a realistic stand-in for an attitude indicator is Horizon. It provides a display that looks like a high-end gyroscopic AI. It can be calibrated in any position, and it provides flexibility for cockpit phone installation. The best part about this app is that it has a dampening feature, which makes the movements smoother and less prone to vibration. The pitch and bank action of this application are much like a real gyro. Additionally, the digital pitch and bank angles are provided. Just like ShcumApp, there are no heading, altitude, vertical speed, or airspeed indications.
There are many navigation and flight planning apps available and often accessed through subscriptions. Some of these offerings have “pseudo-instruments” that are reasonably accurate. Garmin Pilot has an array of possible backup instruments available that include airspeed (groundspeed), altitude, heading (track), and vertical speed. While not perfect, this suite of instruments could save your life if things get bad in the cockpit.
A wide range of sensor apps can display raw data, which can be used during flight. One example is Sensor Kinetics that provides acceleration, gyroscopic data, a magnetic sensor, gravity and a basic attitude indicator. While this data is not usable to maintain precise flight, it can be used as a reference to aid in dissecting flight conditions. This app also offers flight recorder-like output, which can be helpful for flight instruction as well as historical flight monitoring data such as vibration, G-loads, and more.
Not all applications are worthy or even safe for use. One application tested, AOA Flight Assistant, means well, but doesn’t deliver. This software aims to provide pilots with guidance on angle-of-attack. The initial setup of the app takes extensive tweaking to ensure that the referenced angle-of-attack is accurate, including inputs for angle-of-incidence and initial airplane attitude, though it also provides an option to calibrate the system according to the position of your phone in the cockpit. During in-flight testing the outputs provided were essentially useless because of the lag of the display behind the actual aircraft attitude and its propensity to be affected by turbulence and vibration. Perhaps with more engineering, this might eventually provide useful data. Pilots should carefully evaluate any app they intend to use before needing it. Such evaluation should take place in the specific aircraft in which it may be used—including the proper mounting of the phone.
Evident from the rapid improvements in smartphone technologies, are many tasks these devices do for pilots that were previously only possible in our dreams. In aviation, we continually need to keep abreast of potential resources that can make flights easier and safer—especially if something goes astray with the aircraft. However, use care not to adopt something just because it’s available—evaluate your options and don’t introduce something that, in the end, makes life more complicated or distracts from the essential tasks at hand. Technology often provides a double-edged sword, too much—or used in the wrong circumstances— can have an adverse effect. But when used properly, and at the right time, it can be indispensable. Consider apps available for your smartphone and give a few a try.
David Ison, a former B737 and L1011 airline pilot with over 6100 hours, is currently a professor in the Graduate School at Northcentral University.
This article originally appeared in the April 2019 issue of IFR Refresher magazine.
For more great content like this, subscribe to IFR Refresher!
David, I just looked up one of your recommend apps, Horizon (for android). As there was no links in your article to the apps – the one that I found on Google Play named Horizon hasn’t been updated since 2012. Could you provide links to the apps you described?
I do not use Android so I am sorry that I cannot provide guidance on Google Play apps.
Nice article David. I’ve been active in flying clubs and FBOs that do rentals for years. With the exception of 1 available Cirrus SR20 everything else is steam gauge. I utilize Seattle Avionics FlyQ efb which was first available for my iPad and then later for the smart phone as well. I use a portable suction mount for the iPad which has been rock solid staying in place on the windscreen and obviously travels from aircraft to aircraft as needed. All the basic attitude instruments are right there on the screen of the iPad so it indeed is an awesome backup of the primary aircraft instruments. And yes, one of the aircraft I flew recently still had a working NDB. In the old days the NDB was an asset to bring local AM broadcasting to the cockpit as well. This was before music streaming and smart anything in the cockpit 🙂
Yes the Seattle FlyQ is great – I have played with it a little using a “homebuilt” ADS-B receiver (for about $60) and am able to see local traffic. Neat stuff but as always – as you say – we have to remember to fly the plane first!
If you’re routinely and regularly flying “hard” IFR using vacuum system powered steam gauges and are concerned, why would anyone use a cell phone running a dubious app as a backup? There are plenty of other potential items of portable equipment that’d do the job MUCH better and don’t take up much space in a flight bag these days. They’re no more ‘legal’ than the cell phone but do offer better performance, larger displays and were originally designed for aviation use.
The updated Dynon D3 w/ a suction cup mount would be an excellent backup worth having. The Garmin Aera 660 along with a GDL 50 would offer a full up six-pack panel like display PLUS ADS-B TIS-B traffic plus maps. I’m in love with that thing … SO much so that I’m considering buying a second and hard mounting one and using the second on the yoke. And, I never fly out of the local area unless I have a hand held radio at the ready; the new Sportys PJ2 with headset connectors is on my wish list soon. With it and the Aera 660 / GDL 50 pair, you could navigate, keep the grass under the airplane and see some traffic while you communicate in an airplane with complete electrical and vacuum system failure. If you own the airplane, installation of a new Aerovonics AV-20 would be a VERY wise backup safety investment for less than a grand. Just this week, Paul B did a superb in flight video on the Aerovonics products in his non-electrical, non vacuum powered Cub elsewhere on Avweb. The AV-20 doesn’t cost much more than a cell phone.
Another point of consideration is a backup position source IF the primary source for a non-GPS capable iPad failed. I carry a BadElf but the Aera 660 will communicate via Wifi OR Bluetooth to do the same job. Not mentioned, a backup USB power source would be a good idea and doesn’t take up much space.
The cell phone would be the last item I’d consider for primary backup instrument use. It’s a great way to call for help after the fan stops running IF it comes to that. Unlikely that it’d survive a crash mounted in the open. I know people that now carry an inReach device full time for emergency communication, too.
Larry you are spot on. This would be the absolute worst case scenario to have to resort to an APP. A few things to consider when using anything as a back up – “legal” or otherwise – is if you haven’t practiced with it AND it isn’t ready to use at any moment, it’s useless. Regardless of the tech you use, if it has “standby” instruments that one attempts to resort to in an emergency and either of the aforementioned requirements doesn’t apply, then you may be worse off trying to fiddle to use it. I am not recommending that someone use an APP on their phone that’s in their pocket when their vacuum system fails!
On a different note, the guts of a cell phone and any “legal” AHRS or other guidance these days are essentially very similar (if not the same). All solid state, accelerometers, GPS, even baro sensors are all packed into tiny places. It’s all very impressive but with limitations. Thanks for the feedback – you make great points.
I am not looking for an approved aircraft instrument panel, just something that will get me down alive when things fail. OK so the FFA doesnt like it. I dont care if I am standing on Terra Firma and the plane is not broken too bad. The comment that the cell phone would be the last thing to consider for a primary backup is true, but not valid in this context. GET ME HOME….I dont care how or if Big Brother likes it.
Thanks Jim – you are right. But if your phone isn’t already handy and basically set up to use, it probably won’t help. But yes, you’re also right that anything and everything to get you back to the ground is fair game. When was the last time any of us asked to practice a “no gyro approach”??? Can a controller even do it anymore?!?!
That should ne FAA, not FFA but I also dont care if the Future Farmers approve of it….just keep the corn field trimmed close to the ground.