Logical Drive Aviation Software

What’s up?

We have decided to end the ‘Freemium’ pricing model for PocketHorizon™ and switch back to a standard single purchase (no more in-app purchases), AND we are now including AirNet™ Server for no additional charge.  We are doing this by replacing the old ‘Standard’ version of PocketHorizon with the new PocketHorizon™ Pro.  If you have the old app it will still work, but if you were in a trial period you’ll need to visit the App Store and purchase Pro since the in-app purchases no longer work.  The good news is that Pro includes AirNet Server for free!

Our Reviews

Unfortunately, due to the change to ‘Pro’ all our good reviews from the old ‘Standard’ are gone from the App Store – please don’t forget to add a review, or even just a rating, if you like PocketHorizon Pro.  Thank you!

Meanwhile, we’ve kept a bunch of reviews, and you can view them here!

iOS 7

PocketHorizon Pro has been tested with iOS 7 and no problems have been found, so we are pleased to tell you that the app is fully compatible with iOS 7, including the new iPhone 5S and 5C!



PLEASE NOTE:  THIS APP IS FOR PILOTS ONLY.  PocketHorizon Pro is a serious app that was created by avionics engineers/pilots who know how an instrument should behave.  However, recently with the old Standard version of PocketHorizon we were getting many downloads from users who were not reading the instructions or description, here or on iTunes.  Some were then leaving negative reviews because they don’t understand that this app ONLY WORKS IN FLIGHT, and will show unexpected behavior when tried on the ground.  For example, it returns to wings-level after a few seconds on the ground, but with forward motion in the air as detected by GPS it works exactly as expected.  This is part of the constant calibration of attitude by the GPS, and is why PocketHorizon Pro really works, vs. some others on the App Store.  See the FAQs and P.O.H. for more information, but if you are not a pilot or don’t like to read instructions PLEASE don’t download this app.  If you do try it, please FLY with it and give it a chance before leaving a review or rating.  Thanks for your understanding!



PocketHorizon Pro

What It Is

PocketHorizon Pro is a real Glass-Cockpit Battery-Backed Standby Artificial Horizon (Attitude Indicator) for your airplane, implemented as an app for Apple iPhone®, iPad® or iPod touch® iOS devices. It will use the internal (MEMS) Gyro if provided in your iOS device for quick response, or fully GPS-derived attitude if no Gyro is present, yielding accurate attitude but with slower response. iOS 5.0 and higher is supported as are most all Apple devices, from those as old as iPhone 3GS and iPod touch 3rd gen. to the latest iPad 4, iPad mini and iPhone 5, as long as they can run at least iOS 5.0. PocketHorizon Pro is a dedicated single-purpose app designed for pilots that wish to have a simple, modern standby horizon for use when they need it, on either their iPhone, iPad or iPod touch, with no subscription required. Even better, no manual calibration is ever required by PocketHorizon Pro; just configure it and fly. Great as a standby horizon on any airplane, or as the sole supplemental attitude indicator on smaller homebuilts, gliders, ultralights or even trikes … anywhere you can’t install a certified artificial horizon.

Requires (WAAS-Enabled) GPS!

NOTE that PocketHorizon Pro requires an external WAAS (EGNOS)-Enabled GPS for proper operation even when an internal Gyro and/or internal GPS are available, for two reasons. Firstly, the internal Apple Gyro is subject to significant precession and other errors over a short time, and thus a critical part of the attitude calculation must come from GPS Track, Altitude and Groundspeed information. Secondly, GPS information is all that’s available to calculate attitude if no Gyro is present in your Apple device.

In both cases GPS information is critical, which means (a) a high-quality antenna is necessary, since the Apple antenna is generally not sufficient for this purpose, and (b) the GPS information must be highly precise, which can only be assured with a WAAS (Wide Area Augmentation System) or EGNOS GPS unit. The internal Apple GPS is not WAAS-capable, but all external GPS units are, and all have much improved antennas. See below for suggested external GPS models. Note that we now support the Emprum Ultimate 5 Hz GPS and other Multi-Rate GPS models. (Note: EGNOS is equivalent to WAAS in many non-US areas of the world.)

Garmin GLO Support

The new Garmin GLO bluetooth GPS unit is not currently supported by PocketHorizon Pro, so we recommend one of the other GPS choices if you’re purchasing one right now. Attempting to use the GLO at this time will result in unstable (wobbling) roll and pitch due to Garmin’s design choice of a varying position update rate. GLO support may be included in an upcoming release but is not guaranteed due to the unusual behavior of the Garmin unit. For this reason, we cannot recommend it at this time. Thank you for understanding.

(MEMS) Gyro + GPS Use

Most newer Apple devices contain an internal MEMS (Micro-Electro-Mechanical System) Gyroscope. This is a solid-state ‘chip’ gyro that is the same type used on much more expensive glass panels. PocketHorizon Pro uses this gyro to show quick Roll and Pitch changes, combining with the GPS to constantly calibrate the gyros. No user action is needed to perform this calibration.

The internal MEMS gyro is currently available in the following Apple devices: iPhone 4, 4S, 5, iPod touch 4th Gen, 5th Gen, iPad 2, 3 & 4, iPad mini.

GPS-Only Use

PocketHorizon Pro works fine with GPS-only, with slower response than Gyro units but with the same ultimate accuracy. NOTE that this is NOT the simple ‘rate of turn’ indicator you see on some GPS units; PocketHorizon Pro calculates actual bank angle based on speed, rate of turn and other factors. External WAAS GPS is even more important with GPS-only use since the GPS provides all attitude information to the display and must be highly precise.

No External GPS?

We don’t approve such use, but yes, PocketHorizon Pro will ‘work’ using only the internal GPS in your iPhone or iPad, but you will possibly, even likely, experience some instability (‘wobbling’) in roll, especially in turns. The iPhone 4 is not bad, though – it seems to have the best internal GPS of all Apple devices tested and usually works pretty well with PocketHorizon Pro, but our testing shows that the internal GPS in the iPhone 3GS is not very good at all, nor is the one in the iPad 2; these devices will almost certainly show wobbling, and they should be considered unusable without an external GPS with a good view of the sky.

Trying PocketHorizon Pro with Gyro on the Ground

You can do this, but please remember that PocketHorizon Pro is designed to only work properly in flight, and will not show the readout you might expect on the ground or in a car. This is especially true if you’re trying the Gyro on the ground by holding the device and rotating it; you’ll see it return to center after a few seconds. This is normal! It’s a function of the way PocketHorizon Pro combines Gyro and GPS to produce accurate attitude that requires no calibration. To see things work as you expect, just try it in flight. But if you still want to try it on the ground in a car we suggest selecting “Piper J3 Cub” as aircraft type since the associated speeds nearly match car speeds. AOA OFF is also suggested since cars have no angle of attack! Just be sure to reactivate AOA if desired for the next flight.

Supports iOS 5.0 or higher

If your Apple device does not have at least iOS 5.0 installed you’ll need to upgrade it using iTunes to the latest version your device supports, which is always good policy with iOS devices. Just run iTunes on your computer (PC or Mac), connect to the internet, and plug in your device. iTunes should detect that your device needs updating and allow you to do so, or you can click on your device on the left panel of iTunes and press the ‘Check for Update’ button. Note that an update can be quite large, and can take a couple of hours at DSL speeds, so be prepared for a long download.

The Smaller Apple Devices

While the iPad seems to get all the aviation press these days, we feel that pilots shouldn’t overlook the smaller Apple devices such as the iPhone and especially the iPod touch. Some of the benefits:

  • Allow use of single-purpose dedicated aviation apps in addition to the larger comprehensive app you’ll likely use with your iPad
  • Lower cost (as little as $100 for a used iPod touch 2nd or 3rd generation)
  • iPhone is connected to the cell network, giving you access to online services before the flight
  • An aviation use for your iPhone while in flight!

Universal App for iPhone, iPod touch and iPad

PocketHorizon Pro is a “Universal App” that is designed for iPhone, iPad and iPod touch. Specifically:

  • iPhone 3GS / 4 / 4S / 5 / 5S / 5C / 6 / 6+ / 6S / 6S+
  • iPad 1 / 2 / 3 / 4
  • iPad mini (all)
  • iPod touch 3 / 4 / 5

iOS 5.0 or higher is required for all devices.

PocketHorizon Pro – Over two years in development by Logical Drive, a company with 18+ years experience building certified glass cockpit software for top GA aircraft.

Don’t spend $3500 + installation for a battery-backed standby horizon, or even $1400+ for a larger, difficult to mount portable – Use PocketHorizon Pro to help keep the shiny side up!

PocketHorizon Pro – the one that really works!


  • New AirNetTM “network in the air” to connect multiple devices running PocketHorizon or PocketHorizon Pro
  • No subscription required
  • Universal app for iPad, iPhone, iPod touch devices
  • Portrait or Landscape mode for all devices
  • Quick attitude response when used with a device containing a Gyro
  • Works with or without Gyro (External GPS is required in either case)
  • Smooth 10 Hz operation, even with GPS-only
  • No calibration required
  • Screen dimming, including extra-visible sunlight colors (Hardware & Software dimming)
  • Lay-Flat mode for use with a kneeboard
  • Airplane-specific aerodynamics calculations for best attitude accuracy, with:
  • Extensive collection of predefined aircraft
  • Wizard-based aircraft editor for creation or modification of aircraft
  • Extensive Help function in-app, incl. P.O.H., FAQ, Quick Start
  • Full P.O.H. provided on this web site, plus Mounting, FAQs, Troubleshooting info and Quick Start
  • Supports Apple multitasking (keeping multiple apps running at once)

iOS Devices:

  • Can be ship-powered for running and charging
  • Long battery life when running PocketHorizon Pro, verified by Logical Drive (in the 2½ to 10 hour range, depending on device, even when powering an external GPS)

What It’s Not

PocketHorizon Pro is not for use as the sole primary attitude instrument, but as supplemental information to either confirm correct operation of your primary attitude indicator or to be used as a backup, along with information from your other instruments, only once you have determined for yourself that PocketHorizon Pro is appropriate for such backup purposes. See further disclaimers below.

While similar, PocketHorizon Pro does not provide identical information to a primary attitude indicator due to its method of deriving attitude information from indirect sources such as GPS. It is, however, quite accurate, even when using only GPS to determine attitude, and is quite sufficient for the intended use. Note that best attitude accuracy (especially in Roll) is obtained during coordinated flight – keeping the ball centered.

PocketHorizon Pro is not intended for aerobatics, and will not respond correctly to aerobatic maneuvers.

For More Information on PocketHorizon Pro

Click on the menu tabs above for more information, including a downloadable Pilot’s Operating Handbook (P.O.H.), FAQs, Support (with Troubleshooting Tips) and much more.


NOTE: PocketHorizon Pro is a GPS-assisted attitude display and REQUIRES GPS with WAAS and a good signal EVEN WHEN USED WITH THE GYRO! The internal GPS included in iPhone and many iPads will work, but an external WAAS GPS such as the Bad Elf or Dual units is required when used with all devices, especially of course those that do not include a GPS, such as the WiFi-only iPad and all iPod touch models. In any case you must have a clear view of the sky; if you don’t have such a clear view within your cockpit we recommend positioning the device above the instrument panel or near a side window, or using a separate Bluetooth GPS placed in a good sky view position. The Bad Elf GPS seems to get a high quality signal even on a kneeboard, so is a very good choice. Another good choice is a Bluetooth GPS unit such as the Dual XGPS, which can be positioned above the instrument panel as far forward as possible. Finally, we now support the Emprum UltiMate GPS and find it delivers equivalent performance to the Bad Elf, but our tests show that it does seem to use more of the device’s battery power, leading to about a 12% reduction in operating time. In many cases this won’t be significant, but should be considered. The Emprum is well made, with most significantly a locking power plug for external ship power that means it won’t be accidentally coming loose during flight.  Note that PocketHorizon Pro does NOT work with the Garmin GLO GPS.

NOTE: PocketHorizon Pro is for pilots only, is not a toy, and is optimized for use ONLY in an airplane. It doesn’t show meaningful information in an automobile, because the displayed attitude depends on the interrelationship between rate-of-turn and bank angle, and rate-of-climb and pitch angle. In a car you have ROT & ROC but no bank or pitch angle, so what you see will not be a true representation of attitude. (You will, however, be able to hold a Gyro device and demonstrate the gyro attitude action.) Bottom line: If you don’t fly an airplane please don’t buy this app!

NOTE: PocketHorizon Pro is not intended for Aerobatics, and will not respond correctly during rolls, loops or other aerobatic maneuvers as defined by the FARs. One reason for this limitation is the GPS’s role in calculating roll and pitch. While an aircraft is inverted, changes in GPS track and altitude are reversed. Since roll and pitch indications are calculated from GPS track and altitude values, when changes in those values are temporarily reversed during aerobatic maneuvers you will see opposite and incorrect roll and pitch indications.

NOTE: PocketHorizon Pro is not designed for use in a helicopter, since forward speed is necessary for correct attitude information. PocketHorizon Pro is in limited functionality mode when below a threshold airspeed, which is approximately stall speed (dirty) of a fixed-wing airplane.

DISCLAIMER: This product consists of two components, the PocketHorizon Pro software and your Apple iOS device. Neither the PocketHorizon Pro software nor the Apple device are FAA Certified, and therefore should only be used for supplemental situational awareness in cooperation with other instruments and information sources in your airplane. You alone must determine whether PocketHorizon Pro and the iOS device are appropriate for instrument backup purposes. Logical Drive Inc. does not assume any risk from your use of either PocketHorizon Pro or the iOS device, therefore you use these at your own risk. If you do not agree with these provisions you are not authorized to use the PocketHorizon Pro software, and should not purchase this app. Thank you for understanding.