AltitudeAlert adds vertical navigation (VNAV) feature

The last ten years have been exciting to follow as hundreds of aviation apps have been developed for aviation use in the app store. While some like ForeFlight, Garmin Pilot and FlyQ have grown to become required equipment for pilots, there are countless others that offer a more specialized feature set and are worth checking out.

One of our favorites in this category is the AltitudeAlert app. In addition to offering features not available in other EFB apps, it’s regularly updated and takes advantage of the latest multitasking screens and Apple Watch capabilities. The app is a surprisingly helpful tool, and since it works in slide-over mode on the iPad it’s easy to run side-by-side with ForeFlight or Garmin Pilot.

Here’s a quick review of the three main ways to use the app:

• ALT HOLD mode monitors your altitude and alerts you when you exceed a preselected margin (say, 50 feet). This is ideal for cruise flight – just tap the big button to set your current altitude as the preferred one and the app will send a notification if you exceed your buffer. It’s simple and a great reminder, especially if you don’t have an autopilot.
• SELECTOR mode allows you to set minimums on an approach. The app will alert you 100 feet above minimums and again at minimums, just like a glass cockpit.
• SELECTOR mode also allows you to choose an altitude for level-off, either in climb or descent. You can choose either a single alert or an alert with the altitude remaining.

The latest update to the app builds on the core altitude hold features and adds Vertical Navigation (VNAV) planning. Common in larger airplanes and those with glass cockpits, VNAV is useful for IFR pilots when given a crossing restriction during descent. It’s also useful for VFR pilots to plan a smooth descent and arrival to the destination airport.

To use the feature, first press the VNAV button to load the VNAV configuration page. Tap the “Search Published Waypoint” button and enter either the ATC-assigned crossing waypoint or destination airport, depending on how you’re using the feature. AltitudeAlert contains a database of all the waypoints and airports in the U.S. and will calculate the distance from your present position to that waypoint.

Next, tap the “Enter Altitude Constraint” to enter the desired crossing altitude. If you’re flying VFR and are planning a VFR descent to the destination airport, you’ll likely want to enter the traffic pattern altitude here. Then, tap the “Distance Offset” button to add a buffer if you’d like to have the app plan for the crossing a few miles before the selected waypoint. Again, VFR pilots may want to select 2 or 3 miles so as not to descend directly into the traffic pattern.

Finally, you can select to either select a specified descent rate in ft/min or a glidepath angle. Many GA pilots prefer to use a shallow 500 ft./min descent for comfort, while pressurized transport-category airplanes may elect to fly a standard 3° descents using the glidepath option with a faster descent rate.

After entering your preferences for the descent, press the green “Exec” button at the top right to arm the VNAV function. Approximately 1 minute from the top-of-descent (TOD) point, the app will send a notification “Approaching VNAV Descent”, to get your attention if you don’t have the app open on your iPad or iPhone.

At the bottom of the screen, you’ll see the familiar glidepath diamond to show the status of your descent along the pre-planned path. The upper and lower indices on the white indicator represent 500’ above to 500’ below the target altitude.

To get started, you can download the app free and try it for 30 days without a subscription. It then requires a subscription for either $1.49/month or $12.99/year.