Hello, and thank you for subscribing! AltitudeAlert is an advanced altitude management system for Apple mobile devices. Please take a moment to review this guide and familiarize yourself with its features.
No user guide can cover every scenario you might encounter while flying. Please feel free to reach out through the app website (altitudealertapp.com) or Facebook (facebook.com/altitudealert).
This guide applies to AltitudeAlert on both iPhone and iPad. The two apps share the same features and behavior; where something is specific to one device (for example, iPad multitasking), it is called out inline.
When AltitudeAlert launches for the first time, you will be asked to allow Notifications. Choose Allow — background alerts will not be delivered without it. After agreeing to the User Agreement, you can adjust settings or continue to the main page.
On iPad, AltitudeAlert also needs the barometric sensor (where present) for its primary Barometric Altitude Reference; no special permission is required, but see GPS Altitude Reference for devices without a baro sensor.
On iPad, AltitudeAlert runs in three configurations, in both landscape and portrait: Stand Alone, Slide Over, and Split View / Stage Manager.
The full AltitudeAlert interface occupies the entire display; all alerts are delivered through the app with corresponding audio. This is the first screen you see at launch and gives the most information about each alert.
Split View runs two apps side by side (1/3–2/3, 1/2–1/2, or 2/3–1/3). Both apps stay visible and fully functional. Setup is nearly identical to Slide Over — when you move the “elongated” app to the side, the open app slides over to make room. Drag the divider handle to change the split.
Slide Over, Split View, and Stage Manager use iPadOS multitasking. See Apple’s documentation for setting up these modes on your iPad.
iOS notifications operate separately from AltitudeAlert’s in-app aural and visual alerts. Configure them in the iOS Settings app:
The most reliable banner style is Persistent: it forces you to acknowledge the alert before it clears, which is valuable when the cockpit gets busy. Temporary also works but auto-dismisses. If you use AltitudeAlert only in the foreground, either style is fine. For Slide Over / Split View / Stage Manager, use Persistent.
To ensure iOS notification audio is audible, set the Ringer and Alerts slider to full and leave Change with Buttons OFF. With it off, the device’s volume buttons control master output only, giving the most consistent results.
If your headset is not connected to your device, you will not hear aural alerts. While not required, it is the best experience. In general, the best option is an ANR headset with Bluetooth; alternatively, connect an ANR headset via a 1/8″ stereo audio cable from the device to a headset or intercom.
There are two operating modes:
There is nothing to set up — just go fly. To monitor an altitude, tap the ALT HOLD tab and then TAP TO HOLD ALT. AltitudeAlert alerts you when you exceed the Deviation Margin shown on the page. See ALT HOLD Mode and Alert Margins.
Pressure altitude, corrected by the Altimeter Setting and rounded to the nearest 10′. Once the altimeter setting is entered, the reference altitude should match the aircraft altimeter within a few feet. Airborne, it may read slightly high due to the Venturi effect around the cockpit; a −75′ adjustment is applied automatically above 80 kts groundspeed. Any residual error can be removed with Quick Calibrate (below).
On the ground the Power button is shown. Airborne, the CX ALRTS button appears and cancels all altitude and accuracy alerts (oxygen alerts are unaffected). Atmospheric, field, and SELECTOR settings are retained. To restart alerting, select a new altitude in the SELECTOR.
Separated into thousands and hundreds of feet; selectable from 0 to 17,900′. High-altitude alerts up to 45,900′ (FL459) are available by enabling Altitude Limit 45900 in App Settings. Set the altitude with the + / − buttons or by sliding a digit up or down.
When an altitude alert is received, the text turns black and the box becomes amber, with an aural alert. When you reach the SELECTOR altitude, the box turns green.
Engages Landing Mode. The target altitude is zeroed and the display turns magenta. AltitudeAlert calls out 1000′ AGL and 500′ AGL for situational awareness, and — if Retractable Landing Gear is enabled in App Settings — “check landing gear down” after the 500′ call. Accuracy depends on the correct landing Field Elevation (see Controls).
Sets Decision Altitude (DA) or Minimum Descent Altitude (MDA) for an instrument approach. See Setting DA/MDA Minimums.
Visual and aural alerts when supplemental oxygen is required. The Pilot OXY amber light illuminates above 12,500′ MSL; PAX OXY above 15,000′ MSL. Both extinguish on descent below the respective altitudes.
Touching the Ref Alt — BARO label “quick calibrates” the reference altitude to the SELECTOR — a fast way to sync and zero any residual error against the aircraft altimeter. The calibration is retained until removed (touch the label again) or replaced. Because the device’s barometric sensor is sensitive to cockpit pressure (for example, opening or closing vents), you may need to recalibrate seasonally as temperatures change.
Access this User Guide, Manage Subscription (App Store version), the Support Website, and Adjust Settings. Test Alerting runs a ~14-second confidence test of many aural and visual alerts.
Shows the status of the loaded NAV Data. When data is missing or out of date, a Download button appears; when current, it becomes Remove NAV Data. See NAV Data Updates.
Set the current altimeter setting with the + / − buttons, the slider, or by tapping the value to open a numeric keypad. If the local altimeter setting is unavailable, tap Use Field Elev to set the altimeter from a known field elevation. Airborne, the STD button resets the altimeter setting to standard pressure (29.92″Hg / 1013 hPa). Toggle between inHg and hPa with the unit switch.
When shown, set the surface temperature to refine the reference-altitude correction. (Available on devices and configurations that use the temperature correction.)
Field Elevation is the airport elevation used as the reference for landing-mode and AGL calculations. Set the Takeoff/Landing Elevation with the + / − controls, or tap DFLT to load your saved default field elevation. The Field Controls remain available whenever you need to set or adjust the destination field elevation.
Tap DA/MDA, enter the published DA or MDA, and tap ARM. AltitudeAlert generates an alert at 100′ above minimums and again at minimums. Setting the destination Field Elevation correctly is important for accurate results.
Note: DA/MDA alerting is not available when GPS Altitude Reference is ON.
By default AltitudeAlert uses Barometric Altitude Reference (most accurate). You can switch to GPS Altitude Reference in the iOS Settings page. This is intended for a few specific cases — for example, pressurized aircraft, or devices without a barometric sensor (where it is forced ON automatically).
The first time you confirm GPS Altitude Reference, AltitudeAlert asks you to acknowledge the selection. Because GPS altitude can differ from the aircraft altimeter when atmospheric conditions aloft differ from the surface, occasionally an erroneous alert may occur; verify the altimeter setting, then use the Altitude “Quick Sync” touch zone to correct any residual error.
The AGL Proximity Alert is an independent ground-proximity callout that announces when you climb or descend through a selected height above ground level (AGL). It runs on its own — in the foreground and the background — whether or not you have started standard altitude alerting.
Open the AGL ALERT tab and turn on Enable AGL Alert. Then choose:
500′ AGL or 600′ AGL.Climb, Descent, or Both.
Climb fires once on the way up, Descent once on the way down, Both fires on each crossing.When enabled, an AGL ALERT badge appears on the tab, and an INHBT AGL button appears on the SELECTOR screen so you can momentarily inhibit the AGL callout when desired.
AGL reference sets itself, and it follows the airplane through the flight:
No manual entry is required. The AGL ALERT screen shows the current field-elevation source so you can confirm it at a glance:
Field Elev: 1234′ (GPS) — captured automatically on the ground.Field Elev: 1234′ (airport DB) — the nearest airport to your current position,
used in flight (your destination on approach).Field Elev: 1234′ (manual) — the value set in Controls, used as a fallback.not captured — taxi or hold on the ground briefly to capture it.For the destination case — when you are airborne and approaching a field — AltitudeAlert can reference a global airport elevation database so AGL works outside the U.S. as well. This database refreshes automatically alongside your NAV Data updates and is kept entirely separate from the published NAV Data used for VNAV. You can also refresh it on demand with Refresh Airport Data on the AGL ALERT tab.
When you cross the selected altitude, AltitudeAlert speaks “Five Hundred” or “Six Hundred” — in the foreground (live speech) and in the background (as a spoken notification). A banner accompanies the background callout.
You can verify the AGL alert on the ground without flying. On the AGL ALERT tab, tap Test AGL Alert. AltitudeAlert jumps to the SELECTOR screen and simulates a climb and descent through your selected altitude, showing a live readout of the simulated GPS altitude, field elevation, and AGL value. The readout flashes ALERT FIRED at the exact moment the alert triggers, and you hear the matching callout — confirming the alert is tied to the altitude data.
ALT HOLD is a simple alerter for VFR flying and training. Tap the ALT HOLD tab, then TAP TO HOLD ALT to begin monitoring your current altitude. AltitudeAlert alerts you when you exceed the Deviation Margin shown on the page. Adjust the margin to suit your flying. The app can also launch directly into ALT HOLD mode — see App Settings.
Two margins control when alerts fire; both are adjustable for your flying style.
Alert Margin 500′, Deviation Margin 200′, SELECTOR 5000′. Climbing through 4500′, the Alert Margin is reached and the altitude alert fires (single “C” chime + amber visual). After reaching 5000′, AltitudeAlert watches for deviation; if you drift below 4800′ (5000 − 200), the “check altitude” alert fires. Correcting the deviation — or selecting a new altitude — clears it.
VNAV lets you navigate vertically from one altitude to another based on conditions you define — most commonly an altitude ATC assigns over a point (a waypoint, navaid, or airport). Tap VNAV on the SELECTOR page to open the VNAV Configuration page.
CVG for the VOR, KCVG for the
airport).−10. An
asterisk (*) marks an offset waypoint, and the displayed distance is to the offset.When a waypoint, constraint, and path type are entered, the VNAV Data Display shows the data with a green EXEC? prompt. Tap EXEC? to execute and return to the SELECTOR tab with active VNAV guidance.
Three components:
OFST and an asterisk
shown when offset), VNAV Path Data (green distance to Top-of-Descent and the path type), and Aircraft
reference data: V/S (vertical speed required if you began descent now) and
V/B (vertical bearing/angle to the constraint). When V/B equals your chosen glidepath,
the VGPI is near center.On the VNAV Configuration page, tap User Defined, then enter the latitude and longitude (auto-formats as you type) and give it a unique 5-character name. The waypoint is saved for reuse. To clear all user waypoints, use Clear User Waypoint Database in App Settings.
Cruising at 10,000′ near the CVG VOR, direct MILAN, ATC issues: “cross 10 miles southeast of MILAN at 8,000 ft.”
MILAN.8000 as the Altitude Constraint.−10 (southeast of MILAN is before you reach it).500 fpm.MILAN* @ 8000′ OFST −10nm) and tap
EXEC?.About one minute from Top-of-Descent you receive an “Approaching VNAV Descent” notification; begin the descent within ~500′ of the path. Within 1 nm of the waypoint, VNAV guidance clears and resets.
VNAV is designed primarily for descents, but provides limited data for a climbing constraint: enter the altitude as you would for a descent (a path type is required to activate but is not used for the climb). V/S and V/B then show the climb rate/angle required. When the aircraft climbs more than 1 nm past the constraint, VNAV switches to descent logic.
The published NAV Database (currently U.S. coverage, included at no additional fee) powers VNAV waypoint search. Download or update it from the App Settings page or the VNAV Configuration page — AltitudeAlert notifies you when an update is available. Use a strong internet connection before downloading.
Open the iOS Settings app and select AltitudeAlert.
Default OFF. ON launches the app in ALT HOLD mode; OFF launches in SELECTOR mode.
Default OFF. When ON, AltitudeAlert uses GPS rather than the barometric sensor (see GPS Altitude Reference). On devices without a barometric sensor this is always ON. DA/MDA alerting is not available when GPS Altitude Reference is ON.
Default OFF. When ON, the alert margin is spoken after the alert chime (for example, “600 to go”).
Default ON. Announces “Altitude Acquired” each time the SELECTOR altitude is reached, and again when returning after a deviation beyond the Deviation Margin.
Default OFF. When ON, adds the “Check Landing Gear Down” aural alert when Landing Mode is engaged.
Default OFF (max selectable 17,900′). ON raises the limit to 45,900′ (FL459). The alerting algorithms are optimized for use below 18,000′; use caution above.
Shows Purchase Date and Renew Date. Subscriptions auto-renew; cancel any time in your Apple Account settings at least 24 hours before the renew date.
Current app version, build number, Terms & Conditions, Privacy Policy, and Acknowledgements.
Resets the app to factory defaults, including subscription status (you will need to Restore Purchases). Only do this if the app is behaving abnormally.
How alerts are delivered when AltitudeAlert is in the background. Visual “Alert/Banner” refers to the style chosen in iOS Settings.
| Alert | Visual (Banner) | Aural |
|---|---|---|
| Standard Altitude Alert chime | × | × |
| “Check Altitude” | × | × |
| “Altitude Acquired” | × | × |
| “Pilot Oxygen Required” | × | × |
| “Passenger Oxygen Required” | × | × |
| “Approaching VNAV Descent” | × | × |
| “1000 ft. Above Touchdown” | × | |
| “500 ft. Above Touchdown. Check Landing Gear Down” | × | |
| “500 ft. Above Touchdown” | × | |
| “Approaching Minimums” | × | |
| “Approaching Minimums. Check Landing Gear Down” | × | |
| “Minimums” | × | × |
| AGL Proximity Alert — “Five/Six Hundred” (new) | × | × |
| Pressure Sensor Failure (iPad) | × | × |
| GPS Accuracy Degradation | × | × |
| GPS Accuracy Restored | × |
If you receive an inordinate number of accuracy alerts (“ACCY LOW”, “ALT INVLD”):
Toggle GPS Altitude Reference in the iOS Settings app and return to AltitudeAlert; the change now applies on return. If the display still shows the previous reference, fully background and reopen the app.
Confirm AGL Alert is enabled, the AGL ALERT badge is showing, and a field elevation is available (the AGL ALERT screen shows the source). On the ground, taxi or hold briefly with a clear view of the sky so GPS can capture field elevation. Use Test AGL Alert to verify the alert path.
AltitudeAlert User Guide · Version 3.4