Approach —

Navigate to the IAF?
Direct to

DCT flies a direct leg from where you are now. Or enter an inbound course in °TRUE (e.g. 275) to fly a fixed line into the airport, like an OBS course.

VFR route planner

Plan a route avoiding controlled airspace at your current altitude.

Avoids: CTR, TMA, CTA, Class A–D, Restricted, Danger, Prohibited.
Airspace
Type
Class
Floor
Ceiling
Frequency
Activity
Setup
Offline data — pre-flight check & download

There is no internet in flight. Before departure, while online, tap Download / update for this flight and wait until it finishes. The check below looks at what is actually stored on this device; it never marks NOTAMs or weather as verified.

Checking stored data…

    TERRAIN TO DOWNLOAD

    The download refreshes airports, approaches and airspace if the server has newer data, then airspace for every country along the route and area, then the terrain packs. It can be cancelled and resumes where it stopped. A new pack only replaces the previous one once it is complete, so an interrupted or failed update keeps the last good data. Detailed terrain worldwide is not practical (zoom 9 would be about 50 GB), so it is downloaded for an area and the route; elsewhere only the coarse world layer exists and terrain alerts say so. Ground that is not stored is shown as NO TERRAIN DATA, never as sea level.

    MOUNTING
    HORIZON SMOOTHING
    CDI FULL SCALE (2 DOTS)
    AIRPORT, APPROACH & AIRSPACE DATA

    Loading…

    One download refreshes the airport list, the approach data (runway thresholds and elevations, ILS/LOC/glideslope) that the ILS picker, GS/GP and IAF heights are computed from, and every downloaded airspace country. All are then stored on this device for offline use. Once every 28-day AIRAC cycle, when online, the app checks (a few KB) whether the server has newer data and downloads only what changed; if you are flying an approach it waits and shows an Update banner instead. Terrain is downloaded separately in Offline data above. Airport data (OurAirports) and airspace (openAIP) are community data without an official validity period; approach data validity is shown per source in the offline check.

    DEMO VERTICAL ACCURACY

    GS/GP needles need the GPS to report ±20 ft or better vertically. Otherwise the PFD shows GS UNRELIABLE and only lateral guidance remains.

    DEMO HEIGHT

    Profile flies the approach glidepath (or a ~2000 ft cruise). A fixed height holds level so you can see 3D airspace from below, inside and above.

    Volumes at your height are brighter. The face between you and an airspace above or below is lightly shaded, and walls beyond 4000 ft are cut off (the label keeps the published limit). Flight levels are drawn as altitude (no QNH correction). AGL limits use the terrain under the airspace or the destination elevation; without either, they are drawn dashed with ≈ limits. Limits the data doesn't define clearly are not drawn and are counted as UNKNOWN. NOTAM? marks conditional airspace: its activation is not checked against live NOTAMs. Without attitude, a GPS fix, GPS height or track, nothing is drawn and the reason is shown. AH full in the controls makes it full screen. Advisory only — not for navigation or airspace avoidance.

    TERRAIN PROXIMITY & ALERTS

    With TERR on, ground within 1000 ft below your GPS height turns from its height colour to amber, and red within 100 ft below or above you. The flight path is projected 60 s ahead along track at the current ground and vertical speed: TERRAIN (amber, “Caution, terrain”) when it would pass less than 500 ft above the ground, and PULL UP (red, “Terrain, terrain, pull up”, repeating) when within 30 s it would come within 100 ft. The required clearance tapers off within 5 NM of the destination runways so a normal approach doesn't alert; there are no alerts below 40 kt. Uses GPS height and the same terrain tiles as TERR (so alerts need TERR on), but only detailed tiles (zoom 9, ~95 m, or finer): over coarse-only or missing terrain there are no terrain alerts and the PFD says so (COARSE TERRAIN · NO TERRAIN ALERTS, ALERTS: NO DATA AHEAD). On iPhone, sound works after your first tap, at media volume. Advisory only — not a certified TAWS.

    AIRSPACE ENTRY ALERTS (openAIP)

    The app projects your GPS track, GPS height and vertical speed up to 6.5 NM ahead and finds where that path would first cross into an airspace, through its side, floor or ceiling. It warns once at 5 NM and once at 2 NM before that point. Airspace behind you, alongside, or clear above or below your path gives no alert. Near a floor or ceiling (±200 ft plus the GPS height error, +500 ft for flight levels, which are compared without QNH) it says POSSIBLE ENTRY. Limits it can't read give a LIMITS UNKNOWN alert rather than none. The frequency shown is the one the data publishes for that airspace. If there is none, the alert says FREQUENCY NOT IN DATA, and it never borrows another airspace's frequency. It is not a clearance and doesn't tell you to change frequency. NOTAM? airspace is alerted even when hidden on the map, because its activation is not checked. Alerts use the actual GPS height, never the map's height slider. They need ≥ 30 kt and a fresh GPS fix with height; otherwise they pause and say why. They work offline only where the airspace country has been downloaded. Terrain and minimums callouts always speak first. Advisory only — not certified, not for navigation or airspace avoidance.

    DI MAP & AIRSPACE (openAIP)

    No airspace downloaded yet.

    Height rule: an airspace is shown while your height is inside its vertical limits. A higher shelf only appears once you are within 200 ft below its floor (GPS height ≥ floor − 200 ft); airspace whose ceiling is below you is hidden. Use the height slider on the map's left edge to preview another height; GPS goes back to following your GPS height. Flight levels are treated as altitude (no QNH correction); AGL limits use the destination elevation when within 30 NM, else terrain if downloaded.

    Frequencies are shown only when the openAIP data has one for that airspace — none are invented. Countries are downloaded near you and along your route (about 0.1–5 MB each) and kept for offline use; the pre-flight download fetches every country the route and area touch. Airspace, navaids and VFR reporting points © openAIP contributors, CC BY-NC 4.0 (no IFR RNAV fixes). Road-free relief drawn on the phone from Mapterhorn elevation tiles (© Mapterhorn & sources); airports from OurAirports and cities from Natural Earth (public domain). Offline, the map is detailed inside the downloaded area and route corridor; elsewhere it falls back to the coarse world relief if that was downloaded. Not for navigation — always check the current AIP / chart and NOTAMs.

    LEVEL CALIBRATION

    USER WAYPOINTS

      AH And DI App v. Not an approved instrument — situational awareness only. Courses are TRUE. Speed is GPS ground speed; height is GPS altitude, not barometric.

      ILS / GPS GP (advisory only): the ILS button picks the approach at the active airport. AUTO prefers the most headwind from the METAR (cached offline), otherwise the runway best aligned with your GPS track. ILS and LOC use published localiser course, glideslope angle and antenna positions (FAA NASR for the US, public domain; elsewhere Robin A. Peel nav.dat 2013.10, GPL v2, so it may be out of date). They show green. Runways with no published ILS get a magenta GPS GP: a 3.0° geometric path crossing the threshold at 50 ft (OurAirports runway data), never labelled ILS. Glide path angle: with an approach selected, − / + in the controls change the angle in exact 0.1° steps (2.5–4.5°, wider only to include a steeper published angle). It starts at the approach's published GS angle, or 3.0° where none is published, for every newly selected approach. A changed angle is an advisory CUSTOM geometric path from the threshold at 50 ft: it moves the GP needle, path height and calculated IAF height, shows magenta as GP (never GS), and on an ILS reads "LOC … · GP x.x° CUSTOM" — the published glideslope itself is not changed. Use restores the default. Needles are computed from phone GPS position and GPS altitude, not from a radio receiver. LOC full scale is the ±350 ft course width at the threshold (1–3°); GS/GP full scale (2 dots) is ±0.7°, and "ON GS/GP" shows within ±0.12°. The display arms inside 15 NM and ±35° of the course, captures within 12 NM and ±3°, and shows the vertical needle inside 10 NM. Never use for an actual approach.

      Wind on the DI: surface wind at the active airport from its latest METAR (filled arrow on the compass rim, at the bearing the wind is coming from, pointing in toward the centre). A dashed arrow shows the TAF forecast wind. Directions are °TRUE, speeds in knots. Weather refreshes every 10 minutes while online, and the last report is kept for offline use with its age shown. Data from NOAA via metars.eu (fallback datamask.org). Not for operational briefing; always get an official weather brief.

      Before you fly
      1. Install it. In Safari tap Share → Add to Home Screen, then launch AH & DI from your Home Screen for a full-screen cockpit.
      2. Allow motion. Tap Enable sensors below. When iOS asks to access Motion & Orientation, tap Allow. iOS may ask again each time the app starts — tap Tap to start AHRS when you see it.
      3. Allow location with Precise ON. Choose Allow While Using App and make sure the Precise switch on the iOS prompt is on. Position, ground track, GS, GPS altitude, vertical speed, the CDI and the distance all come from the device's GPS. With Precise off iOS only gives a position to within a few kilometres, so the CDI and distance would be wrong. iPad: only Wi-Fi + Cellular iPads have a GPS chip. A Wi-Fi-only iPad needs a Bluetooth GPS receiver (e.g. Bad Elf, Dual) paired in iPadOS Settings; Safari then uses it automatically.
      4. Mount and level. Fix the iPhone or iPad upright in a panel/yoke mount, screen facing you, in portrait or landscape (or choose Flat in Setup). In level flight press LEVEL; each orientation keeps its own level.
      Denied a permission by mistake?

      Motion: close the app fully and reopen it. If it still won't ask, go to Settings → Apps → Safari → Advanced → Website Data, delete this site, then reopen. (On older iOS: Settings → Safari → Motion & Orientation Access.)

      Location / Precise Location: Settings → Privacy & Security → Location Services → turn on, then Safari Websites → While Using the App and switch Precise Location on. Then close and reopen AH & DI.

      Not certified for navigation. Phone attitude is gravity-referenced and can read wings-level in a sustained coordinated turn. Always fly by your aircraft's primary instruments.