SkyCharts

_{CYYZ Airport Ground Chart — offline LIDO chart viewing with a color-coded, collapsible chart browser.}

SkyCharts brings an offline aviation-chart library to jailbroken iPads running iOS 6. The native UIKit application presents Microsoft Flight Simulator 2024 LIDO charts in a compact, Jeppesen-inspired interface designed for both portrait and landscape use.

For flight simulation only. SkyCharts and its chart content must not be used for real-world navigation.

SkyCharts provides:

• Offline airport, arrival, departure, approach, taxi, and miscellaneous charts.
• Airport selection by four-character ICAO code.
• Five compact chart categories: STAR, SID, APP, TAXI, and MISC.
• Runway-grouped procedure lists and a collapsible chart sidebar.
• Pinch-to-zoom, panning, automatic centering, and orientation-aware chart fitting.
• Interactive offline airport maps with physically proportioned runways and aviation markings, repeated collision-aware taxiway identifiers, labelled terminals, aprons, gates, and parking stands.
• A viewport-sized, display-linked label layer that tracks the map continuously during pan and pinch gestures, keeps runway designators and Terminal X identifiers at readable screen-relative sizes, and uses progressive LOD fades and density limits for taxiway, gate, and stand labels.
• Touch inspection of airport-map features with ICAO references and available surface details.
• Current METAR weather in raw and decoded views.
• In-app combined chart-and-map downloads through a Mac on the same network.
• A geographic content manager with per-level storage usage and swipe-to-delete.
• A reusable Mac cache and single-stream TAR transfers for large offline libraries.

The app does not contain an Xbox login, planner cookie, relay, or web browser. A Mac downloads authorized chart assets from the planner and matching airport geometry from OpenStreetMap, the X-Plane Scenery Gateway, or a runway-only OurAirports fallback, then bundles both into one local pack and transfers it to the iPad. SkyCharts reads the complete package from /var/mobile/Library/SkyCharts/ChartPacks; legacy maps in /var/mobile/Library/SkyCharts/AirportMaps remain supported. Version 0.8 automatically migrates packs and preferences from an existing AtlasSix installation.

The earlier relay/ service remains as an optional compatibility prototype; it is not required for the offline workflow.

User guide

1. Prepare the Mac companion

Complete the first-time setup, then launch the interactive client:

git clone https://github.com/skylarkning/SkyCharts.git
cd SkyCharts
./tools/skycharts

Choose 1. Sign in / refresh planner authentication and complete the normal Microsoft/Xbox sign-in in the browser window. The client stores the planner session privately under work/; never publish or commit that authentication file.

Choose 2. Start Pack Agent for the iPad, accept port 8770, and leave the client running while the iPad downloads content. Only one Pack Agent can use a port at a time. If the client reports Address already in use, stop the existing agent with Control-C before starting another.

2. Download charts from the iPad

Tap the gear button in SkyCharts and choose one of these options:

• Download by Country — enter a two-letter ISO 3166-1 code such as CA, US, CN, or JP.
• Download by ICAO Code — enter one or more four-character airport codes separated by commas, such as CYVR,CYYZ.

When prompted for the agent address, enter http://MAC-LAN-IP:8770, replacing MAC-LAN-IP with the Mac's address on the local network. SkyCharts displays build percentage, installation percentage, file count, and estimated remaining time. Every requested airport pack includes its charts and interactive airport map; there is no separate map download. Keep the Mac agent running until the app reports that the package is installed.

3. Select an airport

Tap the airport button at the upper-left corner, enter a downloaded ICAO code, and tap Select. SkyCharts loads the airport's available chart categories and remembers the selection for the next launch.

If the app reports that an airport is not installed, download its country or request that ICAO code from the gear menu.

4. Browse and view charts

Use the vertical category selector on the left:

• STAR — arrival procedures.
• SID — departure procedures.
• APP — instrument approach charts.
• TAXI — airport, ground, parking, and taxi charts.
• MISC — remaining provider charts and airport information.

Tap a category to display its chart list, then tap a chart name to open it. Procedures with runway metadata are grouped beneath runway headers. Tap the currently selected category again to slide the chart list away and give the chart the full viewing area; tap it once more to reopen the list.

Use two fingers to zoom and one finger to pan. Charts automatically refit and recenter after loading, rotating the iPad, or collapsing the list.

5. Open an interactive airport map

Select an installed airport and tap MAP beside the gear button. The compact offline vector map was installed with that airport's charts and does not require the Mac Pack Agent to remain running.

Drag to pan, pinch to zoom, or tap Fit to show the entire airport. Runway geometry is merged into complete full-length surfaces and uses the source runway width to draw proportional pavement, edge lines, thresholds, centerlines, touchdown markings, and aiming points. Runway designator badges remain a fixed readable size instead of enlarging with the underlying map. Named taxiway identifiers are sampled along the complete polyline and repeated at a consistent screen-space interval, including routes split into multiple source segments. The display-linked label layer follows the geometry during the gesture itself; progressively more taxiway, stand, and gate labels fade in as detail increases, while available Terminal X names remain visible at every zoom level. Grey taxiway pavement retains its natural map scale, while the independent yellow vector centerline adjusts continuously to maintain a fine screen-relative weight. Off-screen label geometry is culled and projected coordinates are cached to keep legacy iPads responsive. Tap a runway, taxiway, parking stand, gate, apron, or terminal to inspect its available reference, name, and surface details.

The first stage is a north-up airport diagram; it does not yet display ownship position, routing, traffic, or NOTAMs. Map detail depends on the best airport geometry available from OpenStreetMap or the X-Plane Scenery Gateway. Gateway DSF-text terminal facades are rendered as terminal footprints, but they remain unlabelled unless OpenStreetMap supplies a real terminal designator; the Gateway export does not reliably preserve names such as Terminal 1. Generic X-Plane New Taxiway pavement polygons are excluded so they cannot cover the airport with a grey background. Taxi-route geometry supplies the normal grey taxi pavement and yellow centerline, while explicitly named apron/ramp polygons may still be retained. The final OurAirports fallback supplies a correctly positioned runway diagram when neither detailed source has an airport layout.

6. Check METAR weather

Tap Wx at the bottom-left. The weather window provides Raw and Decoded METAR views for the selected airport. Tap the refresh button to request the latest available observation. Weather requires an Internet connection even though installed charts work offline.

7. Manage downloaded content

Open the gear menu and choose Manage Downloaded Content. Expand the hierarchy:

Continent → Country/Region → State/Province/Region → City → Airport

Each level shows its unique chart and airport-map storage. The summary at the top shows total SkyCharts storage and free space remaining on the iPad. Swipe an airport, city, subdivision, country/region, or continent to delete all offline content beneath that level. Multi-airport packs are rewritten safely so unrelated airports remain installed.

8. View application information

Open the gear menu and choose About SkyCharts to see the installed version, build number, developer credit, copyright, and project disclaimer.

Latest screenshots

The screenshots below show the current V1.0 Beta (Build 40) interface on an iPad running iOS 6.

Approach chart browser — runway-grouped procedures use cyan IAC type stripes, compact metadata, and a clear selected-chart indicator.	Expanded STAR chart — hide the chart list to devote the main viewing area to a full procedure chart.
Settings and downloads — request combined chart-and-map packs by country/region or ICAO code, manage installed content, and open application information.	METAR weather — view the latest observation in raw or decoded form without leaving the selected chart.
Downloaded content — browse the geographic hierarchy, review per-level storage usage, and remove content at any level.	About SkyCharts — the application icon, public version, internal build number, developer credit, and simulation-only disclaimer.

Repository layout

SkyCharts/                Objective-C UIKit application
SkyCharts.plist           iOS application property list
Makefile and control      Theos armv7/iOS 6 build configuration
tools/                    Mac downloader, cache, pack agent, and CLI
relay/                    Optional authenticated planner relay prototype
docs/screenshots/         Application screenshots used by this README
work/                     Cookies, jobs, cache, and generated packs (ignored)
outputs/                  Local build artifacts (ignored)

Requirements

On the Mac:

• macOS with Xcode command-line tools
• Homebrew, used by the guided environment repair option
• Theos, with THEOS pointing to its installation directory
• Theos-compatible iOS 6 SDK and armv7 toolchain
• Python 3
• A signed-in Microsoft Flight Simulator planner account
• Same-LAN access to the iPad for Pack Agent transfers

On the iPad:

• Jailbroken iPad running iOS 6
• SSH access as root
• Its LAN address, for example 192.168.2.19

The downloader requires planner authentication. The Mac client opens a dedicated Chromium window, lets the user complete the normal Microsoft/Xbox login, detects the planner's ApiToken, and saves the Cookie header privately. Treat the saved file as a password: never commit or publish it.

First-time setup

git clone https://github.com/skylarkning/SkyCharts.git
cd SkyCharts
export THEOS="$HOME/theos"
chmod 700 tools/skycharts tools/*.py
mkdir -p work
chmod 700 work
./tools/skycharts

On first launch, choose Check / repair the Mac environment. The audit reports Python, Make, Git, curl, SSH/SCP, sshpass, browser-login readiness, Xcode command-line tools, Theos, and the available iPhoneOS SDKs. Its repair options can install missing command-line tools with Homebrew and create the isolated Playwright/Chromium environment after confirmation. Theos and an iOS SDK are reported but remain deliberate manual installations.

Choose Sign in / refresh planner authentication. Complete the Microsoft/Xbox login in the browser window; the client automatically writes work/msfs-cookie.txt with mode 0600. Its persistent browser profile is stored under ignored work/ data, so later refreshes normally reuse the existing Microsoft session.

The browser flow can also be run directly:

python3 tools/skycharts_auth.py

If browser automation cannot be installed, the previous manual Cookie-header method remains a fallback: put the complete header value on one line in work/msfs-cookie.txt and run chmod 600 work/msfs-cookie.txt.

Validate the session without downloading a chart:

MSFS_COOKIE_FILE="$PWD/work/msfs-cookie.txt"
curl -sS -o /dev/null \
  -w 'HTTP %{http_code} — %{content_type}\n' \
  -H "Cookie: $(<"$MSFS_COOKIE_FILE")" \
  https://planner.flightsimulator.com/api/v1/token/expiry

HTTP 200 means the session is accepted. Renew the browser session and replace the file after a 401/403.

Build the iOS 6 package

export THEOS="$HOME/theos"
make clean package

The package is written to packages/. To keep a convenient local copy:

mkdir -p outputs
cp packages/com.skyning.skycharts_*_iphoneos-arm.deb \
  outputs/SkyCharts-ios6-armv7.deb

The Makefile targets iphone:clang:10.3:6.0 and armv7.

Version identities and DEB releases

SkyCharts deliberately keeps its public and internal versions separate:

• SkyChartsPublicVersion is the user-facing release label shown on the About page. Change it only when a new public version is explicitly requested.
• CFBundleShortVersionString is the internal iteration version. It may advance during development without changing the public release label.
• CFBundleVersion is the monotonically increasing internal build number.

The current identities are public V1.0 Beta, internal 0.15.7, and build 42. The About page therefore displays V1.0 Beta (Build 42).

SkyCharts is distributed only as a Debian package for jailbroken iPads. A final release build is created with:

export THEOS="$HOME/theos"
make clean package FINALPACKAGE=1

Copy the generated package to the release-artifact directory:

cp packages/com.skyning.skycharts_0.15.7_iphoneos-arm.deb \
  outputs/SkyCharts-0.15.7-ios6-armv7.deb

The DEB installs SkyCharts as /Applications/SkyCharts.app, preserving direct access to /var/mobile/Library/SkyCharts, existing offline packs, preferences, and local Pack Agent transfers.

Install, restart, and refresh SpringBoard

The iPad uses an old SSH server, so modern OpenSSH needs RSA compatibility flags:

IP=192.168.2.19
DEB=outputs/SkyCharts-0.15.7-ios6-armv7.deb

scp -O -o StrictHostKeyChecking=no \
  -o UserKnownHostsFile=/dev/null \
  -o HostKeyAlgorithms=+ssh-rsa \
  -o KexAlgorithms=+diffie-hellman-group14-sha1 \
  "$DEB" root@$IP:/tmp/SkyCharts.deb

ssh -o StrictHostKeyChecking=no \
  -o UserKnownHostsFile=/dev/null \
  -o HostKeyAlgorithms=+ssh-rsa \
  -o KexAlgorithms=+diffie-hellman-group14-sha1 \
  root@$IP 'dpkg -i /tmp/SkyCharts.deb'

The default password on many test jailbreaks is alpine; change it on a real device.

Restart the app:

ssh -o HostKeyAlgorithms=+ssh-rsa -o KexAlgorithms=+diffie-hellman-group14-sha1 \
  root@$IP 'killall SkyCharts 2>/dev/null || true'

Refresh the icon cache:

ssh -o HostKeyAlgorithms=+ssh-rsa -o KexAlgorithms=+diffie-hellman-group14-sha1 \
  root@$IP 'su mobile -c /usr/bin/uicache'

If old jailbreaks report cannot open cache file. incorrect user?, run the cache refresh as mobile and respring:

ssh -o HostKeyAlgorithms=+ssh-rsa -o KexAlgorithms=+diffie-hellman-group14-sha1 \
  root@$IP 'su mobile -c /usr/bin/uicache'
ssh -o HostKeyAlgorithms=+ssh-rsa -o KexAlgorithms=+diffie-hellman-group14-sha1 \
  root@$IP 'killall SpringBoard 2>/dev/null || true'

Build an offline chart pack

The downloader keeps reusable chart assets in work/chart-cache and reusable vector maps in work/airport-map-cache. Rebuilding a pack reuses both caches and hard-links chart pages into new output when possible. Light chart assets are downloaded by default. Each exported pack contains both its charts and maps/ICAO.json vector-map assets.

Selected airports:

python3 tools/skycharts_downloader.py airport KJFK KLGA \
  --cookie-file work/msfs-cookie.txt \
  --pack-id new-york-demo --name "New York Demo" \
  --output outputs/new-york-demo --workers 8

Country pack:

python3 tools/skycharts_downloader.py country CA \
  --cookie-file work/msfs-cookie.txt \
  --pack-id canada --name "Canada" \
  --output outputs/canada --workers 8

Useful options are --limit 10 for a trial, --workers 16 for more concurrency, --cache-dir PATH to relocate the reusable cache, --refresh-airports to refresh the OurAirports index, --types all to include every airport type, and --include-dark when dark PNG assets are explicitly needed.

Install an existing pack directly over SSH:

python3 tools/skycharts_downloader.py install \
  outputs/new-york-demo --host 192.168.2.19

The installer stages into a temporary directory, validates pack.json, and atomically moves the pack into ChartPacks. Failed transfers remove partial files.

Interactive Mac client

./tools/skycharts

The menu handles browser authentication, starts the Pack Agent, builds combined chart-and-map country or selected-airport packs, installs packs over SSH, installs SkyCharts DEB updates, audits the Mac environment, and reports both cache types.

• Choose Install a SkyCharts DEB package on an iPad for a guided update. It asks for the iPad IP address, DEB path, and root password; supplies all legacy RSA/key-exchange options; preserves recoverable SkyCharts data; runs dpkg; refreshes uicache as mobile; and restarts SpringBoard.
• Choose Check / repair the Mac environment to audit required commands. Homebrew repairs and the Playwright/Chromium setup are separate, confirmed actions; the audit itself never changes the Mac.
• Choose Manage cached airport packages to search by airport ICAO or name, inspect combined chart/page/map counts and storage, delete both reusable chart and map data for selected airports, remove unidentified legacy entries, or clear the complete reusable cache. Shared chart GUIDs are retained while an unselected airport still references them.

The DEB installer is also available without the menu:

./tools/skycharts install-deb outputs/SkyCharts-0.15.7-ios6-armv7.deb \
  --host 192.168.2.19

Both managers remove reusable cache entries only; exported packs, Pack Agent jobs, and content already installed on the iPad remain intact. Because chart pages may be hard-linked into an existing pack or Pack Agent job, the logical cache size removed can be larger than the immediately reclaimed disk space. If no cookie file exists, authenticated operations automatically offer browser login.

The pack builder writes a compact normalized JSON map into every airport entry and uses this source order:

1. Reuse a fresh normalized map from work/airport-map-cache.
2. Request detailed aviation geometry from a currently operating OpenStreetMap Overpass instance. Country builds briefly queue for an endpoint already serving another SkyCharts worker, so normal concurrency does not cause an unnecessary source switch. OSM terminal buildings are read from both ways and multipolygon relations; split outer rings are reconstructed so airports such as CYYZ retain every terminal footprint.
3. If OpenStreetMap is unavailable or lacks usable taxiway/stand detail, download the airport's recommended scenery from the official X-Plane Scenery Gateway and convert its embedded apt.dat runways, taxi routes, gates, ramp starts, named aprons, and DSF-text terminal facades. Airport-wide generic pavement polygons are filtered out. The terminal importer keeps ground-level footprints near gates, ignores stacked upper-level/roof/detail facades, and recognizes the generic modern/classic airport facades used by older Gateway scenery. This prevents fragmented terminal-kit layers while recovering airports whose terminal does not use the newer terminal-kit names. When both detailed sources work, SkyCharts keeps the more complete result and retains useful OSM terminal/hangar geometry.
4. If neither detailed source has a layout, create a runway-only map from OurAirports.

X-Plane itself does not need to be installed. Gateway scenery is requested per ICAO code and the converted result is stored in SkyCharts' normal reusable cache. Failed public services enter a short process-wide cooldown, while an airport confirmed to have no geometry receives a temporary negative-cache marker. A busy Overpass endpoint is allowed up to 25 seconds to finish its current airport before fallback selection. This keeps a large country build from changing sources only because all endpoints were momentarily occupied, while still avoiding repeated feature requests and long timeouts during a real outage. OSM caches created before multipolygon terminal support and Gateway caches created before ground-footprint filtering are refreshed automatically; manual cache deletion is not required. The map cache manager ignores negative-cache markers and removes the corresponding marker whenever that airport's cached package is deleted.

Global building-footprint datasets such as Overture Maps and Microsoft's Global ML Building Footprints can provide additional outlines, but they do not reliably identify which footprint is an airport terminal. SkyCharts therefore does not automatically guess terminals from those datasets; a wrong terminal polygon is more harmful than a clearly absent one. They remain possible future opt-in geometry sources for airports where both OSM and Gateway lack suitable terminal scenery.

No additional Python package is required; ZIP and apt.dat conversion use the Python standard library. The iPad footer reports the source embedded in each map. Only identifiers present in source data are labelled; unnumbered parking-position geometry remains visible without an invented stand number. OpenStreetMap data is available under the Open Database License. X-Plane Gateway data is used as a personal offline fallback and should be reviewed against the Gateway terms before distributing generated map assets.

In-app downloads through Pack Agent

Start the LAN agent:

python3 tools/skycharts_pack_agent.py \
  --cookie-file work/msfs-cookie.txt --host 0.0.0.0 --port 8770

Check it from the Mac:

curl http://127.0.0.1:8770/health

After upgrading the tools, stop any currently running agent with Control-C and start it again so Python loads the new protocol. The health response should include "transfer":"ustar-v1".

In SkyCharts, open the gear menu, choose a download option, and enter http://MAC-LAN-IP:8770. The app can request a country or comma-separated ICAO codes and polls the job. A completed job is packaged as one uncompressed USTAR stream; the app extracts that single HTTP transfer directly to temporary storage with bounded memory, validates pack.json, and atomically activates the pack. Extraction writes incoming bytes directly to file descriptors, reuses already-created directories, and validates the manifest against the in-memory extraction index instead of performing one filesystem lookup per chart. This avoids thousands of serial PNG requests and substantially reduces installation overhead on legacy iPads. Keep the agent running until installation completes. SkyCharts retains the older per-file protocol only as a fallback for an agent that has not yet been restarted or upgraded.

While a pack is being built, the footer shows overall completion percentage and an estimated remaining time. The estimate uses elapsed time plus global airport/chart progress and becomes more accurate after the first few charts complete. During the subsequent iPad transfer, the footer switches to file count, transfer percentage, and a separate transfer ETA.

Large installations are parsed incrementally from 512-byte TAR headers and written directly to their destination files. Each network callback uses a short-lived autorelease pool, no complete archive or PNG collection is retained in memory, and files are activated only after the transfer and manifest pass validation. Internal @@SKYCHARTS_PROGRESS telemetry is enabled only for Pack Agent subprocesses and is hidden from normal Mac-client output.

Chart categories

Provider categories are normalized into five compact Jeppesen-style sections:

STAR        STAR, STARPT, arrival procedure types
SID         SID, SIDPT, departure procedure types
APP         IAC and approach procedure types
TAXI        AGC, APC, AFC, LVC, ADC, APT
MISC        Any remaining provider type, including AOI

The five controls sit inside a long dark vertical pill with protected space above STAR and below MISC, so the active orange selector remains fully visible at both ends. Tapping the selected category hides or reveals the chart list with a smooth leftward slide and fade while the chart viewer resizes. Every chart row carries a color-coded vertical stripe labeled with its exact LIDO type, including SID, SIDPT, STAR, STARPT, IAC, AGC, APC, AFC, LVC, MRC, and AOI. Within a section, runway charts are grouped under headers such as RWY 10L and RWY 19R; charts without runway metadata appear under GENERAL.

Downloaded content is managed entirely through a collapsible location hierarchy: continent → ISO 3166-1 country/region → ISO 3166-2 state/province/region → city → airport. Every row reports the unique installed chart size beneath that branch. A storage summary above the hierarchy shows total SkyCharts disk usage and currently available iPad space. Swipe any level to delete all matching charts; airport- and city-level deletion rewrites multi-airport manifests and removes only assets no longer referenced, while an emptied package directory is removed automatically.

The app includes iOS 6 icon assets at 57, 72, 114, and 144 pixels, generated from SkyCharts/Resources/SkyChartsIcon-1024.png with transparent outer corners and prerendered artwork.

METAR weather

The beveled Wx button at the bottom of the category rail matches the airport selector and opens a compact iOS 6 weather window for the selected airport. It offers Raw and Decoded views plus manual refresh. Weather is read directly from the latest worldwide station files published by the U.S. National Weather Service over anonymous FTP, avoiding modern HTTPS requirements that iOS 6 cannot satisfy.

The Settings menu includes About SkyCharts, an iOS 6-style page showing the app logo, installed version and build, developer credit, copyright, and project disclaimer.

Optional legacy relay

The relay is for troubleshooting and API experiments only:

cd relay
chmod 600 ../work/msfs-cookie.txt
MSFS_COOKIE_FILE=../work/msfs-cookie.txt python3 msfs_chart_relay.py

See relay/README.md for endpoints. Never commit cookies, signed URLs, or logs containing request headers.

Troubleshooting

• 401/403 from planner: choose Sign in / refresh planner authentication in ./tools/skycharts.
• Browser login dependency missing: run python3 -m venv .venv, .venv/bin/python3 -m pip install playwright, and .venv/bin/python3 -m playwright install chromium. The launcher automatically uses this isolated environment.
• Weather unavailable: confirm the iPad has Internet access. Some airports do not publish METAR reports, and the NWS station may temporarily be unavailable.
• Pack build failed: inspect terminal output and work/pack-agent/*.log; check cookie, Internet access, and planner availability.
• Errno 61 while building maps: this means the remote TCP connection was refused, not that SkyCharts received a normal HTTP rate-limit response. Restart the Pack Agent after updating so it loads the current Overpass list, circuit breaker, and X-Plane fallback. HTTP rate limiting is normally reported explicitly as 429 Too Many Requests.
• Pack transfer failed: verify the iPad and Mac are on the same LAN, port 8770 is reachable, and iPad storage is available. Cached assets make retries faster.
• uicache cache-file error: run it as mobile and respring SpringBoard using the commands above.
• Missing chart: use the gear menu's content manager to confirm the pack and airport are installed; rebuild if pack.json references missing PNGs.

GitHub backup

Generated credentials, packs, caches, build products, and Python bytecode are excluded by .gitignore. Create the first local commit:

git init
git add .
git status
git commit -m "Initial SkyCharts iOS 6 offline chart viewer"

The canonical repository is skylarkning/SkyCharts. Add its URL and push:

git branch -M main
git remote add origin git@github.com:skylarkning/SkyCharts.git
git push -u origin main

HTTPS alternative:

git remote add origin https://github.com/skylarkning/SkyCharts.git
git push -u origin main

Verify future backups with:

git status
git log --oneline --decorate -5
git remote -v

Responsible use

Chart data comes from the Microsoft Flight Simulator planner and its provider. Access, caching, redistribution, and validity are governed by the applicable account and provider terms. Download only data you are authorized to use and do not publish cookies, signed URLs, or restricted chart packs.