🪂 FlyBrief NOTAMs

What is FlyBrief?

FlyBrief is a daily UK NOTAM briefing system that I built to solve a frustration: standard NOTAM feeds aimed at GA pilots are full of noise — runway closures, ILS outages, taxiway works — none of which matters to a paraglider. What matters to us is active danger areas, BVLOS drone corridors, kite flying at 3,000ft, parachute drops, military exercises, lasers, and tethered balloons.

FlyBrief takes the official UK NOTAM XML feed from NATS, strips out everything irrelevant to free flight, colour-codes the remainder by hazard type, and delivers it as an OpenAir airspace file ready to load into Oudie, SkyDemon, FlySkyHigh, or XCTrack. For XCTrack users, FlyBrief generates a dedicated XContest-format file with full NOTAM headers that enables XCTrack to auto-activate zones at their scheduled times. It also hosts an interactive map and dedicated ATZ Status page where you can generate a personalised ATZ file for your instrument, showing which ATZs have ATC on frequency and which have no radio watch — with tap-to-call phone numbers for every aerodrome.

⚠️ Not an official aviation briefing service. Always verify with official sources. Fly safe.

How it works

Eight output files

How FlyBrief generates its files

FlyBrief runs three processing scripts on the NATS NOTAM XML feed:

• convert_notams_fsh.py — generates the standard OpenAir files for Oudie, FlySkyHigh and SkyDemon. Labels each zone with a human-readable name (e.g. 06/04@2000 Parachute Drop). ATZs are not included in this file — they are handled separately via the ATZ Status page.
• convert_notams_oudie.py — generates the Oudie-format files. Uses the same filtering as convert_notams_fsh.py but with Oudie-specific output formatting. ATZs are not included in this file — they are handled separately via the ATZ Status page.
• convert_notams_xctrack.py — generates the XContest-format files for XCTrack. Uses identical filtering but outputs full * en: NOTAM headers (Q/A/B/C/D/E/F/G fields) that allow XCTrack to parse activation schedules and auto-activate zones at the correct time. ATZs are not included in this file — they are handled separately via the ATZ Status page.

Both scripts share a common filtering module (notam_filter.py) to guarantee identical NOTAM selection. The geometry (centre coordinates, radius, polygon boundaries, upper/lower ceilings) is extracted from the authoritative NOTAM body text, not the XML search coordinates, ensuring the airspace boundaries are as accurate as possible.

Files are regenerated automatically at 05:00, 10:00 and 15:00 UTC daily, and whenever a user taps Regenerate NOTAMs now on the main page.

Automated quality checking

After every regeneration, FlyBrief automatically runs a quality checker (notam_checker.py) that:

• Checks for aerodrome noise NOTAMs that may have slipped through the filter
• Compares the FlyBrief and XCTrack output files to verify they contain the same NOTAMs
• Checks that all matching NOTAMs have identical centre coordinates, radius, ceiling, floor and polygon point counts
• Emails the administrator if any discrepancies are found

OpenAir format

The output uses standard OpenAir format, which is the most widely supported airspace format for free-flight instruments. Each NOTAM becomes an airspace zone with:

• A short label for the instrument screen in the format DD/MM@HHMM Type — e.g. 30/04@2300 Tempo Danger Area or 01/04 0900-1600 Tempo Reserved Area for same-day NOTAMs
• A full description hidden in a comment line — used by the map for popup details
• Altitude limits (upper and lower)
• Geometry — either a polygon (DP points) or a circle (centre + radius)
• Colour tag (SB) for instruments that support it
• Airspace class: AC R (Restricted) for TDAs and activated danger areas (live firing, fast jets, Llanbedr etc) — triggers louder alarms on Oudie than AC Q
• Arc boundaries — NOTAMs defined with circular arc segments (e.g. the Fairford TMZ) are tessellated into smooth polygon points rather than rendered as straight-sided shapes

Times and dates

All times displayed by FlyBrief are in local UK time — BST (British Summer Time, UTC+1) from the last Sunday in March to the last Sunday in October, and GMT the rest of the year. FlyBrief automatically applies the correct offset based on the NOTAM date, so there is no need to manually add or subtract an hour.

The instrument label format is DD/MM@HHMM Type — for example 30/04@2300 Tempo Danger Area. The time shown is the expiry of the NOTAM, i.e. when it stops being active. This is not the start time.

For short-duration NOTAMs active within a single day (such as a temporary Class D for an airshow or a parachute display), FlyBrief shows both start and end times — e.g. 01/04 0900-1600 Tempo Reserved Area.

* Active: 0900-1800 BST
AC R
AN 30/04@2300 Tempo Danger Area
* Desc: J413 [30/04 @ 23:00 BST]: TEMPO DANGER AREA...
SB 255,140,0
AH 900FT AMSL
AL GND
V X=52:24:29.00 N 001:30:37.00 W
DC 2

Colour coding

Every NOTAM is colour-coded by hazard type. This appears both on instruments that support SB tags (Oudie renders these) and on the interactive map.

ATZ Status & Custom ATZ Files

FlyBrief includes a full ATZ Status page showing the radio status of all UK military ATZs today and tomorrow (🔴 ATC on frequency / ⛔ No radio comms), with NOTAM-aware status detection and tap-to-call phone numbers. All civil ATZs are also included in the custom file. The page generates a personalised ATZ file for your instrument with a radio pilot option for licensed VHF radio holders.

ATZ entry rules for paragliding pilots

Paragliding pilots without a licensed aviation VHF radio must not enter any ATZ without prior permission from the aerodrome. ATZs remain active airspace regardless of published hours. Brize Norton, Fairford and Northolt are Class D ATZs within permanent Class D controlled airspace — paragliding pilots cannot enter these under any circumstances and they are locked in the custom ATZ file.

The published hours shown on the ATZ Status page indicate when ATC services are normally staffed — they are provided as context for contacting the aerodrome, not as an indication that entry is permitted outside those hours.

The ATZ Status page generates a personalised ATZ file separate from the NOTAM files. By default all ATZs are ticked and written as AC D (proximity alarm). Pilots with prior permission to enter specific ATZs can untick them — unticked ATZs are written as AC G (FlySkyHigh/Oudie) or AC Q (XCTrack) — visible boundary, no alarm. This affects your instrument alarm only — it does not indicate whether entry is permitted.

Custom ATZ file generator

The ATZ Status page generates a personalised ATZ file for your instrument. Your instrument is pre-set from the main page — no need to re-select. All ATZs are ticked by default — all ticked ATZs are written as AC D in your custom ATZ file. If you choose to change the default, do not untick an ATZ unless you have prior permission from the aerodrome to enter or fly through it. A warning is shown when you untick any ATZ. The Generate button creates both today's and tomorrow's custom ATZ files in one go — two download buttons appear so you can grab either day. The file contains:

• Military ATZs:
  • All ticked ATZs → AC D (red, proximity alarm on instrument) regardless of published hours
  • Unticked ATZs (where you have prior permission) → AC G for FSH/Oudie, AC Q for XCTrack (visible boundary, no alarm)
• Civil ATZs (75 from Asselect) — always included as AC D. No hours data available for civil ATZs.
• Geometry — correct heights, radii and polygon shapes from the Asselect cache
• Brize Norton and Northolt — AIP fallback geometry (absorbed into CTRs in Asselect)

Airspace class reference

* Oudie only supports AC classes A–G; AC R is not available on Oudie, so AC D is used instead.

Radio pilots also get NOTAM status labels appended to each ATZ name in the file — for example NEWCASTLE ATZ [NOTAM: CLOSED] or LOSSIEMOUTH ATZ [NOTAM: DEACTIVATED]. This lets you see at a glance on your instrument which ATZs have an active NOTAM. Labels reflect the status for the day selected (Today or Tomorrow).

After generating, click 🗺 View on Map to visualise your selection — Military, Civil, or All toggle buttons. Ticked ATZs appear red (AC D — proximity alarm) and unticked ATZs appear blue (AC G/AC Q — visible boundary, no alarm). Then click Go to Build My Airspace to merge with FlyBrief NOTAMs, Asselect base airspace, and train stations into one combined file. All military ATZs are automatically stripped from the Asselect file — FlyBrief provides them with the correct AC D/AC G or AC Q status depending on your instrument. Your instrument selection is pre-set from the main page across all three pages.

The generator uses browser-based tokenisation: a unique session token is stored in localStorage alongside the pilot's ATZ selection. Selections persist across visits without requiring any login.

What gets filtered out

The most important thing FlyBrief does is remove the noise. A standard UK NOTAM briefing for a given day contains hundreds of entries — the vast majority are irrelevant to free-flight pilots. FlyBrief removes:

What always stays in

Regardless of altitude, military low-flying exercises (LFA, MIL EXER) are always kept — fast jets operating non-segregated affect all altitudes. FIGHTER CTL and HIGH ENERGY MANOEUVR zones are kept only when their upper limit is at or below FL150, making them relevant to higher-altitude sites.

Configurable settings

Two parameters can be adjusted on the web page before regenerating:

• Max lower limit (FL) — default FL110. Lower to FL85 to also filter out glider wave areas. Raise if you fly high-altitude sites.
• Large radius flag (NM) — default 20NM. NOTAMs with a circle radius above this value are flagged in the warnings file for manual review.

How does it compare to XContest?

XContest publishes a NOTAM feed widely used by paraglider and hang glider pilots. In tests comparing the same day's data, FlyBrief consistently provides more complete coverage for free-flight hazards:

Technical setup

FlyBrief runs on a Synology DS918+ NAS using:

• Python 3 (built-in on DSM) for NOTAM processing
• PHP 8.2 (Web Station) for the web interface
• nginx (built into DSM) serving on port 9090
• DSM Reverse Proxy routing flybrief.synology.me → port 9090
• Let's Encrypt certificate via DSM for HTTPS
• Leaflet.js + OpenStreetMap for the map (no API key required)

Source code

Accessing FlyBrief

The system is available to other UK pilots at:

What to load on a flying day

The FlyBrief map is ideal for a full pre-flight overview. For your instrument, load the high priority file — uk_notams_high_priority_today_YYYYMMDD.txt. This contains AC R (TDAs, activated danger areas, live firing, BVLOS), AC Q (dangerous advisory: UAS, parachutes, flares), and AC TMZ (tempo transponder mandatory zones). Merge with your custom ATZ file via Build My Airspace for the complete picture.

ATZ Status page

Check the ATZ Status page before any cross-country flight. It shows all UK military ATZs with direct phone numbers and published hours, plus all civil ATZs. Generate a personalised custom ATZ file — untick only ATZs where you have prior permission to enter. If you hold a licensed aviation VHF radio, tick the radio option to get AC R for military ATZs and NOTAM status labels in zone names. ATZs are not in the NOTAM files — they are handled via the ATZ Status page.

Loading into your instrument

• Oudie / SeeYou Mobile: Settings → Active Collections → Add Airspace File.
• FlySkyHigh: Share button to open in FlySkyHigh. Airspace settings → Custom (FlyBrief only) or Both (combined with built-in airspace).
• SkyDemon: Manage Airspace → Custom OpenAir → import.
• XCTrack: Settings → Airspace → import OpenAir file. Use the XCTrack format file for auto-activation support.
• XCSoar: Settings → Site Files → Airspace.

Map

Use the View map link on the main page for a visual overview of today's NOTAMs. Tap any zone for full details — name, altitude limits, AC class, and active schedule in local time. The 📍 My location button centres the map on your GPS position — useful on mobile after landing out.

The map has an 📋 NOTAMs panel listing all active airspace zones as scrollable cards. On desktop it auto-opens after a short delay, defaulting to Today. Use the tabs to switch between Today, Today HP, Tomorrow, and Tomorrow HP — the map and cards update together. Clicking a category filter button (Danger, TDA, UAS, Balloon, TMZ, etc.) filters both the map and the cards to match. On mobile, tap the button to open the panel as a bottom sheet.

The ATZ map view has a dedicated 📋 ATZ NOTAMs panel showing any ATZs with an active NOTAM (closed, deactivated, activated, or hours change). Cards are grouped into Military and Civil tabs. Tap any card to zoom the map to that aerodrome. On desktop the panel auto-opens and highlights the matching card when you click an ATZ circle. On mobile it rises as a bottom sheet and closes after you select a card.

CTA altitude colour banding (online map only)

On merged file maps, CTA sectors (Bristol, Cardiff, etc.) are colour-coded by their lower altitude limit so the stepped inner boundaries are clearly visible:

• 🔴 1500ft — red (innermost, lowest base)
• 🟠 2000ft — orange
• 🟡 2500ft — amber
• 🟢 3000ft — green
• 🔵 3500ft–4000ft — blue
• 🟣 5000ft+ — purple (outermost, highest base)

ℹ️ This colour banding is purely a visual aid on the FlyBrief online map for pre-flight planning. It does not affect your instrument file — Asselect data is always passed through to your instrument unchanged.

Accurate airspace geometry (online map only)

All OpenAir arcs (V D=± direction + DB arcs) on the online map are now tessellated with high-resolution geodesic arcs (48 steps) matching the official AIP geometry. A previous JavaScript parser bug in the map viewer affected how 81 UK zones were drawn on the FlyBrief online map — Bristol, Birmingham, Newcastle, Cardiff, Edinburgh and most major CTAs plus LoA areas Bath Gap and Ubley. Arcs were occasionally drawn going the wrong way around their centre, making boundaries appear in the wrong place.

ℹ️ This bug only affected the online map display. Instrument files (FSH / Oudie / XCTrack) have always used the correct raw Asselect geometry — the bug was purely in the FlyBrief JavaScript map viewer. Credit to Tim Pentreath for spotting the issue.

🪂 Event briefing maps

FlyBrief supports event-specific airspace briefing maps for competitions, aerotow events, fly-ins and XC meets. Event organisers can share a single link that shows a map centred on the venue, with a radius circle (typically 100km), filtered to show only NOTAMs and airspace within that radius. A popup with the event name, dates, site, description and optional logo opens automatically on page load.

Event maps are created via URL parameters (?event=...¢re=lat,lon&radius=100&dates=...&desc=...&logo=...) or via short-link IDs in the events registry (e.g. e.php?id=gbar2026). Let Steve know if your club runs an event that could benefit from a dedicated briefing link.

Train stations on the map

The map shows all 2,563 UK train stations as coloured dots using live timetable data:

• Green — station has services today
• Amber — closed today but has services tomorrow
• Red — no service today or tomorrow

Tap any station dot to see live departure times — first and last train, next departure, all upcoming services, and a direct National Rail link. Useful for planning a retrieval route after landing out.

XCTrack widget

The FlyBrief map can be used as a live XCTrack widget — a moving map showing today's NOTAMs, train stations, and your GPS position, embedded directly in XCTrack during flight.

Suggested URL:

Key parameters: zoom=8 (regional view), location=on (centres on GPS), ui=off (hides toolbar for clean widget), trains=on (shows station dots), bigzoom=on (larger zoom buttons for gloved hands). Full parameter reference in the Quick Start Guide.

UK paragliding sites

The map shows all UK paragliding sites sourced from paraglidingearth.com via a 24-hour cached proxy. Tap any site marker for the site name and a direct link to its paraglidingearth.com page. Useful for identifying flyable sites near your landing area.

Build My Airspace

The Build My Airspace tool combines multiple sources into a single download. Select your instrument first — the page adjusts to show only relevant NOTAM files and train station options.

Sources available

• FlyBrief NOTAMs — today's or tomorrow's full or high priority file. ATZs are not included — add your custom ATZ file separately below. Optional.
• Tim's Asselect file — UK permanent airspace fetched automatically from Google Drive. The ⓘ button shows Tim's exact settings, altitude overlay, airfield types, and local agreements (Bath Gap, Dunstable, Westbury, Halesland and others). Direct download also available. Or upload your own from asselect.uk.
• Custom ATZ file — if a custom ATZ file has been generated on the ATZ Status page, a checkbox appears. The Generate button creates both today's and tomorrow's ATZ files in one go — the correct day is automatically merged based on your NOTAM selection. When included alongside any Asselect file (Tim's cached version or your own upload), all ATZs are automatically stripped from the Asselect — both military and civil — to eliminate duplicates. Your custom ATZ file provides all ATZs with correct radio status and your permission selections.
• Train stations — FlySkyHigh/XCTrack: bow markers in the combined file (today's or tomorrow's train times). Oudie: .cup waypoints file downloaded separately.
• Club Local Agreements (LoAs) — opt-in section listing UK paragliding/hang gliding LoAs (Bath Gap, Halesland, Ubley, Westbury, Dunstable). Tick only the LoAs you have permission to use. Ticked LoAs change the matching airspace from AC D/R (proximity alarm) to AC G (visible boundary, no alarm). Selections reset every page load — pilots must consciously tick each session. Each LoA includes a 📄 doc link to the official agreement.
  
  Dunstable (HG/PG) is handled with enhanced geometry. When ticked, FlyBrief strips the aggregated Dunstable zone and the overlapping Luton CTR blocks from Tim's Asselect, and appends a detailed set of zones derived from the DHPC Airspace Brief: CRSA (SFC–1500ft), CRSA Extension (SFC–2500ft), LGC exclusion zones (Green/Yellow/Orange Areas + Bottom Landings) to prevent overflying club operations, Whipsnade Zoo (no landing SFC–1500ft), and a carved Luton CTR that excludes CRSA at the appropriate altitudes. This geometry was contributed by Will Rice (former DHPC Technical Officer) and matches the official NATS↔LGC↔DHPC↔RAFGSA LoA and the DHPC Airspace Brief. A ✍️ sign-in link takes pilots directly to the DHPC Airspace Sign-in form — required before flying Area 1.
• Uploaded files — any additional OpenAir .txt file; validated for OpenAir content, 5 MB limit.

Merge confirmation

After building, a confirmation banner shows exactly what was merged — e.g. "Today's NOTAMs + Today's custom ATZ + Asselect + Train stations" — so you can verify the contents before downloading. The ATZ day automatically follows the NOTAM file selection: if you select tomorrow's NOTAMs, tomorrow's custom ATZ is merged to match.

Automatic filtering on merge

All Asselect and uploaded files are automatically filtered before merging: temporary zones already covered by FlyBrief NOTAMs (Fairford TMZ, Coningsby RA(T), Odiham RA(T), Silverstone RA(T) and others) are stripped; zones labelled (NOTAM) are removed; zones with a floor at FL110 or above are removed. Merged files are stored on the server for one hour then auto-deleted.

Regenerating

If the files look stale, use the Regenerate NOTAMs now button to run the script immediately.