✈️ NightLog Pro

EASA Part-FCL Night Time Calculator

Flight Date
Departure
Arrival
Recent Calculations
  • No calculations yet
Airport Solar Data
🛫 DEP
--
Sunrise --:--:--
Sunset --:--:--
Dawn (-6°) --:--:--
Dusk (-6°) --:--:--
🛬 ARR
--
Sunrise --:--:--
Sunset --:--:--
Dawn (-6°) --:--:--
Dusk (-6°) --:--:--
Flight Timeline
Waiting for calculation...
Night (-6°)
Twilight
Day
Solar Intercept Map
How was this calculated?
±1 min Accuracy NightLog Pro calculated your exact position once per minute to find the precise moment the sun crossed -6° at your aircraft.
Flight Manifest
Awaiting Calculation Enter flight details and calculate to view manifest.
Help & Documentation
📖 How to Use
Step 1: Enter your flight date in DD-MM-YYYY format
Step 2: Select departure airport and enter Off-Blocks time (UTC)
Step 3: Select arrival airport and enter On-Blocks time (UTC)
Step 4: Click "Calculate Night Time"

💡 Tip: All times must be in UTC. The app handles midnight crossings automatically.
🔬 Calculation Methodology
NightLog Pro uses Great Circle interpolation to calculate your exact flight path, sampling your position every 1 minute along the route.
  • SunCalc Library: Astronomical accuracy for sun position
  • -6° Threshold: Civil twilight boundary (EASA/FAA Part 61)
  • -0.83° Threshold: Sunset/sunrise boundary (FAA Part 1)
  • SLERP Algorithm: Spherical interpolation for accurate path tracking
🎓 Understanding EASA Night Time
What is "Night" according to EASA Part-FCL?
Night is defined as the period between the end of evening civil twilight and the beginning of morning civil twilight.

What is Civil Twilight?
Civil twilight occurs when the sun is 6 degrees below the horizon. At this point:
  • It's dark enough that artificial lighting is required
  • The horizon is still visible
  • This is the regulatory standard across European aviation
📝 Notes for Pilots
  • Always verify calculations with your airline's procedures
  • This tool assists with EASA Part-FCL and FAA Part 61 requirements
  • Keep your official logbook as the primary record
  • Use UTC times consistently for accurate calculations
✅ Accuracy: Results are calculated to ±1 minute precision using minute-by-minute position sampling.
💻 Browser Compatibility & Support
Supported Browsers:
  • ✅ Chrome / Edge (Recommended)
  • ✅ Firefox
  • ✅ Safari
  • ✅ Mobile browsers (iOS Safari, Chrome Mobile)
Troubleshooting:
  • Ensure internet connection for CDN libraries
  • All times must be in UTC format
  • Type at least 2 characters for airport search