Authorities → Compare In development
How does each authority define night?
Four different rule families, one word. The same wheels-up to wheels-down produces different night totals under different authorities — legitimately.
There are four distinct night-definition families in force across these fourteen authorities: civil twilight (the FAA/EASA mainstream), sunset ±20 minutes (Singapore — measured at surface level), sunset ±30 minutes (the UK family), and sunset ±1 hour (China, unconfirmed). A night total computed under one family is simply a different number under another.
| Authority | State | Night definition | Source | Status |
|---|---|---|---|---|
| FAA | United States | Civil twilight to civil twilight | 14 CFR § 1.1 | Verified |
| EASA | European Union | Civil twilight to civil twilight (a state may prescribe a sunset–sunrise variant) | SERA / FCL.010 | Verified |
| UK CAA | United Kingdom | 30 min after sunset → 30 min before sunrise | Air Navigation Order | Verified |
| QCAA | Qatar | Civil twilight, “or such other period between sunset and sunrise as may be prescribed” | QCAR-FCL; PIL.14/19 §4.2(k) | Verified |
| TCCA | Canada | Civil twilight to civil twilight | CARs | Verified |
| CASA | Australia | Civil twilight to civil twilight | CASR | Verified |
| NZCAA | New Zealand | Civil twilight (working definition — CAR Part 1 wording still being sourced) | — | Verifying |
| GCAA | United Arab Emirates | Civil twilight to civil twilight | CAR-OPS | Verified |
| HKCAD | Hong Kong | 30 min after sunset → 30 min before sunrise | CAD 371 §7.16 | Verified |
| CAAS | Singapore | 20 min after sunset → 20 min before sunrise, sunset and sunrise determined at surface level | ANO Part I para 2 | Verified |
| GACA | Saudi Arabia | Civil twilight is the working reading (FAR lineage); GACAR Part 1 not yet retrieved | — | Verifying |
| DGCA | India | Commonly cited as 30 min after sunset → 30 min before sunrise; not confirmed against the Aircraft Rules | — | Verifying |
| CAAC | China | 1 hour after sunset → 1 hour before sunrise appears in operational context; not confirmed as the defined term | — | Verifying |
| JCAB | Japan | Not confirmed in primary sources | — | Verifying |
Verified means read from the authority’s own legislation and recorded with the clause. Where we have not confirmed something, the row says so — a working reading is not a citation. See the verification state of all fourteen →
Questions
Asked and answered
Why does the same flight produce different night totals under different authorities?
Because the definitions genuinely differ. A sector that touches the window between civil twilight and 30 minutes after sunset counts night under the UK's Air Navigation Order but not under the FAA's § 1.1 — and Singapore's ANO measures its 20-minute offsets at surface level, which matters in terrain. None of the totals is wrong; they answer different questions.
Is the FAA's night the same as its night-landing currency window?
No. Night for logging runs civil twilight to civil twilight (§ 1.1); night-landing currency uses one hour after sunset to one hour before sunrise (§ 61.57(b)). Two definitions in the same regulation, for different purposes.
Can a logbook just store one night figure per flight?
Only by picking one authority's definition and silently mis-answering the others. Sojourn stores the sun and twilight timestamps for the route and computes night per authority at export — which is why the record keeps raw facts rather than a single night total.