EGJB – Guernsey Airport
Tier B (estimated) · 147 movements in 2026 · NM-inferred milestones, no capture metrics
Coverage here is judged on estimated reference times. What can be said firmly is whether flights were seen at all: 93.3% of movements in 2026 are picked up. Across its departures, essentially none of the taxi-out reached the network: this aerodrome is invisible on the ground even though its flights are seen in the air. There is no arrival figure, so this page carries no coverage index.
| period | departures | arrivals | Departures seen (%) | Arrivals seen (%) | Coverage index |
|---|---|---|---|---|---|
| 2026 | 75 | 72 | 93.3% | 95.8% | — |
| 2025 | 83 | 74 | 98.8% | 97.3% | — |
| 2024 | 75 | 79 | 82.7% | 84.8% | — |
Departures
off_s is good when negative – the track began before take-off.
When the track starts, relative to take-off (minutes)
| period | n | p10 | p50 | p90 |
|---|---|---|---|---|
| 2026 | 70 | -0.1 | +0.3 | +0.8 |
| 2025 | 82 | -7.7 | -3.3 | +0.7 |
| 2024 | 62 | -0.2 | +0.9 | +1.5 |
| delta 2026-2025 | +7.6 | +3.6 | +0.0 |
Arrivals
land_s is good when positive – the track ran on past landing.
When the track ends, relative to landing (minutes)
| period | n | p10 | p50 | p90 |
|---|---|---|---|---|
| 2026 | 69 | +6.4 | +8.5 | +12.3 |
| 2025 | 72 | +2.9 | +8.5 | +24.8 |
| 2024 | 67 | +1.6 | +4.7 | +6.1 |
| delta 2026-2025 | +3.5 | +0.1 | -12.5 |
Where the coverage is
Each position report is placed on a hexagonal grid over the aerodrome, on a log colour scale: one apron cell can hold thousands of reports while a runway threshold holds tens. Empty ground is surface the receivers do not reach.
Use the legend to add the airborne layer and any example flights. Scroll to zoom.
Example flights are shown only where a movement’s ground phase can be bounded, so its coverage can be ranked. No movement here has one.
The tier decides what can be measured.
Tier A (measured by APDF). The airport’s own records give the real times: off-block, take-off, landing, in-block. The taxi has exact bounds, so how much of it arrived is a measurement.
Tier B (estimated by NM). Network Manager gives an off-block time and a predicted taxi duration – an estimate, not a measured one. With no runway times, take-off is inferred, so only a median across a few hundred movements is worth reading.
There is no in-block time either, so nothing ends a taxi-in; NM’s arrival time is off-block plus predicted taxi plus predicted flight duration, adding nothing. Tier B therefore gets no arrival coverage, and the coverage index needs both sides.
The all-aerodromes table holds both, its taxi-out column filled throughout and asterisked where the window was measured.
Against the fleet
How this aerodrome compares with the aerodromes with estimated milestones. Typical aerodrome is the median across all of them. Rank is this aerodrome’s position among them, 0 (lowest) to 100 (highest).
| measure | this aerodrome | typical aerodrome | rank (0–100) |
|---|---|---|---|
| Departures seen (%) | 93.3% | 99.8% | 16 |
| Arrivals seen (%) | 95.8% | 99.7% | 20 |
| Track start vs take-off (min, median) | +0.3 | +1.0 | 32 |
| Track end vs landing (min, median) | +8.5 | +4.0 | 82 |
Higher rank is better everywhere except track start vs take-off, where a low value is the good case.
Was each flight tracked as one flight?
A poor coverage number can mean the receivers heard nothing, or that the algorithm cut the flight’s track up. This separates them.
| period | One flight, one track (%) | Split across tracks (%) | Merged with another flight (%) |
|---|---|---|---|
| 2026 departures | 80.0% | 5.3% | 8.0% |
| 2026 arrivals | 83.3% | 2.8% | 9.7% |
| 2025 departures | 91.6% | 0.0% | 7.2% |
| 2025 arrivals | 86.5% | 0.0% | 10.8% |
| 2024 departures | 82.7% | 0.0% | 0.0% |
| 2024 arrivals | 81.0% | 3.8% | 0.0% |
The underlying counts
Everything above is derived from these. Typical taxi times are context: the same 200 seconds of reception is most of a short taxi and a fraction of a long one.
| period | Departures | Departures seen | Arrivals | Arrivals seen | Unusable reference rows | Typical taxi-out (min) | Typical taxi-in (min) |
|---|---|---|---|---|---|---|---|
| 2026 | 75 | 70 | 72 | 69 | 0 | 10.0 | — |
| 2025 | 83 | 82 | 74 | 72 | 0 | 10.0 | — |
| 2024 | 75 | 62 | 79 | 67 | 0 | 10.0 | — |