Why Do Planes Disappear Over the Sea on Flight Trackers?
Aircraft disappear from flight trackers over oceans because ADS-B is a radio broadcast that needs a receiver within roughly 250 miles to be heard. Over open water there is nothing to receive it. The aircraft is tracked normally by air traffic control throughout — it is the public tracking map that has the gap, not the aviation system.
Watch a transatlantic flight on any tracking map and it will vanish somewhere west of Ireland, reappearing near Newfoundland an hour or more later. Nothing has gone wrong.
This is the most common question people ask about flight tracking, and the answer explains a lot about how the whole system works.
Why does the aircraft vanish?
ADS-B is a radio broadcast. The aircraft transmits its position continuously on 1090 MHz, and anyone with a receiver in range can hear it. That is the entire mechanism, and it is why flight tracking is available to the public at all.
Radio at that frequency travels in a straight line, so range is limited by the curvature of the earth. From a high-altitude aircraft to a ground receiver the practical maximum is roughly 250 miles in good conditions.
Over the North Atlantic there is nothing to put a receiver on for well over a thousand miles. The aircraft keeps broadcasting exactly as before. There is simply nobody there to hear it.
Is the aircraft actually untracked?
No, and this is the part worth being clear about. Air traffic control knows where it is throughout.
Oceanic control uses procedural separation, satellite communications and position reporting rather than the radar coverage used over land. Aircraft on the North Atlantic tracks report their positions at defined intervals and are separated by time and distance rather than being watched continuously on a screen.
What has a gap is the public ADS-B tracking map, not the aviation system.
Haven't satellites fixed this?
Partly. Satellite-based ADS-B receivers now exist, carried on low-earth-orbit satellite constellations, and they can hear aircraft broadcasts over oceans.
That data is real and it is used operationally — it has genuinely improved oceanic air traffic control. But it is commercially licensed and expensive, so it does not generally flow into free public tracking maps. Some paid services include it; most free ones do not.
So the gap you see on a public map is increasingly a commercial boundary rather than a technical one.
Where else do aircraft disappear?
Anywhere without ground receivers. Large deserts, central Africa, parts of Siberia, the Amazon and the polar regions all have coverage gaps for the same reason as the oceans.
Low altitude also causes it. An aircraft at 2,000 feet has a far shorter radio horizon than one at 38,000, which is why light aircraft and helicopters drop off tracking maps far more readily than airliners.
And not every aircraft carries ADS-B. Older light aircraft, some military types and gliders may not broadcast at all, and military aircraft can turn it off.
| Situation | Visible on a public tracker? | Why |
|---|---|---|
| Airliner over land | Yes | Dense ground receiver coverage |
| Airliner mid-Atlantic | Usually not | No ground receiver within range |
| Light aircraft at low level | Often not | Short radio horizon at low altitude |
| Military aircraft | Sometimes | ADS-B can be switched off |
| Glider | Often not | Many carry no ADS-B transmitter |
Where a live display fits
A home display is entirely dependent on this coverage, which is worth understanding before buying any of them. Ours shows aircraft near you, where receiver coverage is dense and the data is excellent.
It is also why the display correctly shows nothing rather than a guess when there is nothing in range — an empty sky is a real answer, and inventing an aircraft to fill it would be worse than useless.
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Quick answers
Why do planes disappear over the ocean on flight trackers? Because ADS-B is a radio broadcast that needs a ground receiver within roughly 250 miles to be heard, and there is nothing to mount one on in the middle of an ocean. The aircraft keeps transmitting normally; there is simply nobody in range to receive it.
Is a plane over the Atlantic actually being tracked? Yes. Air traffic control uses procedural separation, satellite communication and position reporting over oceans rather than continuous radar. The gap is in the public tracking map, not in the aviation system — controllers know where the aircraft is throughout.
Do satellites track planes over oceans? Yes, satellite-based ADS-B receivers exist and have genuinely improved oceanic air traffic control. However the data is commercially licensed and expensive, so most free public tracking maps do not include it. The gap you see is increasingly commercial rather than technical.
Why do small planes disappear from flight trackers? Two reasons. An aircraft at low altitude has a much shorter radio horizon than an airliner at 38,000 feet, so its broadcast reaches far fewer receivers. And many older light aircraft and gliders carry no ADS-B transmitter at all.
How far away can ADS-B be received? Roughly 250 miles in good conditions from a high-altitude aircraft to a ground receiver. The limit is the curvature of the earth — the signal travels in a straight line, so range depends heavily on the aircraft's altitude.