What is the altitude one must reach in order to communicate with the ground? Is it possible to talk to ground via radio flying over the oceans? How to know the exact position of an aircraft over the oceans?

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    $\begingroup$ Pilots make position reports over the HF radio. HF follows the curvature of the earth unlike VHF which is line-of-sight, so altitude should not be an issue. $\endgroup$
    – Ron Beyer
    Feb 1, 2018 at 4:13

1 Answer 1


As Ron mentions in the comments aircraft flying transatlantic routes (or really any long route for that matter) may use HF radios operating in the 3-30MHz range to communicate over long distances. HF radio waves have the ability to "skip" off the ionosphere if directed properly and thus propagate over the horizon and beyond line of site.

You can find some various frequency info here.

Honeywell also offers at least one satellite based solution.

You can also find a lot of good info here under the "communication" tab.

As for knowing the exact position of the an aircraft, this answers covers most navigation methods out there.

This thread quotes FL300 (30,000 Ft.) as the minimum altitude for continuous coverage across the Atlantic as does ymb1's answer here (route dependent).

  • $\begingroup$ That is very interesting and thank you for your promptness. Those extremely high frequencies waves must still encounter some limits though. Or are we saying that wherever an aircraft might be, as long as it keep 30,000 ft, pilots can keep contact with the ground during the whole cruise? $\endgroup$ Feb 1, 2018 at 8:06
  • $\begingroup$ @cornutifelici HF (High Frequency) is 3-30 MHz, while VHF (Very High Frequency) is 30-300 MHz. HF is lower frequency (longer wavelength) than VHF. $\endgroup$
    – user
    Feb 1, 2018 at 13:08
  • $\begingroup$ Link-fix above for "communications", aopa.org/travel/international-travel/transatlantic then select Communications tab. $\endgroup$
    – javabrett
    Oct 17, 2018 at 5:17

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