What is a sea-level medical flight?

Serious medical conditions can make it difficult for patients to receive permission to fly – even if that flight is designed to take them to a hospital for urgent treatment. Transporting a patient with brain trauma, a collapsed lung or anaemia, for example, may be risky on a regular, high-altitude flight.


But does that mean there’s no chance of securing a medical transport abroad? Not necessarily. Circumstances depending, we may be able to organise a low-altitude, “sea-level flight” for your patient. Here’s what you need to know.

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How high do planes normally fly?

Most commercial jets fly at a cruising height of between 28,000ftand 38,000ft (8.5-11.5km) – typically around 35,000ft (10.5km). Private jets tend to fly a little higher, from 41,000ft to 45,000ft (12.5-13.7km). This atmospheric zone is known as the troposphere, and there are several good reasons why it’s considered to be a “sweet spot” for international flights. For one thing, there’s less turbulence at these altitudes. There are also fewer potential hazards, such as birds. And the thinner air creates less drag on the aircraft, which means the plane is more fuel-efficient.

What’s the problem with altitude?

Flying high above ground level has some physical implications for our bodies. If you’ve ever heard climbers talk about summitting Everest (29,031ft / 8,848m), you’ll know they sometimes carry oxygen with them. This is because air pressure and density decrease with altitude, meaning the body is able to take in less oxygen the higher you go. To compensate for this, jet cabins are pressurized. But the pressure is still higher than at ground level – on most commercial planes it’s equivalent to about 8,000ft (2.4km). Pressure changes also causes gases in the body to expand. For healthy people, this is rarely a problem. But it can be an issue for some patients with serious medical issues.

What kinds of patients might be affected?

Air ambulanceHigh-altitude flying can cause problems for people with certain lung and brain conditions, or who have had various kinds of major surgery. If you’ve suffered a serious head injury, for instance, pressurization could potentially lead to a damaging increase in pressure within the cranial cavity. Other conditions with a higher risk factor include:

  • Collapsed lung (pneumothorax)
  • Air accumulation in the eye socket
  • Abdominal obstructions
  • Brain swelling (cerebral oedema)
  • Bleeding on the brain (haematoma)
  • Anaemia (lack of red blood cells)
  • Recent surgical wounds

How does a sea-level flight work?

If the local doctors say your patient isn’t “fit to fly” – i.e. they feel it would be unsafe, or too risky, for them to fly at high altitude – we can think about other potential options for the transport. We can precision-regulate the pressure on some of our intensive-care air ambulances and on certain kinds of private jet. But if these options aren’t suitable either, then we may be able to arrange for your patient to “fly sea level” instead.


A sea-level flight simply means the aircraft – which will usually be one of our ICU-equipped private jets– has been given clearance to travel well below the normal flying altitude. This isn’t sea level itself (for obvious reasons!) but lower than the usual height, to avoid the increasing air pressure of higher altitudes. It provides a pressure environment for the patient that’s closer to ground-level conditions.

How would EMS Air Ambulance & Medical Repatriation arrange one of these flights?

If we think a sea-level flight might be possible, we’ll discuss it in detail with your local doctors. Our repatriation experts will then contact the aviation authorities to secure a low-altitude permit. We can also mobilise very quickly in emergency ICU situations if we need to – often within hours of your call.


We’ll make sure the right medical specialists are able to travel with your patient on the flight, and that we’re carrying all the emergency equipment, oxygen canisters and medication they might need in transit. Intensive-care air ambulances are equipped to deliver just that – ICU-level treatment if it ever becomes necessary during the transport. When the choice is between keeping your patient where they are and flying them to the hospital or medical team of your own choosing, that can mean a world of difference.

Contact us

If you're worried about whether or not you can fly a loved one abroad for treatment, please get in touch with our team and they’ll be glad to advise you. Even in very difficult situations, there’s almost always something we can do to help. Please drop the EMS team a line, day or night, by phone, WhatsApp or email: you’ll find all the details on our Contacts page.

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