Sea Level Flight
Most aircraft — including many air ambulances — hold a cabin pressure equivalent to 6,000–8,000 ft of altitude, which reduces available oxygen and can change the volume of gas trapped in the body. For certain patients, even a moderate cabin altitude can be dangerous or medically contraindicated. Ambulance Flight can configure select aircraft to maintain cabin pressure at or near sea level throughout the flight, keeping oxygenation and gas volumes stable, as they would be on the ground.
Who this service is for
- Patients who have had recent chest, abdominal, ENT, or eye surgery involving trapped air or gas.
- Divers or patients with confirmed or suspected decompression sickness or arterial gas embolism.
- Patients with pneumothorax (treated or untreated) where a cabin altitude change is contraindicated.
- Patients with severe respiratory or cardiac conditions whose treating physician requires a sea-level cabin environment.
What's included
- Aircraft selected and configured specifically for sea-level (or near-sea-level) cabin pressurization capability.
- Continuous cabin altitude monitoring throughout the flight, coordinated with the medical crew.
- Medical crew briefed on the specific pressure-sensitive condition before departure.
- Coordination with the referring physician or hyperbaric/dive-medicine specialist when relevant.
- Flight planning — altitude and routing — built around the patient's pressure tolerance, not just distance and speed.
Cabin altitude, explained
Aircraft cabins are pressurised. Regulations allow a cabin pressure equivalent to an altitude of up to 8,000 ft, and most aircraft sit between 6,000 and 8,000 ft at cruising altitude. At that pressure, gas trapped in the body takes up roughly 35% more volume than at sea level, and the oxygen available to the blood is lower.
For most travellers this makes no difference. For a patient with air or gas trapped in the chest or tissues, or with nitrogen bubbles after a dive, it can matter a great deal. This is why a physician may require a cabin held at, or very close to, sea level.
Conditions that may call for a sea-level cabin
The following list is general information, not medical advice. Whether a sea-level cabin is needed, and to what altitude, is always decided by the treating physician, together with our coordinating physician.
- Recent surgery with trapped gas: chest, abdominal, ENT or eye surgery.
- Pneumothorax: air in the pleural space does not expand in a sea-level cabin.
- Decompression illness after diving: published recommendations for transporting these patients advise keeping the cabin altitude as close to ground level as possible, typically no more than about 500 ft above the departure point.
- Other cases in which the physician specifies a maximum cabin altitude.
What a sea-level cabin means for the flight plan
Every pressurised aircraft has a maximum pressure difference between the cabin and the outside air. To keep the cabin at sea level, the aircraft has to fly lower than it normally would: as an indication, roughly between 20,000 and 25,000 ft depending on the model, instead of 40,000 ft and above.
Flying lower has practical consequences that we plan for from the start:
- More fuel is burned and the range is shorter, so a long route may need one or more technical stops.
- The flight can take longer, and the aircraft is more exposed to weather and turbulence.
- Not every aircraft can do it. We select the aircraft after the medical assessment and tell you early on if the route requires a stop.
If the physician asks for a different target, for example a cabin altitude below a given number of feet, the flight plan is adapted accordingly.
Further reading
Sources : Interfacility transport of patients with decompression illness: literature review and consensus statement (PubMed) · EMS Flight Barotrauma (StatPearls, NCBI Bookshelf) · Cabin pressurization (reference article)
How it works
Medical assessment
Your case, your physician's notes and the specific pressure sensitivity are reviewed before any aircraft is selected.
Aircraft & crew selection
We select an aircraft capable of maintaining a sea-level (or physician-specified) cabin altitude for the full route, and brief the flight crew and medical team accordingly.
Continuous monitoring in flight
Cabin altitude and patient vitals are monitored throughout the mission, with the flight plan adjusted if needed.
Handover
On arrival, a full report — including the cabin pressure log — is provided to the receiving medical team.
Common questions
It means the aircraft cabin is pressurized to maintain an altitude at or near sea level (0 ft) throughout the flight, instead of the 6,000–8,000 ft cabin altitude typical of most aircraft — which matters for patients whose condition is sensitive to changes in pressure or oxygen availability.
Common cases include recent chest, abdominal, ENT or eye surgery involving trapped gas, pneumothorax, decompression sickness in divers, and some severe respiratory or cardiac conditions — always confirmed with the treating physician before the mission is planned.
No — it requires an aircraft specifically capable of it and a flight plan built around that constraint. We select the aircraft and route for each mission based on the patient's medical requirement, not the other way around.
It can: the aircraft flies lower, burns more fuel and may need an additional stop. We do not publish a fixed price. The quote is built after the medical assessment and itemises what drives the cost.
The treating physician. Our coordinating physician reviews the file with the hospital and confirms what the flight plan has to achieve before an aircraft is chosen.
Decompression illness is a medical emergency, handled first by local diving-medicine services. When a transfer is considered, published recommendations advise keeping the cabin altitude as close to ground level as possible. Call us as soon as the treating team considers a transfer and we coordinate with them.
Often, yes: lower altitudes mean higher fuel consumption and sometimes a technical stop. We tell you what to expect once the route and the aircraft are known.
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