Most people picture an air ambulance as a helicopter landing on a motorway. But when a patient is hundreds or thousands of kilometres from the hospital they need, or stuck in a foreign country after an accident, the job goes to a jet. Air-ambulance jets are business aircraft rebuilt as flying intensive care units, and they cross oceans every night with a patient, a medical team and two pilots on board.

The subject was in the news this weekend after a Gulfstream G100 air ambulance disappeared south of Nantucket on a flight from Bermuda to Boston with six people on board. The cause is not yet known, and we have covered what is known in our report on the G100. Here is how these flights work in general: the aircraft, the crew, the cabin and the medicine of flying sick people at altitude.

Why Use a Jet Instead of a Helicopter

Helicopters are ideal for short distances and for landing at the scene of an accident. They are slow, though, and most are unpressurised. For long distances, the advantages of a fixed-wing aircraft take over. According to standard descriptions of the service, fixed-wing air ambulances are used to move patients over long distances and to repatriate them from foreign countries, as well as for organ transport and critical care transfers between hospitals.

A jet can cruise at well over 400 knots and above most weather. A US hospital programme, MedCenter Air, lists cruise speeds of over 420 knots for its Cessna Citation jets and over 440 knots for its Pilatus PC-24s, with cruising altitudes of 35,000 to 45,000 feet.

Pilatus shows how an air-ambulance interior is installed in the PC-24.

L'avion

Almost any pressurised business aircraft can become an air ambulance. Common types include the Learjet 35, 36, 31 and 45, the Beechcraft King Air 90 and 200, the Pilatus PC-12 and PC-24, and larger jets such as the Bombardier Challenger. Most are configured for one patient, and some can take two or more.

The conversion is mostly about the cabin. Seats are removed and replaced with a stretcher system bolted to the floor, often mounted on a base with oxygen and electrical outlets. Medical monitors and ventilators are fixed to the walls, and a wide cargo door, like the one on the PC-24, makes loading a stretcher much easier.

Who Is on Board

A typical air-ambulance jet flies with two pilots and two medical crew. MedCenter Air, for example, flies with two pilots and a medical team of two registered nurses, a nurse and a respiratory therapist, or a nurse and a paramedic. Its pilots hold airline transport pilot certificates and at least 2,000 flight hours, and its medical crew have three to five years of intensive care or emergency experience.

For the sickest patients, operators add a flight physician. Swiss Air-Rescue Rega crews its ambulance jets with flight physicians and intensive care nurses, and on long missions carries a second flight crew who can rest in bunk beds in the cabin. Aviation Week described Rega’s jets as the equivalent of high-speed, long-range airborne intensive care units.

Rega on the modern cockpits of its Challenger 650 ambulance jets.

An Intensive Care Unit in a Business Jet

The medical equipment on a modern ambulance jet can match a hospital ward. Some American programmes can carry patients on ECMO, the heart-lung support used for the most critically ill, and on cardiac assist pumps. Many can also carry newborns in transport incubators. Rega’s Challenger 650s, which have a nonstop range of about 6,500 kilometres, carry cardiovascular support equipment and specialist kits for premature babies.

Rega also developed a Patient Isolation Unit in 2015 for highly contagious patients, which it used heavily during the COVID-19 pandemic.

The Medicine of Altitude

Flying a patient is not just like driving one. Even in a pressurised cabin, the air pressure at cruising altitude is lower than on the ground, and that changes how the body and the equipment behave.

Trapped gas expands in the gut, the middle ear and the sinuses, and in medical devices such as the cuff of a breathing tube. A patient whose oxygen level is borderline on the ground can drop further in the air. That is why flight nurses and paramedics are trained in altitude physiology, and why the same guide advises keeping divers who need transport below 8,000 feet.

Long Overwater Legs

Air-ambulance jets often fly the routes that airlines do not: remote islands, small airports and long overwater sectors at night. A flight from Bermuda to Boston, like the G100’s, covers about 670 nautical miles of open Atlantic. Operators plan these legs around fuel reserves and alternate airports in the same way as any other business jet, with the added pressure that the patient cannot wait for better weather.

In the United States, the Commission on Accreditation of Medical Transport Systems, known as CAMTS, sets standards for air medical services, and many operators seek its accreditation. The work is demanding and much of it happens at night, which is why both the medical and the flight crews on these jets are among the most experienced in civil aviation.

Smithsonian Channel on the LifeMed Alaska Learjet 45 XR air ambulance.

Sources: Wikipedia, Air ambulance and Rega (air rescue); Aviation Week, “Rega To The Rescue”; Rega news release, 3 April 2020; Atrium Health MedCenter Air, Fixed-Wing Critical Care Transport; EMRA EMS Essentials, Chapter 12: Flight