In separate incidents, two medical transportation aircraft went down in Ohio and Alaska–one rotor wing and one fixed wing. In total, all six of the flight crew members involved in the incidents are presumed dead. It’s not believed either aircraft carried patients at the time of the crashes.

On Tuesday, Ohio State Highway Patrol confirmed a Bell 407 operated by Survival Flight, Inc. crashed shortly before 7: 30 a.m. while en route to pick up a patient in Pomeroy, Ohio, located about an hour’s drive southeast of Columbus. Approximately three hours after the downed aircraft report, local authorities discovered the crash site in Zaleski, an area slightly northwest of Pomeroy. According to a report from Fox Carolina, investigators from the National Transportation Safety Board (NTSB) and the Federal Aviation Administration (FAA) are currently working at the crash site.

Later that same day, the U.S. Coast Guard (USCG) launched a search for a missing King Air 200 flying from Anchorage, Alaska to the remote town of Kake. Operated by medical transportation company Guardian Flight, the crew was scheduled to pick up a patient upon arrival. The USCG is assisted by municipal fire and rescue departments as well as civilian vessels in the area, according to a report from the Navy Times. Although airplane wreckage was found about 20 miles from Kake, the USCG hasn’t confirmed whether it belongs to the missing King Air. As a precaution, Guardian Flight grounded its entire fleet until the root cause of the crash is determined.

Normally, a medical evacuation aircraft carries a crew of three: one pilot and two care providers, usually two nurses or a nurse and a paramedic. The patient care staff are often trained in emergency medicine as well as critical care, and many are experienced in aeronautical-specific medicine. Medical transportation flights are used to ferry patients quickly over long distances and often operate in remote areas.

Although these recent incidents are tragic, the industry as a whole has improved safety measures. According to flight paramedic Kitt Hunter, the industry once operated with a “cowboy attitude,” but many medical transportation companies now have stricter safety regulations than required by the FAA. Still, incidents such as these are always a severe hit for areo-medical professionals.

“The rule for us is three to go and one to say no,” said Hunter. “All it takes is one crew member to refuse the flight and the mission is canceled. We also have to submit a risk assessment for every flight to our headquarters, so that’s another pair of eyes looking at our flight plan and the weather [conditions]. Our company is working to extend the time from when the call is received to liftoff to ensure our safety. Still, anytime you hear about a flight going down you feel it in the pit of your stomach.”