Three people including two Mayo Clinic workers were killed in a Mayo Clinic helicopter crash in Florida on Monday. The causes and names of the victims are still unknown, but the accident will likely increase the already growing scrutiny on medical helicopters.

It’s been an intense 18 months for the profession. Medical helicopters were labeled as flying the “most dangerous missions in aviation” and the “most dangerous profession in America” in a July 2010 article in Popular Mechanics. Some states were using helicopters unnecessarily, the article found, and they have fewer equipment requirements and poorer protocols – around things as pedestrian as weather checks – than other kinds of flights.

Several North Carolina medical facilities operate medical helicopters, including Duke University Medical Center, UNC Hospitals, WakeMed, Pitt County Memorial Hospital, Wake Forest Baptist Medical Center and Carolinas Medical Center in Charlotte.

Part of the reason for the dangers were from an early era in air ambulances. As of mid-2010, the fatal accident rate on medical helicopters was 1.18 per 100,000 hours. Meanwhile, the rate for all general aviation and air taxi flights is 1.13 per 100, 000 hours, according to the Federal Aviation Administration. For helicopters specifically, the rate can vary between 1 and 1.94 per 100,000 hours.

But there remains a consensus that, in general, medical helicopters are not safe enough. The National Transportation Safety Board earlier this year said current helicopter EMS accident records are unacceptable.

More specifically, there’s a big difference in how safe one air ambulance is to another. The NTSB pointed out that no matter the cost and makeup of the air ambulance – a $800,000 single engine model versus a $12 million twin-engine autopilot helicopter – Medicare reimbursement is the same.

It’s likely the Mayo Clinic helicopter was on the elite end of medical transport. But key questions to be answered about any medical helicopter accident will involve:

It’s unclear what’s happened at the FAA in the past year. The Popular Mechanics article and intensified scrutiny around air ambulances triggered both voluntary safety measures and federal rule proposals. More helicopters came with helmets equipped with night vision goggles, for example. A rule proposed by the FAA in 2010 received final comments in January of this year. It included requirements around pre-flight checks, minimum weather requirements and training – some of which trade association had already required or implemented.

But the FAA regulation bogged down – due in part to partisan issues around the FAA – and it’s unclear after reviewing the federal register whether the rule was ever finalized.

Get the latest news alerts: Follow WRAL Tech Wire at Twitter.