Air ambulance companies that want to use the devices must first receive approval from the Federal Aviation Administration; however the FAA has a shortage of inspectors that can drag out the approval process by months, USA Today said.

"The guys that are flying are pretty frustrated that they can't get these," Gary Sizemore, president of the National EMS Pilots Association, told USA Today.

The renewed call to equip more medical helicopter with night-vision gear came after a series of five crashes this year, four of which occurred at night.

An FAA spokeswoman told USA Today it was working to streamline the inspection and approval process.