"Sometimes when we bring the helicopter up from the ground, [the basket] will start to spin," Apolinar said. "We have a line attached to the basket that's supposed to prevent that. Today, it didn't."
While Apolinar described the issue of spinning as "very rare," with the last case three or four years ago, he said the potential for the basket to rotate in such a wild manner is "a known phenomenon in the hoist rescue industry."
The woman's rescue started when authorities received a call that she'd been injured on the summit trail of Piestewa Peak, the second-highest point in the Phoenix area.
The woman, who has not been named, suffered facial and head injuries from a ground-level fall, authorities said. Given the woman's location, authorities opted for a long-line rescue, in which a rescuer would rappel down from a helicopter to secure the woman in a stretcher at the end of a long line before flying her to the hospital.
But in this case, the operation quickly went awry when a line broke that is intended to prevent the basket from spinning as it interacts with the helicopter's rotor wash, said Derek Geisel, the rescue pilot. The basket spun wildly for about 40 seconds, with the crew raising and lowering the 74-year-old several times while trying to slow the spinning.
"When they start to lower the load, [the basket] does actually start to stop," Geisel said. "And then we slowly brought it back up, it gets into the same downwash from the aircraft and it started to spin again."
It wasn't until the helicopter began to fly away from its stationary position that the harsh motions started to subside.
"Once we got the forward flight, the spin got to the point where they were safely able to bring the patient up to the aircraft," Geisel said.
Phoenix Fire Captain Bobby Dubnow said he was the first to communicate with the woman after she was secured.
"I kind of was able to get in her face a little bit, make sure her eyes were open and told her everything was going to be okay," he said. "We were at least able to make some eye contact."
Dubnow said the injured hiker is in stable condition and "suffered no ill effect from that spin, other than being a little bit dizzy."
"We're not trying to minimise what happened up there," Dubnow said. He added: "It's something we don't expect, but we anticipate and we train for it. Nothing happened today that we weren't prepared to deal with."
On social media, people were shocked and left nauseated by the whirling footage. Some Twitter users responded by posting a memorable scene from an episode of "The Simpsons," in which Homer is repeatedly bumped in the head while being airlifted from Springfield Gorge.
