Two Icelandic skydivers who died during weekend jumps at a popular southwest Florida camp did not deploy their main parachutes, the co-owner of the facility said Sunday.

Deputies found the bodies of the skydiving instructor and a student Saturday after the two didn’t return from a jump with a group, setting off an hours-long air and ground search around the Zephyrhills facility, about 30 miles northeast of Tampa. Pasco County sheriff’s authorities identified the victims as 41-year-old instructor Orvar Arnarson and 25-year-old student Andrimar Pordarson of Iceland. The men jumped separately, not in tandem.

The fact that the men didn’t deploy their main parachutes could mean that they lost altitude awareness and didn’t know where they were during the dive, which is unusual, said T.K. Hayes, co-owner of Skydive City.

Both men had backup automatic activation devices, which deploy if the main parachutes are not deployed in time.

“Those devices activated on both of them … but the reserves did not have time to deploy fully,” Hayes said. “They were out of the containers but not inflated in time before they impacted.”

Hayes was at the scene with officials Saturday, sorting through the men’s gear to determine whether all parts had been functioning properly.

“Like most accidents, most of the time it’s human error,” he said. “I doubt there’s an equipment problem here, to be honest.” But he stressed that authorities are still investigating.

The two men had successfully completed two other jumps Saturday morning with 20 other people. But when they didn’t return from their third jump, their disappearance tipped off a search, Pasco County sheriff’s spokeswoman Melanie Snow said.

The bodies were discovered by spotters from the air early Saturday evening in woods south of the Zephyrhills Municipal Airport, Snow said.

The victims were part of a group of about 12 who travel from Iceland to Florida every year to jump, Hayes said.

Arnarson, the instructor, had been to the facility before, but Pordarson had not, Hayes said.

The area is a popular destination for skydivers. Skydive City is a 14-acre property that includes RV campgrounds, a tiki bar, cafe and regular shows by a reggae band, according to its website.

Hundreds of skydivers jump each day at the site this time of year. Hayes estimates that overall, the facility assists about 75,000 jumps a year. Accidents are rare, but they happen, he said.

Last year across the U.S., 19 skydivers died out of 3.1 million jumps, according to the United States Parachute Association.

“As an industry, the safety record continues to improve as the decades go on as we improve training and equipment … but it’s not a fail-safe sport,” Hayes said.

Last month, near Seattle, dozens of volunteers spent four days searching through snowy weather and fog after a 29-year-old Florida man didn’t return from a skydiving jump above Washington’s Cascade foothills. Kurt Ruppert, of Lake City, was wearing a special wing suit with fabric under the arms to allow him to glide like a flying squirrel.

“With skydiving, of course, the consequences of small mistakes are going to be pretty grave,” Hayes said.

The Federal Aviation Administration does not regulate the United States Parachute Association. The group is a self-regulated, but the FAA may get involved in accident investigations to determine whether the pilot or the plane were to blame. Hayes said that was not the case in Saturday’s incident.