A preliminary report released Friday by the National Transportation Safety Board (NTSB) indicates that no ice was found on the Pilatus PC-12 airplane that crashed near Bellefonte March 26.

While initial speculation focused on whether icing on the plane caused the crash, according to the NTSB report, none of the emergency first responders reported ice on the plane when they first arrived on the scene.

University Park Airport Director Bryan Rodgers said there were three reported icing emergencies in the Centre County area between 1 and 7 p.m. that day. He added that he had not seen that many emergencies in such a time period during his 15 months as airport director. "The number of icing emergencies was uncommon," Rodgers said.

The report states that the aircraft's icing controls were switched on, but were on a low setting, which Cox said is typical.

According to the report, the plane's de-icing panel indicated that the plane's de-icing boots were on a normal three-minute cycle, Cox said.

Rodgers said the de-icing boots are located on plane's wings and can be activated by the pilot. The boots are located on the leading edges of the wings and horizontal tail surfaces to keep ice from interfering with regular air flow over the wings.

"The devices pop loose and are meant to break the ice formed on the wing," Rodgers said.

The Pennsylvania State Police interviewed several witnesses, who described the plane as making a slow spin toward the ground with its right wing pointed up and its left wing pointing downward, according to the preliminary report.

The preliminary report also indicated that two weather advisories were issued at 12:15 and 2:05 p.m., which called for occasional moderate ice and rime, or water droplets freezing on a cold surface.

Rodgers said weather advisories, issued by the Federal Aviation Administration in New York, are common.

NTSB Senior Air Safety Investigator Paul Cox said a factual report would be released within four to six months after further investigation of the accident.

"You're not going to know everything in five days," he said. "We'll take this information and try to expand it."

The crash occurred shortly before 2 p.m. March 26 along Route 150 near the construction site of the new Centre County Correctional Facility.

Killed in the crash were Jeffrey Jacober, 51; Karen Jacober, 49; Eric Jacober, 15; Gregg Weingeroff, 49; Dawn Weingeroff, 42; and Leland Weingeroff, 10; all from Providence, R.I.

Jeffrey Jacober, Karen Jacober and Eric Jacober are the parents and brother of Penn State men's lacrosse captain Michael Jacober.