NORTH COLLINS, N.Y. -- The NTSB has released additional details about the agency's preliminary report on the factors surrounding the plane crash in North Collins that killed three people a little more than a week ago.

It was supposed to be a fun Sunday in the sky - a group of six private planes flying to Pennsylvania. A Cessna and Piper were the first to take off and dropped off radar just before 9:30 a.m. on Sept. 25.

"Preliminary talk is that is was truly an accident, and those are the saddest ones because everyone always feels that accidents are avoidable, but I guess that's why we use the term accident," said Dave Mittlefehldt, the president and CEO of Prior Aviation Service Inc.

The NTSB's preliminary report says witnesses saw the Piper climb and crash into the Cessna. The wreckage shows the Cessna's tail was sheared off by the Piper's propeller.

"It looks like he was level at 3,500 feet for about 50 seconds before the impact. When I say level though, it's difficult for a pilot to hold their altitude within one foot. So sometimes plus or minus 100 feet in terms of aviation at 3,500 feet would be pretty standard. It would be like trying to drive your car within an inch, perfectly centered in the lane," said Robert Gretz, an NTSB senior air safety investigator.

There were no distress calls or reports of turbulence. NTSB officials say blind spots do not appear to have been a factor.

Despite the FAA's required annual inspection, the NTSB has not ruled out a maintenance issue or malfunction. The Cessna was made in 1948, the Piper in 1971. 

"There's a lot of airplanes that are still flying from World War II. They're in top shape. As long as you follow all the air worthiness directives and the service bulletins for the make and model of that airplane, the age of the airframe is pretty much irrelevant," said Mittlefehldt.

The Cessna piloted by Paul Rosiek, 60, of Hamburg, took off first. The Piper, flown by Richard Walker, 69, of Eden, followed with wife Kathleen inside. Each pilot had nearly 800 hours of flight time.

"To get a private pilot license, the FAA requires 40 hours, so they were well above," said Gretz.

Both pilots were following federal safety rules.

The NTSB stresses that the preliminary report is subject to change. Its full report will take six to 12 months when a five-member presidential appointed panel will determine the like cause of the crash.