Shortly after an airliner made an aggressive maneuver to avoid colliding with a B-52 last month over North Dakota, the bomber nearly collided with a small private plane as it flew past the Minot airport, according to the National Transportation Safety Board.

Investigators released their preliminary report Wednesday on the July 19 incident that happened after the bomber completed a flyover at the North Dakota State Fair in Minot. The close call with Delta Flight 3788 is well known because of a video a passenger shot of the pilot's announcement after making an abrupt turn to avoid the bomber. But the fact that the B-52 subsequently came within one-third of a mile of a small Piper airplane hadn't been previously reported.

The SkyWest pilot told his passengers that day that he was surprised to see the bomber looming to the right, and the U.S. Air Force also said that air traffic controllers never warned the B-52 crew about the nearby airliner. Officials said at the time that the flyover had been cleared with the FAA and the private controllers who oversee the Minot airport ahead of time.

These close calls were just the latest incidents to raise questions about aviation safety in the wake of January's midair collision over Washington, D.C., that killed 67 people.

The NTSB report doesn't identify the cause of the incidents, but the transcript of the conversation between the three planes, the air traffic controller on duty in Minot and a regional FAA controller at a radar center in Rapid City, South Dakota, show several confusing commands were issued by the tower that day. Investigators won't release their final report on the cause until sometime next year.

With the B-52 and Delta planes converging on the airport from different directions, the controller told the Delta plane that was carrying 80 people to fly in a circle to the right until the pilot told the controller he didn't want to do that because the bomber was off to his right, so he broke off his approach.

"Sorry about the aggressive maneuver. It caught me by surprise," the pilot can be heard saying on the video a passenger posted on social media. "This is not normal at all. I don't know why they didn't give us a heads up."

At one point, the controller intended to give the Delta plane directions but mistakenly called out the bomber's call sign and had to cancel that order.

Less than a minute after the B-52 crossed the path of the airliner, it nearly struck the small plane that was also circling while the bomber flew past the airport on its way back to Minot Air Force Base where 26 of the bombers are based.

Aviation safety consultant Jeff Guzzetti, who used to investigate plane crashes for both the NTSB and FAA, said the controller didn't give the commands for the Delta and Piper planes to circle soon enough for them to stay a safe distance away from the bomber.

The transcript shows the local controller calling the regional FAA controller to get permission every time before he issued a command to the planes. Guzzetti said it is not clear whether taking that extra step to consult with the other controller delayed the commands or whether the Minot controller simply didn't anticipate how close the planes would come.

"It all just kind of came together at the same time very quickly, and this controller was not on top of it," Guzzetti said.

The Minot airport typically handles between 18 and 24 flights a day. But at this moment, three planes were all arriving at the same time.

After the close calls, all the planes landed safely.

These North Dakota close calls put the spotlight on small airports like Minot that are run without their own radar systems, but it is not clear whether that contract tower program that includes 265 airport towers nationwide had anything to do with the incident. There was one controller staffing the tower in Minot at the time of incident, and a controller at a regional radar center in Rapid City was helping direct planes in the area.