The pilots of a business jet that crashed into an Akron apartment building last week, killing all nine people on board, were warned that the weather had made landing conditions barely suitable, federal investigators said Wednesday.

The jet crashed and exploded Nov. 10 less than 2 miles from Akron Fulton International Airport. No one on the ground was injured. The plane, flying from Dayton, was carrying two pilots plus seven people from a Boca Raton, Florida, real estate development company.

A preliminary report released Wednesday by the National Transportation Safety Board said a flight instructor on another plane radioed the pilots after landing that his plane had broken out of the cloud deck at the minimum altitude allowed for landing at the airport.

One of the pilots thanked the flight instructor for the update, the report said.

Officials said last week that weather would be one of the key areas examined in determining what caused the crash.

Anthony Brickhouse, a professor and expert on plane crash investigations at Embry-Riddle Aeronautical University in Daytona Beach, Florida, said weather was "the first thing" that caught his attention when he learned about the crash.

The minimum altitude is the lowest point where a pilot can see the runway and is allowed to land, Brickhouse said. The pilots were using flight instruments to land the 10-passenger, twin-engine jet because clouds were hovering just 600 feet above the runway, according to the report.

"Instrument flying is even more precise than visual flying because you have so many parameters you have to account for," Brickhouse said.

NTSB investigators said last week that they had reviewed 30 minutes of conversations between the pilots from the cockpit voice recorder. The pilots discussed weather and the landing but made no distress calls before the crash, investigators said.

The report said the pilots were in contact with air traffic controllers from a larger, nearby airport about their instrument approach at 10 miles out from Akron Fulton, which doesn't have a control tower. The jet crashed moments later. A chilling video recorded by a surveillance camera from a business near the crash site shows the jet flying at high speed over trees before hitting the apartment building and exploding.

NTSB officials said the plane was intact before it crashed and was equipped with a ground proximity system, which is supposed to alert pilots when they're flying too low. The investigation into the cause of the crash will take months to complete, NTSB officials said.