AKRON, Ohio — With no survivors and no sign of a distress call from the plane that slammed into an Ohio apartment house, investigators will comb charred wreckage, aircraft records, weather information and video for clues about what caused the crash that killed nine people onboard.

The cockpit voice recorder from the aircraft was sent Wednesday to a lab for analysis, and investigators expected to begin recovering parts of the plane on Thursday, said Bella Dinh-Zarr, vice chairman of the National Transportation Safety Board.

It crashed Tuesday afternoon in Akron as it approached the small airport where it was to land.

Another pilot who had just landed at the airport reported hearing no distress calls despite being on the same communications frequency as the aircraft that went down, the NTSB said. It said the small airport doesn’t have a control tower with which the plane might have communicated.

Investigators have surveillance video from a nearby construction company that shows the plane coming in along treetops, banking to the left, crashing and exploding into flames and a cloud of black smoke. The left wing hit the ground first before the plane crashed into the apartment house, Dinh-Zarr said.

“There are many things that could have resulted in this,” she said. “We are not speculating.”

The two pilots were killed, along with seven associates from Pebb Enterprises, a Boca Raton, Florida, real estate investment company. No one was home at the apartments, and there were no other injuries.

A statement posted on Pebb’s website said its staff was heartbroken to learn two principals and five employees had died in the crash. They were on the second day of a multicity Midwestern trip to look at property for potential shopping centers.