DENVER (KDVR) — The National Transportation Safety Board (NTSB) released the initial investigation of the United Airlines flight 328 Boeing 777 engine failure.

The engine was made by Pratt & Whitney which is a subsidiary of Raytheon Technologies. Part of the statement said that the inlet and cowling separated from the engine and that two fan blades were fractured.

Read the full statement of what investigators determined and what departments were involved.

Aviation safety instructor Steve Cowell says the preliminary findings from the NTSB are only the beginning of what will likely be a months-long investigation.

“These are things that are general statements and that are generally known. It’s a statement to let the public know that the investigation is proceeding and this is what they found. They’ve found some cracks of significance in some of the fan blades. The question now is why did the cracks occur — that’s going to be the follow-up portion of the investigation,” Cowell said.

Pratt & Whitney has dispatched a team to work with investigators and says it is “actively coordinating with operators and regulators to support the revised inspection interval of the Pratt & Whitney PW4000 engines that power Boeing 777 aircraft.”