The American Airlines flight that caught fire soon after taking off from Denver International Airport in March had several parts installed incorrectly and fuel leaks, according to a preliminary report released Thursday. 

The Dallas-bound aircraft had one loose part inside the right engine installed in the wrong direction and fuel leaking from the fitting of another part that was also fastened incorrectly, according to the National Transportation Safety Board (NTSB) report.

Soon after the plane took off, the crew noticed issues with the right engine, the report said. 

An American Airlines plane that caught fire in Denver had dark streaking which was consistent with in-flight streamlines, according to a National Transportation Safety Board (NTSB) report. (NTSB)

During an inspection of the damage, investigators saw that the plane “exhibited heat/smoke/burn indications near the right engine nacelle, right wing, right side of the fuselage aft of the wing, the right main landing gear, and the right main landing gear wheel well,” the report said. 

In addition, “the lockwire of a fuel fitting on the variable stator vane (VSV)” was loose and installed in the incorrect direction, in addition to other issues. 

Further examination of the engines found that one fan blade platform was fractured, according to the report.

Another part of the plane that controls airflow through the turbine’s compressor was found to be “incorrectly fastened and secured … allowing fuel to leak from the fitting.”

American Airlines plane catches fire at Denver International Airport. (X / @flynnstone)

American Airlines said 172 passengers and six crew members were on board at the time of the incident. 

The airplane had “substantial damage” while 12 passengers and the six crew members sustained minor injuries, according to the report.

Fox News Digital has reached out to American Airlines.