After a Delta flight made an emergency landing in Atlanta​ in February, a maintenance crew found there was barely any or possibly no oil in the aircraft's right engine, an NTSB report said.

The National Transport Safety Board found indications that the aircraft suffered an oil system failure in a preliminary report

Smoke in the cabin led to an emergency landing of a Delta flight in February. Only later did officials realize there was little to no oil in the aircraft's right engine. That reveal, coming in a National Transportation Safety Board preliminary report released Wednesday,