Air India officials and scores of Indian government investigators have been at the crash site since Thursday. No initial findings have been disclosed so far, but investigators are considering at least three key possible issues, according to a source with direct knowledge.

Investigators are assessing if there are any issues related to engine thrust, which is the force produced by the engine to push it forward through the air. Investigators are also looking at any possible operational issues with flaps. Officials are also assessing why the landing gear was open for so long after take-off. A possible bird strike is not a focus of the probe. The source added that officials are also looking at any possible fault of Air India, including any possible maintenance issues.