forgetviviva

This question has several assumptions.

Logic structure: A does NOT lead to B, because C can lead to B.

Premise:  After crash in last August, new and more stringent rules was implented  => the increase of mechanical problems identified
Conclusion: human failure was not responsible for the fatal airplane crash last August
Assumption: There were at least as many mechanical problems as those before last August;
                     These (newly identified) mechanical problems are serious enough to cause crash by theirselves.

perhaps, even more assumptions can be listed.