Engine failure, emergency descent, heading 120.

发动机失效，航向120紧急下降。

youdao

All stations, emergency descent between WF and VM, all aircraft below 3900m between WF and VM leave corridor to the east immediately.

各台注意，WF和VM之间油紧急下降的航空器。WF和VM之间所有低于3900米的航空器立即向东离开走廊。

youdao

This is hardly surprising, given that an emergency descent can be terrifying if you do not why it is happening or how it is going to end.

BBC: What to do when planes lose pressure