不正确.建议改为：
The jet of Malaysia airlines has disappeared for five days. After a long time of searching,it has not yet been found.
问题：
只有一架飞机,jet 用单数
航空公司 airlines 要用复数
had been disappeared 是被动形式,应改为主动,同时过去完成时在这里不能用,应改成现在完成时：has disappeared
five day 要加 s 成复数
a long times ——> a long time
the jets not yet be find ——> 语法错误.