Could you tell me when does the plane leave?(改错）

Could you tell me when the plane leaves ?

Could you tell me when the plane leaves ? 这是宾语从句,所以后面的句子要用陈述句的形式,不能用问句

没有错误....

Could you tell me whe the plane leave?
你的原句中是疑问句语序，
宾语从句中应用陈述句语序

去掉does
从句直接用陈述语气

宾语从句,去does