Before you do this procedure, engage the ramp service door safety connector pin. 在执行此步骤之前，请连接斜坡服务门安全连接器插销。
A.Insert the pin of the apron service door security connector, then you can perform this procedure. B.The ramp service door safety pin should be engaged until you start this procedure. C.Firstly you should perform this procedure then you can engage the ramp service door safety connector pin.正确答案A
