The lighthouse flashes signals twice a minute 灯塔每一分钟发出两次信号。
2.
Busy - flash signal 话中点灭信号
3.
A civil aircraft in emergency on the sea shall also flash signals to vessels and national maritime search and rescue service 民用航空器在海上遇到紧急情况时，还应当向船舶和国家海上搜寻援救组织发送信号。
4.
Article 151 a civil aircraft in emergency shall flash signals and report to air traffic control unit to request rescue ; the air traffic control unit shall notify immediately the search and rescue coordination centre 民用航空器在海上遇到紧急情况时，还应当向船舶和国家海上搜寻援救组织发送信号。
