Rules of the Air Article 46
When it becomes evident that flight in VMC in accordance with its current flight plan will not be practicable, a VFR flight operated as a controlled flight shall:1. request an amended clearance enabling the aircraft to continue in VMC to destination or to an alternate aerodrome, or to leave the controlled airspace concerned; or2. if no clearance in accordance with (1) can be obtained, continue to operate in VMC and notify the appropriate ATC unit of the action being taken either to leave the controlled airspace or to land at the nearest suitable aerodrome; or3. if operated within a control zone, request authorization to operate as a special VFR flight; or4. request clearance to operate in accordance with the instrument flight rules.
中文原文 飛航規則第46條
接受管制之目視飛航航空器顯然不能依照現行飛航計畫於目視天氣情況下飛航時，應按下列規定辦理：
一、請求修改許可，俾航空器能繼續以目視天氣情況飛往目的地或備用機場，或飛離有關之管制空域。
二、不能依前款獲得許可時，應繼續作目視天氣情況之飛航，並將採取之行動，如飛離管制空域或降落最近之適當機場等，告知適當之航管單位。
三、在特定管制空域內飛航，應請求特種目視飛航許可。
四、請求許可作儀器飛航。
一、請求修改許可，俾航空器能繼續以目視天氣情況飛往目的地或備用機場，或飛離有關之管制空域。
二、不能依前款獲得許可時，應繼續作目視天氣情況之飛航，並將採取之行動，如飛離管制空域或降落最近之適當機場等，告知適當之航管單位。
三、在特定管制空域內飛航，應請求特種目視飛航許可。
四、請求許可作儀器飛航。