This often occurs when upper air is subsiding, such as under anticyclonic conditions, and is also frequently found when radiation fog has formed overnight.
12.
Subsequently autoland systems became available on a number of aircraft types but the primary customers were those mainly European airlines whose networks were severely affected by radiation fog.
13.
Radiation fogs occur at night, and usually do not last long after sunrise, but they can persist all day in the winter months especially in areas bounded by high ground.
14.
However, the term is usually a synonym for radiation fog which is very shallow; in some cases the depth of the fog is on the order of tens of centimeters over certain kinds of terrain with the absence of wind.
15.
Investigators from the State Administration of Work Safety concluded that the captain, on his first flight into Yichun, switched off the autopilot and approached the runway covered by radiation fog despite the fact that visibility of was below the minimum of.
16.
As the temperature drops rapidly in this period with little wind it is common for a rapid condensation of water vapor, the basic condition for a fog formation known as radiation fog, which characteristic is a thick and low fog, significantly impacting operations.
17.
At the same time it became evident that the requirement for a true " zero visibility " operation ( as originally envisaged in the ICAO Category definitions ) had diminished, as " clean air " laws had reduced the adverse effect of smoke adding to radiation fog in the worst affected areas.
18.
Radiation fog may develop over inland areas of Great Britain and can persist for hours or even days in the winter and can pose a major hazard for drivers and aircraft . Fog is more common inland and on higher altitudes; mainly during winter and during the morning at times of high pressure.
