Class G Airspace in the North Cascades

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For most glider pilots in the USA Class G air space (uncontrolled air space) is something that is of no practical importance, except possibly for takeoff and landing.  Class G allows operations “clear of clouds” and with a minimum of 1 mile visibility”.  Over Arlington Class G extends to 700 ft above ground (AGL) and gliders don’t lend themselves to scud running.  We don’t operate unless the cloud base around Arlington is at least 2000 ft AGL for pattern flying and at least 3000 ft for extended local flying and then fly basically in Class E (500 ft below clouds, 1000 ft above, 2000 ft away, 3 mile visibility or – above 10,000 ft – 1000 ft above and below, 1mile laterally and 5 miles visibility).    However, this changes when flying further east, i. e. flying in the mountains.  First, the upper limit of Class G increases to 1200 ft AGL somewhere on the back side of Jordan ridge and then it is just a matter of cloud base and terrain how often sailplanes will be in class G.  Actually the upper limits of class G will jump significantly higher further east (up to 12,000 ft ASL) but the “clear of clouds, 1 mile visibility’ rule applies only up to 1200 ft AGL (check your charts).  This somewhat complicated airspace setup is based  on limited radar coverage in the mountains.

Provided that one stays within 1200 AGL of the terrain one can take advantage of the “clear of clouds, 1 mile visibility” rule throughout the North Cascades.  This rule is very  helpful for soaring pilots, who are always trying to get as high as possible in the mountains to stay in safe gliding range of a suitable landing field and the cloud base is quite often below the mountain tops.  One can assume that very few other aircraft are interested in flying close to the rocks and close to the clouds so that there is only a minor collision danger – except with other sailplanes (and for Whidbey Island F-18s that fly on designated low level routes).  Good situational awareness (by eyeball, radio and FLARM) is required when operating in such conditions.  As always, check your charts, know where you are and be aware of any applicable rules and limitations.