18_1B SF-SL Acalanes Ridge

Location / Airway

Location / Name

CALIFORNIA: Contra Costa County

Commonly called Walnut Creek Arrow
AKA; Department of Commerce site No.1B, San Francisco-Seattle Airway;
1B SF-SL Acalanes Ridge

GPS: 37.902652, -122.078105

Contract Air Mail

CAM #8 Seattle WA - Los Angeles CA
San Francisco-Seattle Airway
San Francisco-Redding Section

CAM #18 San Francisco CA-Chicago IL
San Francisco-Salt Lake Airway
San Francisco-Reno Section

Operator

Vern C. Gorst awarded CAM #8 on December 31, 1925
Pacific Air Transport subcontraced CAM #8 on March 6, 1926

Boeing Air Transport, awarded CAM #18 on January 29, 1927 (western portion of the Transcontinental Airway)

 

Observations and Notes

This is a rare double shafted, double pointed arrow. Two airmail routes passed over this arrow. Contract Air Mail (CAM) route #8, Seattle WA - Los Angeles CA flown by Pacific Air Transport began it's flights on September 15, 1926 and Contract Air Mail #18, Chicago IL - San Francisco CA, flown by Boeing Air Transport began it's flights on July 1, 1927.

The Acalanes Ridge Arrow is located in a county park on a ridge overlooking the city of Walnut Creek, Ca.  The park is mainly used for hiking.  The trail up to the arrow is well maintained, and took us about 20 minutes to get there from where we parked the car.

This arrow is unique out of all the arrows we have been too, due to it having ‘two tails’ and ‘two arrow points.  Both tails are on an uphill slant, while the arrow points are on a downhill slant.  Only the center portion of the arrow where the beacon once stood is on level ground.  The arrow is complete and in basically good condition.  However, people have come up here and painted graffiti over the entire arrow.

Measurements:
The left tail to both the left arrow point & right arrow point are 57 feet in length.
The right tail alone is 24 feet in length.
The pilot would approach the right tail of the arrow on a compass heading of 329° (N-NW).
The pilot would approach the left tail of the arrow on a compass heading of 25° (N-NE).
The pilot would exit the right arrow point on a compass heading of 48° (NE).
The pilot would exit the left arrow point on a compass heading of 25° (N-NE).
(All measurements and compass headings are approximate).

It is known as "1B SF-SL", which would have been painted on the generator shack, to let the pilots know their location.

Drone Photos

Links

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