SEATTLE — Richard Bach, the author of the 1970s best-selling novella “Jonathan Livingston Seagull” among other spiritually oriented writings often rooted in themes of flight, was in serious condition Saturday after his small plane crashed in Washington state.

His son, James Bach, told The Associated Press that his father was on his way to visit a friend on San Juan Island on Friday when his amphibian plane clipped a power line during landing and crashed.

James Bach said his 76-year-old father, who was flying alone, suffered a head injury and broken shoulder. He was listed in serious condition at Harborview Medical Center.

“Right now we’re waiting for the sedation to wear off, for him to fully wake up,” the son said Saturday morning.

In “Jonathan Livingston Seagull,” published in 1970, Bach writes of a philosophically minded seagull seeking to rise above the flock, which is focused on the dull regimen of finding food scraps. Jonathan is banished from the group only to come upon more enlightened gulls who guide him to spiritual lessons, which Jonathan then imparts to others.

The short, simply crafted book gained little to no critical attention upon publication, but rose to No. 1 for several weeks on the New York Times bestseller list, and Bach quickly drew a loyal following.

Besides “Seagull,” his other popular works include “Illusions: The Adventures of a Reluctant Messiah,” a story of a Midwestern barnstorming pilot’s quest for self-discovery.