"descend onto" is correct and usable in written English.
You can use it to describe the action of someone or something arriving at a lower level, such as a hill. For example, "The helicopter descended onto the rooftop."
Early in the morning, an army of older workers descend onto Beijing's streets, rummaging through bins for recyclable materials.
Today, anyone who wants to descend onto the glacier has to use either a telepherique or a system of extremely steep iron ladders and hand rails.
What quarterback is going to descend onto a Browns team with no defense or skill position players – same as it has been since 1999 – and save the day?
He pointed out that the two streets were stops on the elevated No.7 train, which runs down the center of the boulevard, and commuters using those stops must descend onto busy streets with dangerously little curb.
5 p.m. 1) BEACH FLAVORS When migrants from Mumbai's outlying areas arrive, they descend onto Chowpatty Beach, a surprisingly pristine beach in the middle of this throbbing city of 17 million or so.
About 2,500 skiers descend onto the Rendezvous Trails outside Yellowstone National Park for one of the season's first races and festivals, which includes all-level clinics taught by Olympic athletes, yoga, beer tasting, a film festival and a chance to try the ski-shoot sport of biathlon.
From there, I watch planes descending onto the runway.
About a dozen commandos descended onto the ship on Sept. 19.
"I felt like an alien descending onto Earth for the first time," Ms. Redmond said.
Here goes 8.00pm: Lily Allen descends onto stage on the back of a black fish - and we're off!
The prehistoric shriek of hadeda ibises announces the dusk, and a flock of white egrets descends onto the lawn.
