The phrase "as a supernumerary" is correct and usable in written English.
It can be used in contexts where someone is serving in a supplementary or additional role, often in a theatrical or organizational setting.
Example: "She joined the production as a supernumerary, assisting with various tasks behind the scenes."
Alternatives: "in a supplementary role" or "as an extra."
Mr. Taplin enjoyed appearing on the Met stage as a supernumerary.
James O'Neill made his stage debut as a supernumerary in a Cincinnati, Ohio, production of The Colleen Bawn (1867).
He made his first known public appearance playing alongside his father in the basilica as a "supernumerary" violinist in 1696.
In the mid-1940's, when I was a student at City College, I supplemented my income by working as a supernumerary at the Metropolitan Opera House, then at 39th Street and Broadway.
For the last 30 years, during his career as a supernumerary, or extra, for operas and ballets at the Met, he has marched as a soldier in "War and Peace" and transformed himself into a witch in "Hansel and Gretel".
These days with his short, neatly trimmed gray beard, he could easily be cast as a supernumerary in a Wagner production.
It may result from the operation of pneumatic hammers or may occur in individuals with various disorders, such as a cervical rib, a supernumerary (extra) rib arising from a neck vertebra.
The year he graduated, Darwin was given a supernumerary position as a gentleman naturalist and geologist on the second voyage of HMS Beagle, a trip that lasted five years.
Thus, paralysed patients could experience a supernumerary prosthesis as part of their own bodies while maintaining ownership of their real limbs.
These results are important because they demonstrate that the central nervous system, under certain conditions, when faced with two equally probable locations of a seen limb, can "split" the limb representation in two, making people experience a supernumerary limb as being part of their own body.
The author of 30 books, he is a professor of philosophy at Birkbeck College in London, and a supernumerary of St Anne's College, Oxford, as well as a UN human rights activist.
