Middle seat deadhead pay for United pilots
Short answer
Yes. A required Economy middle seat, including Economy Plus and Premium Economy, pays Add Pay of 50% of the deadhead leg's scheduled flight time.
What the contract says
“If a Pilot is required to deadhead in a middle seat in Economy Class (including Economy Plus and Premium Economy), he shall receive Add Pay equal to fifty percent (50%) of the scheduled Flight Time of the deadhead leg. A Pilot may not reseat himself to obtain such Add Pay.”
How do I claim it?
Submit a pay claim with supporting documentation, including the reservation number, the seat you actually sat in and a description of what happened. § 5-C-1-g
Can they move me to a better seat instead?
Yes. If an Economy Plus or Premium Economy aisle or window seat becomes available before departure, you may be moved there from an Economy Plus or Premium Economy middle seat. § 5-C-1-g-(1)
This page explains contract language; it is not legal advice. If your situation is not covered, ask your union representative.