Before the Fall schedule changes took effect on September 5, UA 838 from SFO-IAD was operated by a 3-cabin 767 with the exception of Mondays, when it was operated by a 3-cabin 777 for KWI positioning.

With the September 5 schedule changes, UA 838 from SFO-IAD is now an A320 on weekdays with 752s on the weekend.

Nothing strange going on ...

Auguest 27: Monday
September 3: Monday
September 5: Fall schedule changes
September 8: Weekend