devil's advocate: Which did it say?
OUTR TK UNUSABLE
CTR TK UNUSABLE
Indeed, no way of remembering after all this time, but just imagine for a second the twilight inside SIM, the green font on a black background with reading glasses on .. OTR TK or CTR TK? Fuel page not in sight due to STS overlay on the SD.
The type of perception error I am perfectly capable of. Could have been wrong programming and OUTR shown instead of CTR as well. Same issue except on the side of the SW engineer.