S. 254(1) : Appellate Tribunal-Powers-De novo enquiry-Bad debt-Where Appellate Authority remands case for a determination on a selected issue or aspect of assessment, parties are fully aware of parameters within which fresh enquiry is circumscribed and limited-Rigours of limitation are totally removed-Tribunal had directed Assessing Officer to consider question of disallowance for bad debts/advances being written off-Tribunal’s order did not set aside or cancel subject assessment orders requiring a fresh assessment. [S. S. 36(1)(vii), 153(5), 153(6), Art. 226]