From the QRH 80.01:
STRAIGHT-IN-APPROACH WITH ONE ENGINE INOPERATIVE
For performance reasons, do not extend flaps full until established on a final descent to landing. If a level off is expected during the final approach, perform the approach and landing in CONF 3.
If over-weight (immediate return):
if the aircraft weight is above the maximum weight for circling in CONF 3 (given in the table below): The aircraft cannot maintain flight level with CONF 3 and the landing gear down.