B757 Undifferentiated or Other Model
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Last 90 Days 195; Flight Crew Total 12952; Flight Crew Type 1639
Distraction; Situational Awareness
Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Unstabilized Approach
Air Traffic Control Issued Advisory / Alert; Flight Crew Regained Aircraft Control; Flight Crew Became Reoriented
Human Factors
Set up for ILS XL after all-nighter to ZZZ. Conditions at ZZZ : rain; 1300 ft ceiling; visibility about 5 miles; dark; 15 knots of wind from NE. Assigned 170 knots to marker. Reached marker at flaps 20; 170 knots. Called for gear down at marker then flaps 25. I didn't wait long enough between gear and flaps 25; so configuration warning horn sounded. At first I didn't recognize what the horn was for so I grabbed the yoke thinking it might be the autopilot disengaging. I then realized it was just the configuration warning. I leaning to right to look for the flaps 30 speed limit (I normally turn up the panel lights on approach; but I forgot this time). After reading the flap limit speed I looked back at ADI and saw we were in a nose low and left bank attitude. It was then I realized the autopilot was off. I must have hit the autopilot disconnect switch when I grabbed the yoke. I pulled back up to flight director and got back on correct LOC/GS path. At this time ATC issued a low altitude alert. Rest of approach and landing uneventful.
B757 Captain report accidentally disconnecting the autopilot; becoming distracted and receiving a low altitude alert from ATC while on final approach.