Date:	Thursday 8 December 2005
Time:	19:14
Type:	Boeing 737-7H4 (WL)
Owner/operator:	Southwest Airlines
Registration:	N471WN
MSN:	32471/1535
Year of manufacture:	2004
Engine model:	CFMI CFM56-7B22
Fatalities:	Fatalities: 0 / Occupants: 103
Other fatalities:	1
Aircraft damage:	Substantial, repaired
Category:	Accident
Location:	Chicago-Midway Airport, IL (MDW) -   United States of America
Phase:	Landing
Nature:	Passenger - Scheduled
Departure airport:	Baltimore/Washington International Airport, MD (BWI/KBWI)
Destination airport:	Chicago-Midway Airport, IL (MDW/KMDW)
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
Southwest Flight 1248 was scheduled for a 14:55 departure out of Baltimore/Washington International Airport, but the aircraft's departure was delayed until 16:50 because of weather. After circling for over 30 minutes the crew were cleared for landing at Midway's runway 31C (6522 feet long). The crew choose to use the auto-braking system at "max". The approach speed was 120 kts and 132 kts by the time it landed. The aircraft touched down with about 4,500 feet of remaining runway. The flying pilot (captain) stated that he could not get the reverse thrust levers out of the stowed position. The first officer, after several seconds, noticed that the thrust reversers were not deployed and activated the reversers without a problem. The reversers were activated 18 seconds after touchdown. Noticed that the airplane was not decelerating normally, both crew members applied maximum braking manually. The airplane departed the end of the runway, rolled through a blast fence, a perimeter fence, and onto a roadway. The 737 collided with some vehicles and came to rest on the corner of S Central Avenue and W 55th Street. A six-year-old boy in one of the vehicles has died as a result of injuries sustained in the accident.

PROBABLE CAUSE: "The National Transportation Safety Board determined that the probable cause of this accident was the pilots’ failure to use available reverse thrust in a timely manner to safely slow or stop the airplane after landing, which resulted in a runway overrun. This failure occurred because the pilots’ first experience and lack of familiarity with the airplane’s autobrake system distracted them from thrust reverser usage during the challenging landing.

Contributing to the accident were Southwest Airlines’ 1) failure to provide its pilots with clear and consistent guidance and training regarding company policies and procedures related to arrival landing distance calculations; 2) programming and design of its on board performance computer, which did not present critical assumption information despite inconsistent tailwind and reverse thrust assessment methods; 3) plan to implement new autobrake procedures without a familiarization period; and 4) failure to include a margin of safety in the arrival assessment to account for operational uncertainties. Contributing to the severity of the accident was the absence of an engineering materials arresting system, which was needed because of the limited runway safety area beyond the departure end of runway 31C."

00:53 UTC / 18:53 local time:
KMDW 090053Z 10011KT 1/2SM SN FZFG BKN004 OVC014 M03/M05 A3006 RMK AO2 SLP196 R31C/4500FT SNINCR 1/10 P0000 T10331050

01:53 UTC / 19:53 local time:
KMDW 090153Z 23003KT 1/2SM SN FZFG VV002 M04/M05 A3004 RMK AO2 SLP191 R31C/4000V4500FT SNINCR 1/10 P0000 T10391050

SKYbrary 
NTSB

photo (c) NTSB; Chicago-Midway Airport, IL (MDW); 08 December 2005; (publicdomain)

photo (c) NTSB; Chicago-Midway Airport, IL (MDW); 08 December 2005; (publicdomain)

photo (c) NTSB; Chicago-Midway Airport, IL (MDW); 08 December 2005; (publicdomain)

photo (c) NTSB; Chicago-Midway Airport, IL (MDW); 09 December 2005; (publicdomain)

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