Date: | Tuesday 15 December 2015 |
Time: | 17:23 |
Type: | Boeing 737-3H4 (WL) |
Owner/operator: | Southwest Airlines |
Registration: | N649SW |
MSN: | 27719/2894 |
Year of manufacture: | 1997 |
Total airframe hrs: | 58630 hours |
Engine model: | CFMI CFM56-3B1 |
Fatalities: | Fatalities: 0 / Occupants: 138 |
Aircraft damage: | Substantial |
Category: | Accident |
Location: | Nashville International Airport, TN (BNA) -
United States of America
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Phase: | Taxi |
Nature: | Passenger - Scheduled |
Departure airport: | Houston-William P. Hobby Airport, TX (HOU/KHOU) |
Destination airport: | Nashville International Airport, TN (BNA/KBNA) |
Investigating agency: | NTSB |
Confidence Rating: | Accident investigation report completed and information captured |
Narrative:Southwest Airlines flight 31, a Boeing 737-300, N649SW, exited the taxiway while taxing to the gate and came to rest in a ditch at the Nashville International Airport, Tennessee, USA. Nine of the 138 passengers and crew onboard received minor injuries during the evacuation and the airplane was substantially damaged.
The airplane landed normally on runway 20R and exited at taxiway B2. ATC instructed the flight to taxi to the ramp (gate C20) via taxiway B, T3, and T4.
The captain reported he used landing lights to assist in the taxi along B and T3 and then extinguished the landing lights as the airplane crossed runway 13/31, but left the taxi lights on.
The flight crew reported that they had difficulty locating taxiway T4 as it appeared dark and there was glare from the terminal lights ahead. About 15 seconds prior to the excursion the airplane began a left turn briefly to a heading of about 065 degrees. Taxiway T4 was oriented about 045 degrees. The crew was searching for the turn to the ramp when the airplane then turned back to the right to a heading of 090 degrees, consistent with the heading toward gate C20. Three seconds later the airplane exited the taxiway into a grassy area with a large drainage ditch, east of the intersection of taxiways T4 and J. The nosegear collapsed, and the airplane came to rest angled to the right, on the left nacelle, right wing tip, and nose.
Shortly after the airplane came to rest an audible alarm began sounding in the cockpit which the flight crew indicated they could not silence. The pilot advised ATC that "we've cut the corner here and are off in the grass" and asked for ARFF equipment.
When the airplane stopped all the cabin lights went out for some time before the emergency lights came on. The flight attendants stated that they did not know what was going on so began yelling, "heads down, stay down" as they tried to call the pilots but there was no power on the interphones. The FAs initiated the evacuation a short time later. About one minute after the airplane came to rest, the pilots noticed that the slides were deploying and passengers were evacuating and the captain announced on the public address system "okay don't evacuate flight attendants, do not evacuate" to which the first officer responded "oh they are already going."
Review of Air Traffic records and interviews with controllers revealed that about 30 minutes prior to the accident the taxiway lights for "TWY J & Apron 2" were selected "off." This resulted in shutting off the lights for taxiways L and J; taxiways T4 and T5 to the northeast of L; the lights along the edge of the ramp parallel to J; and the connector and circular area between Concourses B and C.
PROBABLE CAUSE: "The flight crew's early turn towards the assigned gate because taxiway lighting had been inadvertently turned off by the controller-in-charge which resulted in the airplane leaving the paved surface.
Contributing to the accident was the operation of the screen-saver function on the lighting control panel that prevented the tower controllers from having an immediate visual reference to the status of the airfield lighting."
METAR:
22:53 UTC / 16:53 local time:
KBNA 152253Z 18003KT 10SM CLR 17/07 A2989 RMK AO2 SLP121 T01670072
23:53 UTC / 17:53 local time:
KBNA 152353Z 00000KT 10SM CLR 14/07 A2989 RMK AO2 SLP122 T01440067 10200 20144 50002
Accident investigation:
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Investigating agency: | NTSB |
Report number: | DCA16LA032 |
Status: | Investigation completed |
Duration: | 1 year 1 month |
Download report: | Final report |
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Sources:
NTSB Flightradar24 Location
Images:
photo (c) NTSB; Nashville International Airport, TN (BNA); 15 December 2015; (publicdomain)
photo (c) NTSB; Nashville International Airport, TN (BNA); December 2015; (publicdomain)
photo (c) NTSB; Nashville International Airport, TN (BNA); December 2015; (publicdomain)
photo (c) NTSB; Nashville International Airport, TN (BNA); 15 December 2015; (publicdomain)
Revision history:
Date/time | Contributor | Updates |