SWA off rwy at Nashville
So........did it slide off a taxiway or a runway, or did it just miss a turn and end up on the grass?
From the diagram in post 9 it doesn't look like it's slid off the runway at all.
From the diagram in post 9 it doesn't look like it's slid off the runway at all.
Nothing to do with a runway - journos just think any pavement at an airport is "runway." 
From the surveillance video - even with bits edited out - it does look like they were fooled by the doubled-up parallel taxiways into turning too soon onto what they thought was ramp, but was a second strip of grass. That is also a 2-meter hole in the ground!
But nothing (yet) rules out a wind gust or sudden tiller problem.
In this picture: https://c2.staticflickr.com/4/3071/2...34e02b9686.jpg
...the accident occured lower right, where the medium-gray taxiway meets the lighter ramp pavement. The fact that the "ramp"-colored pavement extends down the taxiway a little way could have contributed to confusion as to where the edge was - at dusk, and with a brightly-lit terminal in the background to suppress night vision.
I'll be interested to see what the final report says.
From the surveillance video - even with bits edited out - it does look like they were fooled by the doubled-up parallel taxiways into turning too soon onto what they thought was ramp, but was a second strip of grass. That is also a 2-meter hole in the ground!
But nothing (yet) rules out a wind gust or sudden tiller problem.
In this picture: https://c2.staticflickr.com/4/3071/2...34e02b9686.jpg
...the accident occured lower right, where the medium-gray taxiway meets the lighter ramp pavement. The fact that the "ramp"-colored pavement extends down the taxiway a little way could have contributed to confusion as to where the edge was - at dusk, and with a brightly-lit terminal in the background to suppress night vision.
I'll be interested to see what the final report says.
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Taxiway lighting problem at least in part. I suppose one could stop if they cant see where to go. And if you do decide to continue.....follow a yellow line, any yellow line religiously and fairly slowly. It probably won't go into the grass.
"Lights-Out Error Instigated Southwest Accident
WASHINGTON—Taxiway lights inadvertently turned off by an air traffic controller were a key factor in a December 2015 excursion of a Southwest Airlines Boeing 737-300 at the Nashville International Airport.
The pilots, partially blinded by terminal lights and without the guidance of taxiway centerline and edge lights, exited the pavement during a turn toward the terminal, and came to rest in a drainage ditch, collapsing the nose wheel, and damaging the fuselage and engines.
Contributing to the accident was a screen saver function on the touch-screen lighting-control panels in the air traffic control tower, which timed out and went blank after approximately 5 min. of inactivity. The blank screen prevented “the tower controllers from having an immediate visual reference to the status of the airfield lighting,” the NTSB said in its final report on the accident.
Nine of 138 passengers and crew on board the flight from Houston’s William P. Hobby Airport were injured during the evacuation in Nashville using escape slides, a process that was complicated by the blaring of a “gear unsafe” alarm in the cockpit. The NTSB said the horn “could not be silenced without disabling a circuit breaker or running a checklist procedure for an unrelated scenario.”
Due to the distraction caused by the alarm, the pilots did not communicate with flight attendants in the minutes after the excursion. According to the NTSB, flight attendants saw passengers “getting out of their seats” and “moving around the cabin,” and were unable to contact the pilots through the flight deck through the interphone (it was not powered) or knocking on the door, before starting the evacuation.
The evacuation was relatively orderly. However, the flight attendants noted in their written post-incident statements that some passengers took their purses, laptops, backpacks—and, in one case, a hanging clothes bag—down the escape slide.
Investigators found that controllers at the airport routinely shut off the taxiway centerline lights in the areas where the excursion took place, due to complaints from pilots about the brightness of the quartz-halogen bulbs. Controllers shut down the lights on the night of the incident, even though there had been no requests from pilots to do so.
About 30 min. before the accident, the controller-in-charge turned off the centerline lights, but also mistakenly turned off the taxiway edge lights in the area. Due to the screen saver function, controllers were then not aware of the status of the lights when the Southwest flight was taxiing to the gate.
Controllers told the NTSB that complaints about the centerline lights were a “common occurrence.” However, the NTSB found that the airport operator was not aware of the problem, and a review of the FAA’s air traffic safety action program database (a voluntary, non-punitive safety reporting system for controllers) revealed only one complaint.
“Neither the (air traffic control) staff nor airport operations personnel were aware that the centerline taxiway lights were quartz-halogen,” the NTSB said in the final report. “The fact that quartz-halogen lights were installed on the taxiway centerlines was provided by the airfield electrician during the group’s visit to the airfield lighting vaults.”
The NTSB did not issue any recommendations with the report.
https://www.ntsb.gov/_layouts/ntsb.a...16LA032&akey=1
"Lights-Out Error Instigated Southwest Accident
WASHINGTON—Taxiway lights inadvertently turned off by an air traffic controller were a key factor in a December 2015 excursion of a Southwest Airlines Boeing 737-300 at the Nashville International Airport.
The pilots, partially blinded by terminal lights and without the guidance of taxiway centerline and edge lights, exited the pavement during a turn toward the terminal, and came to rest in a drainage ditch, collapsing the nose wheel, and damaging the fuselage and engines.
Contributing to the accident was a screen saver function on the touch-screen lighting-control panels in the air traffic control tower, which timed out and went blank after approximately 5 min. of inactivity. The blank screen prevented “the tower controllers from having an immediate visual reference to the status of the airfield lighting,” the NTSB said in its final report on the accident.
Nine of 138 passengers and crew on board the flight from Houston’s William P. Hobby Airport were injured during the evacuation in Nashville using escape slides, a process that was complicated by the blaring of a “gear unsafe” alarm in the cockpit. The NTSB said the horn “could not be silenced without disabling a circuit breaker or running a checklist procedure for an unrelated scenario.”
Due to the distraction caused by the alarm, the pilots did not communicate with flight attendants in the minutes after the excursion. According to the NTSB, flight attendants saw passengers “getting out of their seats” and “moving around the cabin,” and were unable to contact the pilots through the flight deck through the interphone (it was not powered) or knocking on the door, before starting the evacuation.
The evacuation was relatively orderly. However, the flight attendants noted in their written post-incident statements that some passengers took their purses, laptops, backpacks—and, in one case, a hanging clothes bag—down the escape slide.
Investigators found that controllers at the airport routinely shut off the taxiway centerline lights in the areas where the excursion took place, due to complaints from pilots about the brightness of the quartz-halogen bulbs. Controllers shut down the lights on the night of the incident, even though there had been no requests from pilots to do so.
About 30 min. before the accident, the controller-in-charge turned off the centerline lights, but also mistakenly turned off the taxiway edge lights in the area. Due to the screen saver function, controllers were then not aware of the status of the lights when the Southwest flight was taxiing to the gate.
Controllers told the NTSB that complaints about the centerline lights were a “common occurrence.” However, the NTSB found that the airport operator was not aware of the problem, and a review of the FAA’s air traffic safety action program database (a voluntary, non-punitive safety reporting system for controllers) revealed only one complaint.
“Neither the (air traffic control) staff nor airport operations personnel were aware that the centerline taxiway lights were quartz-halogen,” the NTSB said in the final report. “The fact that quartz-halogen lights were installed on the taxiway centerlines was provided by the airfield electrician during the group’s visit to the airfield lighting vaults.”
The NTSB did not issue any recommendations with the report.
https://www.ntsb.gov/_layouts/ntsb.a...16LA032&akey=1
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OK... this is hindsight, but there's always something to learn from the misfortune of others.
#1: If you can't see, STOP. Don't plow on, swinging the nose to and fro trying to sniff out a dark taxiway. #2: If the taxi light isn't cutting it, turn those big, beautiful landing lights back on. #3: Taxiways are usually lit after dark. If yours isn't, refer to #1, and ask ground control why not. Doesn't matter how familiar you are with the airport.
It's so easy after the fact, isn't it
#1: If you can't see, STOP. Don't plow on, swinging the nose to and fro trying to sniff out a dark taxiway. #2: If the taxi light isn't cutting it, turn those big, beautiful landing lights back on. #3: Taxiways are usually lit after dark. If yours isn't, refer to #1, and ask ground control why not. Doesn't matter how familiar you are with the airport.
It's so easy after the fact, isn't it
It is a good reminder of all the points you just made.
On a broader note, we are starting to see a fair few incidents where 'modern technology' plays a role. Ie this screen saver and many other cases of OPT input or output errors that wouldn't happen with a book, phone and tablet battery fires, JeppFD-Pro timing out while on approach and probably many more. I am pro change and pro technology but I think we have to be pretty careful we don't get too relaxed about this sort of stuff and realise there are now holes in the cheese that only programmers could foresee.
On a broader note, we are starting to see a fair few incidents where 'modern technology' plays a role. Ie this screen saver and many other cases of OPT input or output errors that wouldn't happen with a book, phone and tablet battery fires, JeppFD-Pro timing out while on approach and probably many more. I am pro change and pro technology but I think we have to be pretty careful we don't get too relaxed about this sort of stuff and realise there are now holes in the cheese that only programmers could foresee.
