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NTSB: Speedbrakes not armed before Southwest 737 excursion

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Dornier 335

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Aug 3, 2005
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Speedbrakes not armed before Southwest 737 excursion

2 hours ago

US investigators have determined that the speedbrakes on a Southwest Airlines Boeing 737-700 were not armed before the twinjet slid off the runway at Chicago Midway.

The crew did not deploy the thrust reversers until 16s after touchdown on runway 13C, which was damp as a result of rain showers.
In an update to the inquiry the National Transportation Safety Board says the braking action was reported as "fair" by a preceding Southwest 737 crew.

But it adds that flight recorder information shows the pilots of the incident flight did not arm the speedbrakes during preparations for arrival.
The crew had created extra workload by initially uploading and briefing the wrong approach procedure, and not realising the error until receiving clearance to leave the holding pattern and begin the approach to Midway.
Having reprogrammed the flight-management system for the correct approach, a recalculation indicated sufficient landing distance available. Runway 13C is 6,522ft (1,988m) long.

The crew correctly set the autobrake but the NTSB says the pilots experienced "additional operational distractions" during the final minutes of the approach, including a momentary flap overspeed.

This flap issue occurred at about the time that the before-landing checklist would normally have been performed - a checklist which includes arming of the speedbrakes.

But the NTSB says "no mention" of the checklist or the speedbrakes was found on the cockpit-voice recorder, and the flight-data recorder shows that the speedbrakes were not armed.

After touchdown the speedbrakes did not deploy and the thrust reversers were not activated. The captain "quickly" applied full manual braking after realising that the aircraft was not slowing as expected, says the NTSB, and reverse thrust was engaged with about 1,500ft of runway remaining - an action which automatically deployed the speedbrakes.

"As the airplane neared the end of the pavement, the captain attempted to turn onto the connecting taxiway but was unable," it states. The 737 hit a taxiway light and rolled 200ft into grass.

Without the speedbrakes' interruption of lift, the deceleration capability is "severely degraded", the NTSB says, because the braking effectiveness on the type is reduced by as much as 60%. Delay in the selection of reverse thrust also contributed to the amount of runway used.

Simulations determined that, had the speedbrakes deployed at touchdown,
the 737 would have stopped with 900ft of runway to spare - and as much as 1,950ft if the thrust reversers had been activated at the same time.
None of the 139 passengers and crew members was injured in the 26 April 2011 incident.


source
 
SWA guys, do you have ground callouts like "spoilers deployed", "reverse" by the pilot monitoring? Just wondering what your procedures are. Thanks.
 
SWA guys, do you have ground callouts like "spoilers deployed", "reverse" by the pilot monitoring? Just wondering what your procedures are. Thanks.

The american overrun in Jackson hole was pretty similar although more
Mechanically at fault. The PNF had made the deployed callout but the spoilers had not actually deployed.
 
Boeing factory SOP call "Speedbrake Up" or "Speedbrake Not Up" by PM on touchdown. Problem is that most Boeing operators have extensively modified the SOP's to their own liking. There is a school of thought that returning to factory SOP's is not a bad thing. However, very few operators are willing to do so.
 
It will be interesting to see if SWA incorporates the spoiler/no spoiler and reverse call that AirTan uses. I used to think it was a little redundant until reading this thread. Anyone can have a bad day. It really sucks when two people have a bad day. Even though something may not be SOP or on a checklist, if it's not doing what it's supposed to be doing, you can't be wrong for verbalizing it. SWA may or may not teach "5 green lights" coming over the fence, but I'll use it as long as I fly the 737.
 
They are in the process now to use the spoiler reverser calls. I think its BC Boeing uses it. A few people here already use the 5 green call. I just count 5 at 500ft.
 
Before landing:

"three-green" 'spoilers ARMED'

Touchdown:

"Spoilers UP" 'Two deploy'

Been working so far...

SOP change after AA at LIT
 

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