NTSB Rec - SWA 1248 at MDW

[viper548]

Do you have to arm the TR's on the 737 before they can be used?

 

[737tanker]

What do you make of the FO's statement in the above article? I am not being smart, I dont know the reverser system in the 73

From what we are unofficially hearing the F/O noticed that the reversers weren't deployed when the Capt said that he couldn't get the reversers deployed. To know for sure we will have to wait for the investigation to be completed. The CVR will show the investigators exactly what the Capt said, or didn't say.

 

[Say Again Over]

So to the fluf drivers, you land with low friction, auto-brakes armed, could this scenario somehow interfere with t/r deployment?

 

[Alin10123]

I've never flown a jet, but can't you do a go around after you touch down and find out R-thrust isn't working? Couldn't he have given her TO power and since they were already going at least 100 knots... they should have had more than enough runway to get up in the air again.

Not being a smartass or claim i know everything...just have a legitimate question.

 

[b82rez]

Once the autospoilers extend, a go-around usually isn't the best idea

 

[Alin10123]

Once the autospoilers extend, a go-around usually isn't the best idea

Couldn't they have put the spoilers down? Or would that have slowed them down enough to cut it close getting back up off the ground?

 

[Peanut gallery]

Right on

That, Gentlemen and Ladies, is why we have not been using any credit for reverse in computing landing distance since I've been flying reversible airplanes. That being since 1953.

I have no sympathy for Boeing, SWA or the FAA in deciding otherwise in the later 737's. It was bound to happen. I'd guess they will now pay.

DC

I can hardly believe that someone approved thrust reverse computations, this has been verboten since I started flying and now someone is smarter than the original certification standards. Unbelievable......

 

[9GClub]

I don't fly 737s, but it is my understanding that for the thrust reversers to deploy on that aircraft two conditions must be met to prevent inflight deployment:
-You must have Weight On Wheels &
-The wheel speed must be atleast 60kts
When the aircraft landed, the tires may not have spun up to 60kts because of the icy runway conditions. If that was the case, then they wouldn't have been able to deploy the TRs. Maybe that's what happened???

Yeah I'm a bit of an armchair jet pilot, but......

Geez, please tell me the wheel speed criterion isn't true. Assuming for the moment that it IS true, what's the point? A weight-on-wheels squat switch should be plenty.

Reverse never should have been included in landing data figures.....

It's a shame that accidents have to happen before this stuff gets straightened out.

 

[C40_Pilot]

Wheel speed 60 not true

"The thrust reverser can be deployed when either radio altimeter senses less than 10 feet altitude, or when the air/ground safety sensor is in the ground mode. Movement of the reverse thrust levers is mechanically restricted until the forward thrust levers are in the idle position."

Once the aircraft is on the ground and the throttles hit the idle stops, TR's can be operated.

A go around in those circumstances would be foolish. Keeping it on the deck was the right thing to do.

TR's on a 737-700 aren't armed. They are mechanically operated by the PF.

Spoilers are armed and operated automatically.

In the USAF, we have no "Good Reversers" or "Reverse Green" call. System is supposed to work as advertised.

Calculating landing data based on a system to slow you down once you touch down doesn't seem to whacked for me. If a carrier allows the use of TR's in its computations, its their call. Besides aren't the systems of each aircraft supposed to work?

Wow, for a board of professionals, some of the comments have not been.

 

[Alin10123]

Wow, for a board of professionals, some of the comments have not been.

Heck... i'm barely a 50 hr PP. So... it's ok if my comments were a little ... off...

 

[ultrarunner]

Sounds a little bit like the Captain could have forgotten the reversers, and the FO caught the error a little too late. At least after reading this NTSB report.

That's what I'm thinking or something similar. As when the FO grabbed the levers, the TR's ultimately did deploy. So the system was working at that point.

 

[ultrarunner]

Couldn't they have put the spoilers down? Or would that have slowed them down enough to cut it close getting back up off the ground?

Nope, they'd have had an even worse crash. Think about it. Touchdown at 140 kts or so, spoilers fire, engines at idle.

If you immediately initiate a bolter, by the time you stowed the spoilers and the engines came up to toga, the'd have prly been through the fence, and at a faster speed.

Better to have a car crash than a plane crash...

 

[[email protected]]

Good to know that what i heard about WOW and wheel speed was bogus info about 737....that seems like a poor design anyway.....
I was flying that night and ended up diverting to KDTW from our original destination KYIP. The weather was in fact really bad and the braking was reported as poor there as well as many other airports in the area. In addition to the poor braking at YIP there also would have been a significant crosswind on a slick runway....No thanks... Our pax were a little annoyed with our decision until they got to DTW and walked into the FBO and saw a Southwest airplane off the end of a runway on TV.....We then got thanked and commended...Even if we they were still mad with us....who cares? We weren't comfortable with going to YIP and i think the decision was a good one and a safe one. We both would have been comfortable explaining our decision.

 

[HawkerF/O]

Nope, they'd have had an even worse crash. Think about it. Touchdown at 140 kts or so, spoilers fire, engines at idle.

If you immediately initiate a bolter, by the time you stowed the spoilers and the engines came up to toga, the'd have prly been through the fence, and at a faster speed.

Better to have a car crash than a plane crash...

That is something with Boeing products that I never understood. If the spoilers are out, and power is added while not in reverse, then they should retract (slam down) without user input IF they were deployed from an "armed" status, not manually deployed. If they WERE manually deployed, a certain N1/EPR or throttle position should stow them automatically. Cali, Columbia in an AA757 should have taught them that. Except in Reverse and icing, and I'd like to think idle power in any Boeing would be enough to keep the wings clean, there is not a condition that calls for power to be added or maintained with spoilers extended. Even Challengers and Lears (older ones at that) auto-stow the spoilers when power not at idle if they are armed (deployed automatically). I'm sure there are other A/C types that do that as well.

As for the Call Outs; that is nothing but good cockpit management. If 1 T/R comes out and the other one does not, the PF should want to know about it instead of finding out by asysmetrics. Especially in a Xwind on a short runway, haul back on the T/Rs and 1 stays in, you may or may not know you ever had a problem without the call outs until you are off the side of the runway. The systems are supposed to work correctly, yes, but as we bare witness to in Chicago, that is simply not always the case.

 

[firstthird]

the spoilers do autostow if you add power.

We do touch and goes in the 737-700 (navy version C-40A) and you still arm the speed brakes before touchdown. once you are down, non-flying pilot puts the flaps to 15 and puts the trim back in the green. push the power levers up a little to get the speed brakes to stow, then up to 85% ish and at Vref, you rotate. works fine. There is a caveat though, if you do pop the reversers, you are stopping one way or the other, since it takes 3 seconds (or thereabouts) to restow the reversing sleeves.