Southwest Midway incident update

[Bucky]

http://news.yahoo.com/s/nm/20060620/us_nm/airlines_southwest_runway_dc

Excerpts:

"Veteran Capt. Bruce Sutherland and first officer Steven Oliver decided
to bring the Boeing 737 down on December 8 despite snow, conflicting
reports on runway conditions, and their initial indecision about using
the aircraft's automatic braking system, which could mean a more abrupt
stop... Sutherland felt he was not familiar enough with the enhanced
braking system to use it in bad weather and the two spent a long time
reviewing calculations to see if they could land safely in Chicago...
The safety board has been looking at when the pilots activated the
engine thrust reversers, which help slow a plane once it's down. They
were turned on 18 seconds after touchdown; Four or five seconds is
common."

[Jay Beckman]

"Bucky" > wrote in message
oups.com...
> http://news.yahoo.com/s/nm/20060620/us_nm/airlines_southwest_runway_dc
>
> Excerpts:
>
> "Veteran Capt. Bruce Sutherland and first officer Steven Oliver decided
> to bring the Boeing 737 down on December 8 despite snow, conflicting
> reports on runway conditions, and their initial indecision about using
> the aircraft's automatic braking system, which could mean a more abrupt
> stop... Sutherland felt he was not familiar enough with the enhanced
> braking system to use it in bad weather and the two spent a long time
> reviewing calculations to see if they could land safely in Chicago...
> The safety board has been looking at when the pilots activated the
> engine thrust reversers, which help slow a plane once it's down. They
> were turned on 18 seconds after touchdown; Four or five seconds is
> common."
>

I believe this last sentence does not accurately explain what may have
happened.

The thrust reversers did not *deploy* until sometime after touchdown
(possibly due to lack of wheel spin up.) This does not mean they weren't
"selected/activated" ASAP on landing.

Jay B

[[email protected]]

Bucky wrote:
> http://news.yahoo.com/s/nm/20060620/us_nm/airlines_southwest_runway_dc
>
> Excerpts:
>
> "Veteran Capt. Bruce Sutherland and first officer Steven Oliver decided
> to bring the Boeing 737 down on December 8 despite snow, conflicting
> reports on runway conditions, and their initial indecision about using
> the aircraft's automatic braking system, which could mean a more abrupt
> stop... Sutherland felt he was not familiar enough with the enhanced
> braking system to use it in bad weather and the two spent a long time
> reviewing calculations to see if they could land safely in Chicago...
> The safety board has been looking at when the pilots activated the
> engine thrust reversers, which help slow a plane once it's down. They
> were turned on 18 seconds after touchdown; Four or five seconds is
> common."

News reports also stated they decided against diverting to STL,
which would have incurred various extra costs. I hope that
SWA doesn't apply pressure to avoid diverting due to $$.

Returning from HNL once, I landed at ORD (UAL mileage plus award)
rest of group due at MDW on ATA got diverted to Indy during a storm.

JG

[Robert M. Gary]

wrote:
> News reports also stated they decided against diverting to STL,
> which would have incurred various extra costs. I hope that
> SWA doesn't apply pressure to avoid diverting due to $$.

Only as a result of mechanical failure. The airline does not accept any
cost or provide any accomidations for changes in the flight as a result
of weather.

-Robert

[[email protected]]

Jay Beckman wrote:

> > The safety board has been looking at when the pilots activated the
> > engine thrust reversers, which help slow a plane once it's down. They
> > were turned on 18 seconds after touchdown; Four or five seconds is
> > common."
> >
>
> I believe this last sentence does not accurately explain what may have
> happened.
>
> The thrust reversers did not *deploy* until sometime after touchdown
> (possibly due to lack of wheel spin up.) This does not mean they weren't
> "selected/activated" ASAP on landing.
>
> Jay B


If I'm not wrong, it's a requirement that reversers aren't deployed
until the plane is firmly on the ground (to probably preclude unwanted
torquey stresses on the landing gear due to asynchronous spooling,
should it occur), and that may have had a bearing on when the pilots
chose to activate them. I also recollect reading somewhere that you're
barred from using reversers if there's a tailwind of 10 kts or more, or
when the touchdown speed is too high (can't think of a reason why that
should be so).

The reversers not deploying despite being activated much earlier might
not be very probable. I say that because 737 isn't yet fly-by-wire
where the automation systems augment/refine and even override pilot
input (remember the Jo'burg runway overrun of an A340 in early '04?).

Ramapriya

[150flivver]

wrote:
> The reversers not deploying despite being activated much earlier might
> not be very probable. I say that because 737 isn't yet fly-by-wire
> where the automation systems augment/refine and even override pilot
> input (remember the Jo'burg runway overrun of an A340 in early '04?).
>
> Ramapriya

We've had squat switches "overriding" gear up commands for many years
before fly-by-wire. Seems to me not too difficult to design a thrust
reverser inhibit circuit based on wheel spin-up. I fail to see how all
this pure speculation on 737 system design sheds light on this
particular incident. I'll wait for the NTSB report, thank-you.

[Capt.Doug]

> wrote in message
> News reports also stated they decided against diverting to STL,
> which would have incurred various extra costs. I hope that
> SWA doesn't apply pressure to avoid diverting due to $$.

If SWA's pay scheme is similar to my employer's, the pilots would have made
more pay for diverting. We don't get a bonus for being on time (though our
gate agents do). I have never met an airline pilot who puts finances ahead
of safety. It's our professionalism that drives us to be on time.

D.