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Southwest Airlines suddenly grounds scores of planes due to aircraft weight issues

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Southwest Airlines suddenly grounds scores of planes due to aircraft weight issues

Old 14th Aug 2018, 15:43
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Southwest Airlines suddenly grounds scores of planes due to aircraft weight issues

How does this happen and what the heck does it really mean?

"Southwest Airlines abruptly grounded 66 Boeing 737 aircraft in its fleet last Wednesday after issues with the carrierís aircraft weight records were discovered.
In an internal memo to employees on the matter that was obtained by the Chicago Business Journal, Southwest said: ďToday (Wednesday) we discovered the weights being sent to our Dispatch Operation did not match our other weight records for a number of aircraft in the fleet. As a result, and out of an abundance of caution, we have stopped flying those aircraft to recalculate the weights of the aircraft in question and reset the program.Ē
Aircraft weight is important because dispatch personnel and pilots need the correct information to determine the amount of fuel to load and other data needed to safely operate a flight."

https://www.bizjournals.com/chicago/...hoo&yptr=yahoo
underfire is offline  
Old 14th Aug 2018, 15:59
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Erm, go with the higher weight from the two sources and operate with reduced passengers loads until the data issue is resolved? Any safety reports to suggest this is a serious airworthiness issue?
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Old 14th Aug 2018, 16:21
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Mnnh - SWA, particulary with regards to aircraft records, is getting "the fisheye" from the FAA at the moment. As well as a lawsuit, both stemming from the fatal engine explosion near Philly. A time to make sure all the i's are dotted and t's crossed.

And the backstory is, the FAA itself is getting some flak and oversight (IG investigation) for perhaps being too "chummy" with operators.

"An abundance of caution," as the memo states.

As to how it happens - weight may "accrete" on an air frame, as things like passenger wi-fi, or even flight systems, get added or upgraded (or even removed). And maybe not all departments "get the memo" of the change to aircraft N000SW's weight, so the records don't match. Big corporate bureaucracy (or perhaps too small and overworked a corporate bureaucracy).
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Old 14th Aug 2018, 16:23
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It's possible the higher of the 2 weights may also be incorrect.

Sensible to ground the aircraft as a precaution imho.
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Old 14th Aug 2018, 16:35
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Originally Posted by pattern_is_full View Post
And the backstory is, the FAA itself is getting some flak and oversight (IG investigation) for perhaps being too "chummy" with operators.
Some things never change. Shortly after the Decmeber 1, 1974, TWA 514 CFIT, TWA's POI was transferred. Rumor had it that he was too chummy with TWA's flight ops management.
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Old 14th Aug 2018, 16:41
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either it meets the FARs or not, "chummy" has nothing to do with it, except for how long it was out.

Of course the bigger issue is what went wrong in the process at SW end..
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Old 14th Aug 2018, 16:41
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...with the merger between Southwest and airTran, airTran had 66+ B737-700's in their fleet.
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Old 14th Aug 2018, 17:03
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Lomapaseo

Well, "chummy" can mean the local FAA guy him(her)self doesn't cross-reference all the weights on file: in the onboard W&B paperwork; in the airframe's FMS; in dispatch's paperwork; in the maintenance records; in the master file at HQ. Never assume that even "good guys" can't get a little lax, now and then, trusting the operator's processes because they are also "good guys/gals."

I'm not knocking either the FAA or SWA (for whom the fatal event was their first (onboard, aircraft failure) in 51 years) particularly - human mistakes can creep in anywhere. You catch 'em, you tighten ship.
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Old 14th Aug 2018, 17:53
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I am convinced the biggest risk on aircraft weight remains the under-calculation of pax + carry ons. This despite the recent mandated FAA et al increases.

In 2013 the H&S dept of our N. Canada mining operations did a full verification of our rotational personnel. Yes, these flights were over 80% male and miners are probably larger than the average male, but....

The result???

Summer 278 lbs.

Winter 291 lbs.

Enter those kind of figs into the last Weight & Balance you personally calculated and you'll see where I'm coming from.
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Old 14th Aug 2018, 18:00
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Is this related to the issue of fleet weights discussed recently in Tech Log?
changing registration on Loadsheet....
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Old 14th Aug 2018, 18:34
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Originally Posted by Bigpants View Post
Erm, go with the higher weight from the two sources and operate with reduced passengers loads until the data issue is resolved? Any safety reports to suggest this is a serious airworthiness issue?
Legally you are not allowed to despatch an aircraft without knowing the correct weight. As they cannot determine which record is correct, if any, then they had no other option.
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Old 14th Aug 2018, 22:22
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Classic example of the 'Normalisation of Deviance'. Best to stop because, irrespective of the laws quoted above, losing a single pax life is not good for anyone.
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Old 15th Aug 2018, 02:21
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Its not only the weights, the weight document from technical services will also indicate the centre of gravity (basic index) which the starting point to calculate the aircraft CG and have %MAC.
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Old 15th Aug 2018, 02:33
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Originally Posted by Eric Janson View Post

Sensible to ground the aircraft as a precaution imho.
I beg to differ.
Itís nothing but an excercise in paperwork.
Amd Iíll tell you why it doesnít matter.
íStandardí FAA passenger weights have left the realm of reality long time ago.
Even with everything averaged at least 50% of pax exceed their allotted weight.
So on a full airplane load letís say 70 pax exceed by an average of 20lbs that means W&B is already 1400lbs off. Add to that the fact that carry on is not weighed and youíre already passed 2000 lbs.
What may have happened on some of the airplanes is that seat configurations were changed and maybe not noted.
In any case the airplanes could just as well be lighter then the paperwork says they are.
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Old 15th Aug 2018, 06:04
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Just to clarify, paperwork errors make the airplane 100% illegal to fly while it is still 100% safe to fly.
Because youíre already 3000lbs off to begin with...and thatís on a good day.
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Old 15th Aug 2018, 06:32
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Underfire - I'm pretty much with you. Gallup reports that U.S. men self-reported weights that averaged out to 191 lbs (women, 159 lbs). One may think that even those are low (due to vanity) but the same groups reported that their ideal weight would be about 20 lbs less (they were honest enough to admit they were a bit - chubby). 25% of men admitted to 200+ lbs; 29% of women admitted to 175-200+ lbs.

So the FAA numbers are about right - IF one excludes clothes and carryons, and only counts flesh. And 20 pounds shy with those added (in my case, the real extra weights are below the assumptions most of the time, if not, sadly, the body weight I weighed my winter overcoat - 3 lbs)

OTOH, let's take, oh, a nice average 737-800 with 2-class seating. 160 people plus babes-in-arms and crew = 180 x 20 = 3600 lb error. Given a MTOW for the 738 of 174,200 lbs, that is a 2% error. 157 feet/50 m on a nominal MTOW takeoff run, negligible in terms of exceeding MTOW unless one habitually flies with full tanks.

Redo the math as needed, for an Islander or an A380.

Nevertheless, I'm all for some updated statistics from which to "average."
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Old 15th Aug 2018, 15:56
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Originally Posted by fokkerjet View Post
...with the merger between Southwest and airTran, airTran had 66+ B737-700's in their fleet.
This is the most interesting and potentially apposite comment so far. Perhaps Air Tran methods/standards were different and when put into the SWA system the calculations did not work. A simple ontological problem could cause that if there is no Boeing standard.
Ian W is offline  
Old 15th Aug 2018, 16:19
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Originally Posted by fokkerjet View Post
...with the merger between Southwest and airTran, airTran had 66+ B737-700's in their fleet.
Of which SWA inherited 52, I believe, so that doesn't account for all of the 66 grounded 737s.
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Old 15th Aug 2018, 16:36
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Did we not have a discussion on here a couple of years ago about the Irish VLCC ' gaining advantage ' by registering some / all its fleet with lower gross weights in order to benefit from lower En Route Charges from Eurocontrol ?

Something similar at Southwest, perhaps ?
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Old 15th Aug 2018, 19:32
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Originally Posted by Hussar 54 View Post
Did we not have a discussion on here a couple of years ago about the Irish VLCC ' gaining advantage ' by registering some / all its fleet with lower gross weights in order to benefit from lower En Route Charges from Eurocontrol ?
Something similar at Southwest, perhaps ?
Really? They did it on purpose to "gain an advantage" with 66 out of over 700 of their aircraft and then suddenly changed their mind and grounded those aircraft? Excuse me if I sound a bit incredulous.
KenV is offline  

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