Go Back  PPRuNe Forums > Flight Deck Forums > Rumours & News
Reload this Page >

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

Rumours & News Reporting Points that may affect our jobs or lives as professional pilots. Also, items that may be of interest to professional pilots.

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

Old 15th Aug 2018, 22:34
  #21 (permalink)  
 
Join Date: Jan 2008
Location: Herts, UK
Posts: 747
Originally Posted by er340790 View Post
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.
haha.. double my weight !
HarryMann is offline  
Old 15th Aug 2018, 23:24
  #22 (permalink)  
 
Join Date: Dec 2001
Location: FL, USA
Posts: 2,738
Iím thinking maybe a configuration change in number of Economy class seats, Preferred seats and whatever else they call them.
B2N2 is offline  
Old 16th Aug 2018, 08:36
  #23 (permalink)  
 
Join Date: Aug 1999
Location: Hyeres, France
Posts: 0
Originally Posted by KenV View Post
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.
It was just a thought about the ex-AirTran aircraft....

I think the discussion about the Irish VLCC was something along the lines of as long as they were flying comparatively shorter stage lengths and so were rarely carrying full fuel then it could be that the aircraft never departed at the manufacturer's MTOW....Or something like that....

But as I said, just a thought...

.
Hussar 54 is offline  
Old 16th Aug 2018, 13:17
  #24 (permalink)  
txl
 
Join Date: Jan 2008
Location: Berlin
Age: 53
Posts: 86
Interested PAX here. I always wondered what the average figures for calculating passenger weight are. Is that a global standard?
txl is offline  
Old 16th Aug 2018, 16:03
  #25 (permalink)  
Thread Starter
 
Join Date: Aug 2013
Location: PA
Age: 56
Posts: 31
Aviation Watchdog Investigating FAA Oversight of Southwest Airlines
underfire is offline  
Old 16th Aug 2018, 23:32
  #26 (permalink)  
 
Join Date: Mar 2015
Location: North by Northwest
Posts: 476
Originally Posted by B2N2 View Post
Iím thinking maybe a configuration change in number of Economy class seats, Preferred seats and whatever else they call them.
Or maybe had to relocate a few to accommodate mini horses as service animals as announced today.....
b1lanc is offline  
Old 17th Aug 2018, 02:22
  #27 (permalink)  
 
Join Date: Nov 2007
Location: Texas
Posts: 1,853
Originally Posted by txl View Post
Interested PAX here. I always wondered what the average figures for calculating passenger weight are. Is that a global standard?
In the USA it's 190 pounds in the summer and 195 in the winter. There are separate male/female numbers of 200/205 and 179/184 but everyone I know just uses the average. Children up to 12 are 82/87 but most times they are just counted at 190/195 also. Sometimes when trying to carry a jumpseating crewmember on a weight restricted flight I've heard Captains asking if any of the pax are children. Two kinder would allow the jumpseater.

No idea if the numbers are standard around the world. The FAA raised the numbers several years ago after a Beech 1900 crash in CLT. They said they would monitor American weights and adjust as necessary.
MarkerInbound is offline  
Old 19th Aug 2018, 04:35
  #28 (permalink)  
 
Join Date: Feb 2008
Location: Dubai
Posts: 78
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 ?
There is another European LCC who does/did this. Not sure about a previous discussion, but they registered lower Max weights for the fleet. The weight of the aircraft was what it weighed but the max payload was reduced. From memory, the structural limit was around 71T, one group reduced to around 64T, another to around 62.5T and some more to around 60.5T. No idea of the saving it generated but with large fleets, even small amounts will help and go straight to the bottom line.
groundagent is offline  
Old 19th Aug 2018, 05:11
  #29 (permalink)  
 
Join Date: Jul 2004
Location: Netherlands
Posts: 696
Lowering the max TOW is standard practise at klm as well. There are scores of 737ís with a max tow of either 70t, 71t, 72t, instead of the official 73,8t. (-800)
or 61t for the 737-700, which is officially 64.something. Saves a huge amount of hard cash.
not only RYR does that.
fox niner is offline  
Old 19th Aug 2018, 11:37
  #30 (permalink)  
 
Join Date: Mar 2018
Location: Central UK
Posts: 560
A few years back one of the UK locos ran an exercise to check the accuracy of their weights. Aircraft were weighed in the hangar during maintenance to verify actual weight against the recorded figures and also selected at random as they entered the apron after a flight and directed onto a stand equipped with pressure pads. They were marshalled carefully onto the three pads and after about a minute, if even that, were able to disembark pax normally. Results were correlated with the flight papaerwork and processed.

Results showd the standard weights used were remarkably good, iirc something like a 2-300Kg deviation from the paper figure which on a 60t aeroplane is extremely accurate.
meleagertoo is offline  
Old 15th Oct 2020, 18:27
  #31 (permalink)  
 
Join Date: Aug 2020
Location: Far East
Posts: 38
Southwest 737 Short Grounding in September

Temporary grounding of 115 737-800 at Southwest took place due to weight difference of 75lbs in IT vs. actual mass. Took some days until half of the fleet returned to service. Reported to be a difference <0.05% of MTOW.

from aero international magazine

Safety matters, but isn't this a bit surprising?
waito is offline  
Old 16th Oct 2020, 10:28
  #32 (permalink)  
 
Join Date: Sep 2008
Location: Where it is comfortable...
Age: 57
Posts: 802
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 ?
This works primarily in Europe, where landing fees and Eurocontrol charges are all driven by a MTOW based formula. In the US these charges are per movement or category based, so playing with the weight figures for a given aircraft model has no effect on operating costs.
andrasz is offline  
Old 16th Oct 2020, 10:56
  #33 (permalink)  
 
Join Date: Mar 2005
Location: UK
Posts: 547
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).
Would it not make sense for the flight crew to complete their own weight and balance calculation using an EFB or similar device? This way the airline can ensure that they have up to date records of their own fleet weights without having to worry about disseminating the information to all of their handling agents and auditing it. The handling agent present a loading form with passenger weights, distribution and load in compartments for the flight crew to enter into their own EFB. Similar devices are used for computing takeoff performance, surely adding a WB function wouldn't be too difficult?
TotalBeginner is offline  
Old 16th Oct 2020, 17:38
  #34 (permalink)  
 
Join Date: Apr 2006
Location: uk
Posts: 907
Ummm...isn't that the point of using an average weight? If 50% are over the average, the other 50% can only be less than the average. So all is OK.

Just sayin'.

The real problem is that frequently it's not 50% who are fatties and over the assumed average weight, it's 80%, especially when they lug on board 25 Kg of "cabin baggage" that no aircraft is designed to accommodate.

old,not bold is offline  
Old 17th Oct 2020, 13:00
  #35 (permalink)  
 
Join Date: Dec 2011
Location: UK
Posts: 833
Originally Posted by fox niner View Post
Lowering the max TOW is standard practise at klm as well. There are scores of 737ís with a max tow of either 70t, 71t, 72t, instead of the official 73,8t. (-800)
or 61t for the 737-700, which is officially 64.something. Saves a huge amount of hard cash.
not only RYR does that.
And its not just in Europe. The AFM will likely show 70,999 or 71,999 for instance. This is not an unusual occurrence.
On the Airbus, you have multiple WVs.
Dannyboy39 is offline  
Old 17th Oct 2020, 15:07
  #36 (permalink)  
 
Join Date: Jun 2002
Location: CEH2 (Black Diamond, Alberta)
Posts: 5,616
Originally Posted by txl View Post
Interested PAX here. I always wondered what the average figures for calculating passenger weight are. Is that a global standard?
Here are the numbers for Canada. Note that the adult weights in the table include a 13 lb allowance for carry-on:



https://tc.canada.ca/en/aviation/ref...-ac-no-700-022
India Four Two is offline  
Old 18th Oct 2020, 18:34
  #37 (permalink)  
 
Join Date: Nov 2007
Location: Texas
Posts: 1,853
andrasz

Had some 727s at an old job, exNW airframe converted freighters, the landing weight had purposely been lowered to reduce the landing fee paid. We sent a check to Boeing and in a few weeks had new placards raising the max landing weight 4000 pounds.
MarkerInbound is offline  
Old 19th Oct 2020, 16:59
  #38 (permalink)  
 
Join Date: Jul 2009
Location: USA
Age: 75
Posts: 131
I remember several years back taking a co-worker to the airport for a flight to Sydney on a very small airline. Earlier that year they had experienced a fatal crash. One thing I had never seen before was weighing each passenger and when everyone was checked in, assigning seats. Second was that the pilot got a fuel sample from the fueling truck, took it into a back room, and after a few minutes came out and gave the fueler the okay to proceed. Too bad it took a crash to tidy things up.
NWA SLF is offline  
Old 20th Oct 2020, 09:40
  #39 (permalink)  
 
Join Date: Jun 2001
Location: UTC +8
Posts: 2,626
It's hard to imagine taking 66 jets abruptly off the line when as many available jets are roosting in the sun at VCV, plus the now recertified 34 Max jets.
GlueBall is offline  
Old 20th Oct 2020, 10:46
  #40 (permalink)  
 
Join Date: Jun 2001
Location: Intentionally Left Blank
Posts: 379
txl No here is not a global standard; there are 'regulator' standards and should an airline choose to do so, they can seek approval for their own standard passenger and baggage weights. There is a strict process and mathematical model behind the derivation of the standard weights published, used and approved. Typically they are derived from a study of real passengers (actually weighing many hundreds if not thousands across a population at the aircraft side, including all hand baggage) and the numbers run through standardisation methodologies with a confidence interval of 98%. Meaning that the average weights applied for Male, Female, Child and Infant (including hand baggage) is accurate to within +/- 1%. Same for those that use a standard, as opposed to actual, baggage weight for mass and balance calculations prior to a flight departure.

Last edited by Icarus; 21st Oct 2020 at 01:28.
Icarus is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.