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Automatic Weight & Balance Calc Device  
User currently offlineredflyer From United States of America, joined Feb 2005, 4315 posts, RR: 28
Posted (3 years 3 weeks 4 days 4 hours ago) and read 3460 times:

I recall a couple of years ago after the EK A340 tail strike in Australia there was some discussion around why an automatic device couldn't be implemented to prevent just such an occurrence. It appears Boeing has just patented such a device. Now we need to see if it can be put to practical use.

http://patft.uspto.gov/netacgi/nph-P...44.PN.&OS=PN/7967244&RS=PN/7967244


I'm not a racist...I hate Biden, too.
16 replies: All unread, jump to last
 
User currently offlinepilotpip From United States of America, joined Sep 2003, 3148 posts, RR: 11
Reply 1, posted (3 years 3 weeks 4 days 4 hours ago) and read 3451 times:

We've been doing ours via ACARS for 3 years. To put some sort of sensors on the aircraft, while patented is likely impractical.


DMI
User currently offlineyeelep From United States of America, joined Apr 2011, 649 posts, RR: 0
Reply 2, posted (3 years 3 weeks 4 days 2 hours ago) and read 3431 times:

May be impractical as a retrofit, due to wiring, but on a new aircraft it wouldn't. I imagine it would be offered as a option if it ever is introduced.

User currently offlineredflyer From United States of America, joined Feb 2005, 4315 posts, RR: 28
Reply 3, posted (3 years 3 weeks 4 days 1 hour ago) and read 3422 times:

Quoting yeelep (Reply 2):
I imagine it would be offered as a option if it ever is introduced.

And if it is ever introduced, my guess is it will be used only as a verification/sanity check.



I'm not a racist...I hate Biden, too.
User currently offlineB747FE From Hong Kong, joined Jun 2004, 230 posts, RR: 4
Reply 4, posted (3 years 3 weeks 3 days 19 hours ago) and read 3356 times:

Looks like an upgrade of what has already been in use for many years.

Installed Weight Scales.. (by SunriseValley Mar 3 2005 in Tech Ops)?threadid=111949&searchid=112043&s=weight+scales#ID112043

Regards,
B747FE.



"Flying is more than a sport and more than a job; flying is pure passion and desire, which fill a lifetime"
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 5, posted (3 years 3 weeks 3 days 19 hours ago) and read 3350 times:

Quoting redflyer (Thread starter):
I recall a couple of years ago after the EK A340 tail strike in Australia there was some discussion around why an automatic device couldn't be implemented to prevent just such an occurrence. It appears Boeing has just patented such a device. Now we need to see if it can be put to practical use.


An on-board weight and balance system was an option on the L-1011 in the 1970's. Saudia was the only operator that choose the option and it was removed after only a very short time in service, as it provide to be quite failure prone!


User currently offlineJoeCanuck From Canada, joined Dec 2005, 5405 posts, RR: 30
Reply 6, posted (3 years 3 weeks 3 days 16 hours ago) and read 3326 times:

It reminds me of the rough load calculations that can be made from checking the pressure in the suspension air bags on a big rig and trailer.

Electronic load cells are so reliable and small that it's amazing that it's taking this long to get them on planes. It wouldn't be difficult to beat the accuracy of the current system...especially for passengers.



What the...?
User currently offlinewilco737 From Greenland, joined Jun 2004, 8968 posts, RR: 76
Reply 7, posted (3 years 3 weeks 3 days 15 hours ago) and read 3317 times:
AIRLINERS.NET CREW
HEAD MODERATOR

The 747 has a simple system installed already. It won't give you exact trim and weight, but it is a form of check there.
If you enter a very aft CG into the FMS, but the real CG is far in the front and the nose gear is compressed, the airplane gives you an error message. Same happens the other way around as well.

Problem with these automatically weight is when it is snowing or raining or ice is on the airplane. The airplane then is a lot heavier than expected and the sensor would measuer that as well.

wilco737
  



It it's not Boeing, I am not going.
User currently offlineMir From United States of America, joined Jan 2004, 21525 posts, RR: 55
Reply 8, posted (3 years 3 weeks 3 days 15 hours ago) and read 3311 times:

Quoting wilco737 (Reply 7):
Problem with these automatically weight is when it is snowing or raining or ice is on the airplane. The airplane then is a lot heavier than expected and the sensor would measuer that as well.

And anti-ice fluid, I'd imagine.

-Mir



7 billion, one nation, imagination...it's a beautiful day
User currently offlinewilco737 From Greenland, joined Jun 2004, 8968 posts, RR: 76
Reply 9, posted (3 years 3 weeks 3 days 15 hours ago) and read 3310 times:
AIRLINERS.NET CREW
HEAD MODERATOR

Quoting Mir (Reply 8):
And anti-ice fluid, I'd imagine.

Yes, every additional substance (snow, ice, anti- ice fluid, rain...) on the airplane makes the airplane heavier...

wilco737
  



It it's not Boeing, I am not going.
User currently offlineJoeCanuck From Canada, joined Dec 2005, 5405 posts, RR: 30
Reply 10, posted (3 years 3 weeks 1 day 14 hours ago) and read 3117 times:

Quoting wilco737 (Reply 9):
Yes, every additional substance (snow, ice, anti- ice fluid, rain...) on the airplane makes the airplane heavier...

Is that really such a bad thing? I would venture a guess that the vast majority of flights will not be encumbered by snow and except for those rare occasions, load sensors would seem to me to be a reliable tool.



What the...?
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 11, posted (3 years 3 weeks 16 hours ago) and read 3030 times:

Quoting JoeCanuck (Reply 10):
I would venture a guess that the vast majority of flights will not be encumbered by snow and except for those rare occasions, load sensors would seem to me to be a reliable tool.

The problem is that the load sensors that are really simple and don't introduce a new failure path aren't that accurate, and the ones that are really accurate introduce weigh, complexity, and (most importantly) a new load path. Yes, it would be nice to have, and it's offered on some jets where it really matters (mostly freighters) but, in the vast majority of cases, it's not worth the headache.

Tom.


User currently offlinebond007 From United States of America, joined Mar 2005, 5398 posts, RR: 8
Reply 12, posted (3 years 3 weeks 10 hours ago) and read 3014 times:

Quoting tdscanuck (Reply 11):
aren't that accurate


Agreed, but is that lack of accuracy relative to the accuracy of load sensors as a whole, or relative to the accuracy to what we calculate the CG and W&B to the majority of the time?


Jimbo



I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!
User currently offlineJoeCanuck From Canada, joined Dec 2005, 5405 posts, RR: 30
Reply 13, posted (3 years 2 weeks 5 days 14 hours ago) and read 2918 times:

Accurate, reliable and portable load sensors have been available to the trucing industry and regulators for decades. I see the problem of implementation to be more of avoiding the expense, time and pain of certifying the devices for commercial flying use than their lack of accuracy.

If not installed on the plane, load sensor pads could be set up at the gates, either permanent or portable. Or set up on the taxiway. A vehicle doesn't have to completely stop to get an accurate weight measurement.

I have no doubt that a properly calibrated load sensor would be significantly more accurate than the current weight guesstimates of passengers.



What the...?
User currently offlinejetlagged From United Kingdom, joined Jan 2005, 2543 posts, RR: 24
Reply 14, posted (3 years 2 weeks 1 day 23 hours ago) and read 2765 times:

Quoting wilco737 (Reply 7):
The 747 has a simple system installed already. It won't give you exact trim and weight, but it is a form of check there.
If you enter a very aft CG into the FMS, but the real CG is far in the front and the nose gear is compressed, the airplane gives you an error message. Same happens the other way around as well

As an option, 744s have a weight and balance system installed which will calculate gross weight and CG and present those on the FMS PERF INIT page for the crew to either accept, or enter values from the loadsheet.



The glass isn't half empty, or half full, it's twice as big as it needs to be.
User currently offlineKAUSpilot From United States of America, joined Jan 2002, 1958 posts, RR: 33
Reply 15, posted (3 years 2 weeks 1 day 10 hours ago) and read 2748 times:

The 744 freighters I fly have a gross weight and CG readout on the main deck just forward of the L1 door, near the nose cargo door control panel. In addition, I have flown some 744 BCF's which give a gross weight readout on the upper EICAS display in the flight deck. I was told that the airplane computes this by measuring the compression of the nose gear strut, although I'm sure it's more complex than that.

Even though the plane calculates these weights on its own, we still use separate, computer generated weight and balance manifests to calculate aircraft performance and generate takeoff speeds. In my experience (and I'm still very new to the airplane), the airplane's readout and the computer generated manifest have usually been within a few percentage points of each other.


User currently offlinejetlagged From United Kingdom, joined Jan 2005, 2543 posts, RR: 24
Reply 16, posted (3 years 2 weeks 1 day 2 hours ago) and read 2706 times:

Quoting KAUSpilot (Reply 15):
The 744 freighters I fly have a gross weight and CG readout on the main deck just forward of the L1 door, near the nose cargo door control panel. In addition, I have flown some 744 BCF's which give a gross weight readout on the upper EICAS display in the flight deck. I was told that the airplane computes this by measuring the compression of the nose gear strut, although I'm sure it's more complex than that.

Once the FMC has a gross weight and CG initialised (either from the loadsheet or via the WBS, if installed) that is the basis for all weight and CG calculations in flight. The only thing which varies in flight is fuel weight and CG, so the FMC can compute changes in gross weight and CG as a result of fuel usage.



The glass isn't half empty, or half full, it's twice as big as it needs to be.
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