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HAWK21M
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Overweight Taxi Condition

Mon Feb 02, 2004 5:03 pm

What are the conditions that one would be Taxiing at a weight that is more than the maximum-design-taxi-weight (MTW).
regds
HAWK
I may not win often, but I damn well never lose!!! ;)
 
UTA_flyinghigh
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RE: Overweight Taxi Condition

Mon Feb 02, 2004 5:59 pm

Dunno about MTW, but it is common procedure in airports with looong taxi/hold times for the crew to order extra fuel that actually places the aircraft over the MTOW (maximum take-off weight).
By the time the aircraft will be lined up and cleared for takeoff, the extra fuel will have been burnt off from the taxying/holding time.

Regards,
UTA
Fly to live, live to fly - Air France/KLM Flying Blue Platinum, BMI Diamond Club Gold, Emirates Skywards
 
FredT
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RE: Overweight Taxi Condition

Mon Feb 02, 2004 7:04 pm

Er... do you have evidence that this is done?

If it is a maximum weight, it is for a reason...

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
UTA_flyinghigh
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RE: Overweight Taxi Condition

Mon Feb 02, 2004 7:13 pm

I said MTOW, not max weight lol...
I shall (les Eaux) therefore look for evidence to substantiate my claims Big grin

UTA
Fly to live, live to fly - Air France/KLM Flying Blue Platinum, BMI Diamond Club Gold, Emirates Skywards
 
buckfifty
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RE: Overweight Taxi Condition

Mon Feb 02, 2004 7:24 pm

That's called MRW (Max Ramp Weight). However, if by the time you get to the threshold, and you are still over the MTOW, better turn on every appliance you got, and wait.

And I haven't heard of a single case where an aircraft would have taxiied with a weight greater than the MRW (or MTW, wherever that is used).

[Edited 2004-02-02 11:27:30]
 
411A
Posts: 1788
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RE: Overweight Taxi Condition

Mon Feb 02, 2004 11:13 pm

Recall in the early 1960's, BOAC started B707 ops from LAX nonstop to LHR.
At the time, this was the longest nonstop jet transport route, and the operation was very limiting. 25L/07R had to be the departure runway (longest runway at the time, 12,000 feet) and the departure was at 10pm to be sure the ambient temperature was low.
Several times the aircraft arrived at the runway, only to have to sit there for awhile, burning off excess taxi fuel.

Found out just why some years later when I was flying these same particular 707 (non-fan) models...very long takeoff runs were the norm, and initial climb rate especially low.
AF started nonstop ORY service shortly thereafter, and would be 15+ miles west before reaching 2000msl.
 
BMAbound
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Joined: Fri Nov 14, 2003 5:59 am

RE: Overweight Taxi Condition

Tue Feb 03, 2004 12:46 am

If my memory serves me correctly, the ramp weight of a C-172N is an enormous 7 lbs more than max take off weight.

Quite funny actually...

cheers

johan
Altitude is Insurance - Get Insured
 
flightsimfreak
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RE: Overweight Taxi Condition

Tue Feb 03, 2004 1:57 am

Where did you get that information, BMAbound? I looked in my 172N POH and the only referance to something similar to that came in section 5 saying that the total fuel for start, taxi, and takeoff is 1.1 gallons. I do not see anything that gives maximum taxi weight.
 
USAFHummer
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RE: Overweight Taxi Condition

Tue Feb 03, 2004 3:53 am

Here are the weights as listed from my Cessna 172S info manual:

Max Ramp Weight: 2558 lbs.
Max Takeoff Weight: 2550 lbs.
Max Landing Weight: 2550 lbs.

So with 100LL weighing about 6 lbs. per gallon, the aircraft needs to burn off 1.33 gallons of gas at max weight before it can t/o

Incidentally, just how much of a difference would those 8 lbs make if one tried to take off at max ramp weight? Is it really that significant?

Greg
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ben
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RE: Overweight Taxi Condition

Tue Feb 03, 2004 4:34 am

Incidentally, just how much of a difference would those 8 lbs make if one tried to take off at max ramp weight? Is it really that significant?

Probably not.. but that's a whole other can of worms. How big is the design safety margin? nobody but the designers know. Push it at your peril.

I doubt it would cause any problems, but if something did occur, it would invalidate the C of A and the insurance.

Light aircraft frequently operate over weight without any problems. To give you an idea of how 'accepted' it is, on my PPL skill test (we only have one skill test/check ride here, at the end) we were quite a bit over weight but the examiner gave me a symbolic weight to use for him, about half his real weight, just so the W&B calculation would work. So much for setting an example.
 
SkyGuy11
Posts: 532
Joined: Fri Oct 26, 2001 7:09 am

RE: Overweight Taxi Condition

Tue Feb 03, 2004 4:41 am

Flying overweight is not nearly as bad as flying out of CG limits; but it is the kind of thing where you don't know how much is too much until airborne... best to stick with the books.
.
 
BMAbound
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RE: Overweight Taxi Condition

Wed Feb 04, 2004 3:39 am

FlightSimFreak, on the very first page, where it says Performance and Specifications (looking at my POH for a 1979 C-172N), two Max weights are given, one for Ramp and one for T/O and landing.

best regards,

johan
Altitude is Insurance - Get Insured

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