Questions tagged [weight-and-balance]

Weight-and-balance is determining that an aircraft is loaded within the limits of it's weight carrying capability and that the center of gravity is within the operational envelopes of the aircraft.

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54
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2answers
19k views

Is it possible to install a bike rack on a Cessna 172?

I stumbled upon a nice photo manipulation on aviationhumor.net. Source My question is short and concise: Is it practically possible to do that? Is it okay in terms of aerodynamics, weight, CG? ...
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8answers
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What if all passengers pay to check in extra baggage?

Suppose a given flight is fully booked and everybody shows up. Not only have they all brought the allowed fully loaded carry-on & checked-in luggage weight but exceed the free-limits. They are all ...
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3answers
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Do some airplanes have weighing scales on the landing gear?

It seems to me that takeoff weight is an important piece of data, and if one had weighing scales between the wheels and the aircraft body, one could precisely determine it. However, searching the ...
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1answer
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How does a commercial airliner measure its weight/mass?

Other questions currently being answered cover situations regarding planes near, at or even above their MTOW. It raises a more basic question: how is the exact "ramp weight" of an airliner measured or ...
29
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5answers
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Is passenger weight distribution important on a commercial flight?

This is something I've wondered about for a long time. On really large airplanes, like a 747-400 or A380 for example, I would assume that the weight of the passengers on board is a significant to the ...
28
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7answers
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Can an airline reject a passenger for being overweight?

I have a Cessna 172S and despite having 4 seats in the cabin, I cannot take 3 more passengers besides myself as the pilot with a full tank of fuel due to safety in weight balance issues. As the pilot,...
25
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5answers
11k views

Are passengers really not allowed to change seats before take-off due to weight and balance?

Just boarded an A320 with many open seats (Spirit), and the flight attendant said we may not change seats until at altitude due to weight and balance. Is he just trying to prevent pax from moving ...
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6answers
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Can passenger movement in an airliner make it stall?

This question shows a couple of air hostesses dancing during mid-flight and the co-pilot came out of the cabin to record it. This made me wonder: Can flight crew or passengers moving around in ...
23
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3answers
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Does weight and balance of an airplane matter more on takeoff?

On a few international flights with non-full cabin, the crew has asked no one to move to open seats until the plane has finished take-off. I assumed this was just to force people to sit down during ...
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4answers
2k views

Which aircraft require that the vertical position of the centre of gravity is checked?

We normally check the aircraft CG along the longitudinal axis and the lateral axis (sometimes referred to as the transverse axis) to ensure it is within limits. Until recently I was unaware of any ...
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4answers
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What would happen if a plane lost half of its weight instantly?

During the Second World War the RAF had a 10,000 kg bomb, the "Grand Slam", which was dropped from a Lancaster bomber. I assume that when this was dropped the plane would lurch upwards. Is there any ...
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8answers
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Can passenger distribution cause a parked airliner to tip?

This question on Travel.SE recounts a situation where a passenger, about to disembark from a commercial airline flight, was asked by a flight attendant to wait for other passengers to "catch up". ...
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2answers
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How much does the landing gear compress on a fully loaded airliner on the ground?

When an empty airliner is loaded with passengers, cargo and fuel, the extra weight compresses the gear strut and it sinks. Jet bridges are designed with this in mind. How much height does it actually ...
18
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5answers
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What are different types of weights of an aircraft?

When looking at different aircraft's specifications or in POHs/AFMs, there are several different weights of the aircraft mentioned (e.g. maximum take-off weight, maximum landing weight, operating ...
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2answers
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How much water does the Emirates A380 carry in order to provide onboard showers?

Do you realize that we are living in a world where you can get on an airliner and disembark cleaner than when you got on? Video: Shower in A380 First Class This just blows my mind. How much water ...
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1answer
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Is it legal to overload a plane in Alaska?

Is it true that it's legal to fly a plane over max gross weight in Alaska? If so, what are the rules?
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1answer
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Why is the top left corner cut off on the cg location envelope for small airplanes?

Why does the PA-28 C.G. envelope have the top left corner cut off rather than allowing higher weights at a forward C.G. like it does at the aft C.G.? (source)
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3answers
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Are there advantages when operating with CG near forward or aft limits?

If the center of gravity of an airplane is too far aft, it will become more unstable Iif the CG is too far forward, then drag will increase due to increased angle of attack. But what are the ...
15
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6answers
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What kind of problems can a flight have if passenger weight is miscalculated?

There was a widely reported news story about a TUI Boeing 737 flight, where a bug in reservations system caused 38 passenger on the flight to be allocated a 38kg standard weight as opposed to the ...
15
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3answers
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Do all aircraft carry depleted uranium as counterweights?

I was told that most aircraft had depleted uranium on board as counterweights. I have not seen one myself. Do all current modern aircraft have depleted uranium on board?
15
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4answers
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How is the weight of an airplane measured?

Many very large airplanes have specific information of their empty weight. For instance the weight of an empty, regular 747-400 is 393,263 lb (178,756 kg) according to Wikipedia. The Concorde is 78,...
15
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2answers
6k views

How often does fuel dumping from planes in flight actually occur?

There are a couple of questions about the emergency procedure of fuel dumping, used to reduce the weight of airplanes to be able to land. This is certainly interesting, regarding environmental ...
15
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2answers
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Why is manoeuvring speed higher in utility category?

In a C172P, the manoeuvring speed is 99 KIAS at 2400 lbs, 92 KIAS at 2000 lbs, and 82 KIAS at 1600 lbs. However, it is 102 KIAS at 2100 lbs when in the utility category, which has a more restrictive ...
14
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1answer
886 views

How would a tricycle-geared aircraft be recovered from a tip-up?

If improper loading leads to a tip up on a tricycle-geared aircraft: Image source what methods are used to right level the aircraft? I can imagine inflating airbags under the tail, or lifting it with ...
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4answers
3k views

How does dropping ordnance affect the weight and balance of the aircraft?

During a mission, military aircraft often shed a lot of weight from takeoff to landing. An F-15C (empty weight: 28,000 lbs) carries an internal fuel load of 13,455 lbs (almost a third of take-off ...
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5answers
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What alternative methods are there for controlling a plane when flight control surfaces have failed?

I saw a TV show once about Japan Airlines flight 123, in which the aft pressure bulkhead ruptured, disabling hydraulics and ripping off the vertical stabiliser. So the flight crashed after some time ...
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3answers
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Can a commercial airliner be too heavy to take off?

According to this question's answers, MTOW (or MTOM) is the Maximum Take Off Weight, which is everything up to and including trip fuel. Then there is one step above that, MRW, or Maximum Ramp Weight, ...
12
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2answers
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Why is there a maximum landing weight limit?

I was told that if the aircraft's weight exceeds the maximum landing weight, it could cause a structural damage during landing, but why? My understanding is that with a heavier aircraft, I need fly ...
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3answers
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Why safe take off weight exceeds the safe landing weight?

This looks contra-intuitive: if a plane can take off and fly horizontally, what prevents it from descending and touching down to the runway with the required small vertical speed?
12
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3answers
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What does %MAC mean?

A document said that the optimum CG position is from 13% MAC to 33% MAC. I'd like to know what that means, and what would this look like on an actual plane.
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2answers
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How does new media streaming technology equate to fuel cost increase?

In regards to this article on BBC, which discusses the use of streaming technology to allow passengers to watch films/TV shows etc. on their portable devices, the following statement caught my eye: ...
12
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2answers
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What is the loading diagram for a C-130J?

I'm a student participating in a design project wherein we have to develop a paper design for a payload to be airdropped from a C-130J. Naturally, I'd like to look at the weight and balance of the C-...
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2answers
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Does the MD-80 seat layout affect the balance of the aircraft?

The MD-80 family has a 2-3 seat layout as seen in this image: Does the layout have any influence on the balance of the aircraft and if so what is used to balance out the weight? Image from seatguru....
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2answers
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How are the limits of the center of gravity chart established?

When one views a center of gravity limit chart, in this case a C-182T chart, one notices that the forward C.G. line has two small bends in it, one around 2250# mark and the other around the 2675# mark....
11
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1answer
473 views

How do water bomber pilots deal with the changing forces and mass when scooping water?

How does a pilot flying the scooping maneuver in a CL415 firefighting plane deal with the changing forces from taking on such a large mass of water (nearly 50% of the plane's own mass) as quickly as ...
11
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1answer
1k views

On a larger airplane, how do they manage balance?

I have flown a bunch of times on a Bombardier Dash-8 Q400 on a couple of different airlines, and several times I have flown a shuttle flight that is basically empty. I have been instructed to change ...
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2answers
3k views

How can the Antonov AN 225 only have 2 nose wheels?

I was watching the video of the AN 225 unloading at Perth airport this weekend, and it suddenly occurred to me that there are about a zillion rear wheels on the aircraft, yet only 2 nose wheels? ...
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2answers
15k views

How do airlines handle uncertainty in passenger weight for weight and balance calculations?

When commercial airlines calculate the mass and distribution of passenger load, in the cases where they do not weigh the passengers directly, they use standard weight measures which have been approved ...
10
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1answer
26k views

What is the weight budget of a fully loaded A380?

Wikipedia provides some numbers (typical empty weight, MTOW, max fuel capacity, etc.), but I can't seem to find more detailed figures. For a purpose of this question, let's assume a fully loaded A380 ...
10
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2answers
328 views

Could landing gear weighing scales be used to detect lack of lift?

There have been several crashes due to ice on wings destroying lift. One of the issues with this is that you can't detect that you don't have sufficient lift until you're already in the air, way too ...
10
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3answers
937 views

What is a good spin aircraft for someone that is heavy?

I've been trying to get a spin endorsement for my CFI, but I've been having a problem trying to find an airplane that I can do it in. I'm 280 built like a linebacker. I'm not that "fat" just heavy....
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4answers
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What are the limits to lateral Centre of Gravity imbalances?

I've never seen lateral CG limits prescribed for aircraft (though I have very imited experience in this realm). Presumably, aircraft are designed to keep the center of balance as close as possible to ...
9
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3answers
4k views

Do additional passengers impact on weight and balance of a domestic airliner?

Recently my kids and I were denied access to our flight because we missed the check in window. We were informed that new calculations would have had to have been made by the pilot, despite not having ...
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3answers
4k views

Don't all airspeeds change with weight?

Ok, so I'm a student pilot, and I'm going over the Vx, Vy, Vne, ... etc., and I see that "maneuvering speed" (the speed at which you can safely apply full flight controls) "changes with weight". ...
9
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3answers
837 views

Does cargo balance affect fuel efficiency in commercial aviation?

Positioning cargo such that the center of gravity of the plane is within a certain range is essential, but is there any advantage to having the center of gravity closer to some ideal point within the ...
9
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1answer
3k views

What are the different structural weight limitations that have to be considered when loading large aircraft?

What are the different structural weight limitations that have to be considered when loading large aircraft? Is there a difference in complexity as to whether it's a passenger aircraft or a freighter ...
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1answer
3k views

Do airlines weigh passengers and baggage before loading the aircraft?

I'm aware of some aircraft that have systems to calculate weight and balance. For those aircraft that don't have such systems, how does the pilot know they are within weight and balance limits?
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1answer
1k views

Why would a plane perform 360° turns to balance fuel on the ground?

Why would a plane need to do a couple of 360’ turns on the taxi way/run-up area. The crew were given clearance to taxi and hold. They told the tower they needed to turn the plane 360’ and were cleared....
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2answers
1k views

How do engineers make sure UAV don't land on their front propeller?

Take, for instance, the following UAV: and suppose you have a payload with a very big volume that fits exactly in the fuselage (and there is no more space), but is extremely light. Thus, the heaviest ...
8
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2answers
35k views

How to do Weight & Balance for Cessna 172?

What is the best method to do Weight & Balance for a Cessna 172? (If it's possible with a small tutorial!) Thanks