# 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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### 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 ...
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### What is the location of the CG on the T-38?

Is the Northrop T-38 Talon's CG forward or aft of the center of lift (like the F-16)?
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### Passenger cabin asymmetric seating and balance [duplicate]

In the early 1990s I made many short haul flights in Short 360 aircraft. These had passenger seats set up as two rows on the right, one row on the left as per the picture. Assuming a full load of ...
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### What is the meaning of Minimum Flight Weight?

In the Aircraft Flight Manual of the Bombardier CRJ700, the Minimum Flight Weight is listed as 42,000lbs. What is the meaning of Minimum Flight Weight?
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### How to calculate and check if a/c can carry additional reserve fuel without affecting payload and if so how much?

Find payload and state if a/c can carry additional reserve fuel without affecting payload and if so how much? Max take off weight= 45000 lbs. Max landing weight= 40000 lbs. Flight fuel= 4000 lbs. ...
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### Why is the CG assumed to be between the CP and the tail?

While discussing stability (Longitudinal, Lateral, Directional), invariably, all texts assume CG to be between CP and tail. Ex: Look at the specific image in wikipedia https://en.wikipedia.org/wiki/...
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### Do aircraft usually fly with CG at 50 percent of chord or do I need to reduce the tail volume?

I'm working on a design having a 3.2-metre wing with a constant chord section in the middle and taper on the sides. With a tail volume of about 0.68, the neutral point is at 60% chord from the leading ...
181 views

### How does a small charter operator determine where the centre of gravity is for a given flight?

I was reading an account of the 2001 crash of a charter aircraft carrying the singer Aaliyah and her companions. Within it there's a summary of the investigation by the NTSB which includes the text '...
59 views

### What are the regulatory requirements requiring Weight and Balance be onboard aircraft for flight? [duplicate]

The common mnemonic ARROW teaches private pilots a Weight and Balance must be onboard the aircraft for flight (usually included in the POH/AFM). What is the regulatory requirement for this? In my ...
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### How do VTOL aircraft like the V-22 Osprey not tilt?

How do aircraft like the V-22 not tilt under an unbalanced load? if they are only supported by 2 forces on either side a large weight in the back should cause it to lean backward when stationary, ...
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### 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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### 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 ...
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### Do you have to update weight and balance charts after installing new avionics?

The POH always has weight and balance charts. Let's say you install some new avionics, hence changing the weight of the aircraft. Do you need to update the POH binder with new weight & balance ...
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### What are the empty weight and maximum takeoff weight of the Moller Skycar?

I know what are empty weight and MTOW, which are data I need for my school project. But the website for Moller Skycar only shows the gross weight and net payload: https://www.moller.com/...
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### How is the Max Zero Fuel Weight used in calculating weight and balance?

In some weight and balance apps there is an option to "Use Max Zero Fuel Weight". Having never seen this in any of the aircraft I have experience flying, I am curious how this value is typically used ...
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### How is fuel removed from a light aircraft if required for weight and balance?

With small, light aircraft, weight is always a consideration. Say you had a four-place single engine aircraft that you wanted to take yourself and three of your (non-FAA-standard weight) friends, but ...
3k views

### How are forward and aft CG limits calculated?

I have been tasked to create a POH for my aero engineering coursework and part of this task is to create the CG envelope for the theoretical 65 passenger aircraft. I have figured out weight, moment ...
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### Why is the CG envelope wider when the aircraft is heavy?

I mean, the same aircraft, but empty or on MTOW. According to MAC, those limits are the same, but the indexes are different. So if I understand that correctly, the CG can be more forward when the ...
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### In a hydrogen fueled plane, could part of the fuel load be allowed to become lighter than air to offset or trim for the load?

This is inspired by How can adverse maneuverability due to a fuel tank behind the rear pressure bulkhead be mitigated in Airbus ZeroE hydrogen plane? . I was thinking, with the cryogenically stored ...
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### How can adverse maneuverability due to a fuel tank behind the rear pressure bulkhead be mitigated in Airbus ZeroE hydrogen plane?

Airbus recently announced three concept aircraft for commercial use, powered by liquid hydrogen, with an ambition to have the plane in operation by 2035. https://www.airbus.com/innovation/zero-...
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### What does the ACARS Weight and Balance Request page look like?

In the ATSU AOC Preflight menu of an Airbus (maybe Boeing too), there is an option for a weight and balance request. The selection name varies by airline but it may say "W/B Req" "Send ...
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### For CG calculations, where is the root chord located on a swept wing aircraft?

With a swept wing aircraft (specifically a MiG-25 I am modelling) where is the root chord taken from to calculate the location of CG? Is it the root chord of the wing (where it attaches to the ...
650 views

### Why is a weight and balance graph lozenge-shaped?

(fireair.co.uk) Why is a weight and balance graph lozenge-shaped? I have tried to find the answer but it seems to be really hard to find. Why is it not a square?
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### What is Full Fuel load and how does it differ from Fuel Capacity?

I've noticed that the fuel capacity is much higher than the full fuel load. For example in a Cessna citation 560XL The Fuel Capacity is 6740 lbs The Payload W/Full Fuel load is 960 lbs Why is there ...
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### How do handling characteristics depend on flying with a full vs. an empty tank?

Modern aircraft are capable of carrying a lot of fuel to achieve extra-long range; we're at a point where nearly every pair of destinations can be reached non-stop. Carrying so much fuel imposes ...
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### Why should the centre of mass be ahead of the centre of pressure?

Why is the centre of mass located ahead of the centre of pressure? And what would happen if centre of mass would be too close or too far away from the centre of pressure?
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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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### Are there regulations about carrying cargo on passenger seats?

We see that passenger aircraft have recently made cargo flights so that the supply chain does not decrease due to the Covid-19 crisis. It is seen that the cargo boxes are loaded on the passenger ...
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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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It is well established (How Centre of Gravity (CG) is adjusted? and elsewhere) that adjustments can and need to be made to insure that airplane loading maintains a suitable center-of-gravity for the ...
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### Should the weight of the lifting surfaces be deducted from the weight used to calculate the C of G of the aircraft?

If the aerofoils are creating lift they are doing the work to lift the helicopter. When the helicopter is hovering, the blades are carrying the weight of the entire ship. The forces on the aerofoils ...
362 views

### How to adjust the center of gravity of an aircraft if not level when being weighed?

how do you adjust the center of gravity when weighing an aircraft in not-leveled position using platform scales under the nose and the main gears, and dropping a plumb bob to mark the gears locations.
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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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### 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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### Do negligible weights affect the control of a commercial aircraft? [duplicate]

I was watching a video and it said that switching seats on a commercial airplane would be fatal. "Switching of seats from the rear of the airplane to the front seats would result in probable accident"....
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### When does a Maximum Taxi Weight Restriction happen on a 737-800?

This is the first time I experienced restriction in taxi weight on B737-800. Have you experienced that before? All I know that restrictions will be from MZFW/MTOW/MLW. When does it happen?
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### Is moving payload masses during flight to restore mass centering, or to avoid having to trim, a useful approach?

Note: Title was previously "Movable big missiles/bombs/tanks under fighter jets: conceivable?" Example: lateral weight distribution in fighters Fighter-bombers jets are small and lightweight in ...
263 views

### Can i create a home built aircraft with this engine?

http://www.chiefaircraft.com/da-100.html Would this engine work for a homebuilt ultralight aircraft? I am still in the research phase, so i don't know what the weight of the aircraft will be, but I ...
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### 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....
210 views

### Do airline dispatchers pre-block seats for weight and balance on large wide body aircraft?

I was reading a Oman Air flight review and one of the bits intrigued me: I had earlier used ExpertFlyer to monitor both how busy the flight would be and the seat map. I selected a window seat ...
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### What is aerodynamic imbalance?

What is aerodynamic imbalance on a propeller? The most amount of hint I got was the shape of the airfoil. All I know is that it is the different thrust each prop blade produces due to different angles ...
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### Is there a method for calculating change in V-speeds with a change in weight for a Cessna 172?

For example, what would the rotation speed (Vr) and stall speed (Vs) be at maximum takeoff weight versus flying with a single occupant? (2297 lb vs 1807 lb)
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### How is a misdeclared weight of a mail bag handled? [closed]

What is the proper process when a postal administration tenders a mail bag with under declared weight? Is the bag returned to the postal administration or is the bag weight altered to match the ...
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### Why don't airports have weigh stations to prevent overweight takeoffs?

Currently, ensuring that an airplane isn't overweight when it takes off relies on the cargo handlers loading the aircraft properly and accurately documenting (on the weight-and-balance sheet) what ...
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### What are the financial implications for Lufthansa (and other airlines) of keeping the back row of their A320neo free of passengers?

After the recent EASA airworthiness directive concerning the potential for weight and balance problems with the A320neo, Lufthansa announced it would no longer sell seats on the back row of those ...
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### What if all passengers move from one side to the other?

Given the question What happens when all passengers jump at once?, I wonder what would happen if they all moved from side to side. If all the passengers moved from the front to the tail, or the other ...
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### Under which condition is a forward CG most critical?

This question is from CFI written exam. (6824) “Under which condition is a forward CG most critical?” The answer is “Forward CG is most critical during landing. If it is too far forward, the ...
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### How much time does it take to calculate the leveling and weighing of big and small aircraft?

What methods are used to achieve that? According to my search : For old planes they use a plumb bob and measuring tools. On new and big planes, the process is computerized. Built-In Electronic ...