# Tag Info

### Why do pilots have to calculate their center of gravity? Couldn't this simply be measured?

It would be possible to design a system that computes an airplane's weight and C of G from the landing gear load in real time, either by incorporating load cells into the gear legs, or measuring ...
• 132k

### Why do pilots have to calculate their center of gravity? Couldn't this simply be measured?

It's not only possible, it's been done on military transports and some cargo aircraft. However, one still needs to know the aircraft's mass (not weight) prior to takeoff. Gear-mounted strain sensors ...
• 27.6k

### Why do pilots have to calculate their center of gravity? Couldn't this simply be measured?

If I'm right about this being Midwest 5481 the incorrect calculation of Centre of Gravity was not the full cause of the accident. Most, of not all, accidents are caused by a series of events - what is ...
• 33.7k

### Why do pilots have to calculate their center of gravity? Couldn't this simply be measured?

Because it would be expensive and just add something else to the list of things to maintain. It's easier to calculate the empty weight CG and then add to that anything else you load on the a/c. Such ...
• 13k

### Why do pilots have to calculate their center of gravity? Couldn't this simply be measured?

The short answer for cargo aircraft is because you always calculate the CG before you ever load the airplane. You then load to achieve the calculated CG. It's a proactive approach that's simple, ...
• 26.9k
Accepted

### How do I interpret these Center of Gravity limits?

source: own work It means that your centre of gravity needs to be in the hatched area of the diagram. I've assumed an empty weight of 1600lb for the C172. You have to calculate the weight of the ...
• 83.6k
Accepted

### Is there a reason why the vertical lines of some airplane envelope graphs are not parallel?

This kind of presentation is called a weight vs. moment 'fan chart'. Although the labeled and drawn x-axis is in CG position, it is really calculated in terms of moment (inch-lb). The reference ...
• 13.2k

### Why do pilots have to calculate their center of gravity? Couldn't this simply be measured?

Just to complement the other answers a bit: Sensors are normally already installed on the landing gears in order to indicate if weight is loaded on them and determine if the aircraft is on ground. ...
• 13.8k

The most likely reasons you are experiencing this: The shaft is not exactly at the center of the propeller. The length of the propellers is slightly different. The density of the propellers is not ...
• 2,759
Accepted

### Determining Required Fuel from Payload/Range Diagram

The gradient between points A and B of your diagram is determined by the overall efficiency of the airplane. It depends on the amount of fuel needed to fly a bit further by trading payload for fuel ...
• 234k
Accepted

### Does the useful load contain taxi fuel?

Yes, the useful load includes taxi fuel. Both definitions are correct and do not contradict each other: The Useful Load is the total mass of the passengers, baggage and cargo, including any non-...
• 26.9k

### How reliable is the Airbus FAC calculated gross-weight?

This is old FMS. GWFK is AOA/FAC calculated, and used for Vls when landing. The GW in the lower ECAM is based on the figures you put in the FMS (fuel+ZFW). I believe the newer FMS gets Vls based on ...
• 21

### What can happen if everyone congregates at the back of a parked plane?

Loading up the back of a plane can indeed cause it to tip backwards and come to rest on its over-rotation skid. For this reason, some planes actually come with a detachable strut that holds up the ...
• 21.3k
Accepted

### Can passengers boarding back first tip back an airplane?

Not if everything else is normal. Airliners are built with the expectation that they will be boarded to the back first on some airlines. The CG limits for the 737 are approximately 12%-31% MAC, ...
• 27.6k
1 vote

### Why do pilots have to calculate their center of gravity? Couldn't this simply be measured?

When Concorde was being developed a knowledge and control of CofG prior to take off was important to maximizing fuel efficiency and range, as poor loading would require excessive trim and increase in ...
• 11

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