Here is the scenario: Family visiting and I want to take my brother-in-law (weighs 220 lbs) and his son (weighs 180 lbs at age 16) and myself (I weigh 180 lbs) on a local scenic flight.
I do the weight and balance for my rental aircraft and discover I can not take one of the passengers due to exceeding the gross weight. My brother-in-law opts to stay behind and I take his son. My brother-in-law went about 12 years ago with me when he was somewhat thinner and so was I.
I continue to be bothered by the fact that we all could not go. Here is the specific information for the aircraft and If someone could look at the numbers I would appreciate feedback on whether I figured this all correct. It was based on a 1974 Skyhawk with the following:
Basic Empty Weight of 1431.05 with an arm of 39.67 (moment of 56565.45 or 56.84) NOTE: The weight and balance data for the aircraft states: New Empty Weight Center of Gravity is 39.72 inches ( Is this now the ARM?)
Front Passengers weight of 400 at arm of 37=14800.00 moment (14.8)
Rear Passenger weight of 180 at arm of 73= 13140 moment (13.1)
Fuel weight of 288 (48 gals) at arm of 48.6= 14000 moment (14.0)
A stated moment of -.2 for the 15 lbs of oil.
All weights added equals: 2314.05 (Gross allowed weight is 2300)
CG derived is: 98.54
CG envelope show at max weight of 2300 lbs the range is 88-108. I could not take all 3. Considering fuel burn taxiing prior to takeoff would the 14 pounds be acceptable know ing the hour long flight would reduce the weight by roughly 40 pounds?
I know this is a lengthy question but would appreciate help on this. It seems to me that with full fuel it would be almost impossible to take 4 passengers in a C172 unless they were all very thin! I also might add that the FBO I rented the aircraft from could not tell me if the aircraft had the 48 useable capacity tanks or the 38 useable tanks. This is another issue I will address with them because no literature on the aircraft specifcally told me the tank size so I had to consider the higher weight. With the standard tanks of 38 usable gallons the weight would have been fine however it still seems the 400 lbs would have to be in the rear seats.