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# Aeronautical Engineering/Airplane Load / Weight.

Question

Commercial Airplane Op
QUESTION: Dear Paul

1. Is the Cargo carrying capacity (Load, Weight) fixed or standard in all Commercial Airplane Carriers ?. Is this done for Security measure for not exceeding the total weight, load of the airplane i.e passengers, cargo, fuels, airplane etc ?

2. Is there a certain Total Load or Weight of the Airplane which cannot be exceeded ?. Is this identified by Electronic Instruments panel, Alarms etc indicating the Total Weight, Load of the Airplane to the pilot before flight takes off ?.

3. In case if the Total Load or Weight of a Airplane is exceeded
and still the Pilot tries a take off, can it lead to plane crash ?

Thanks & Regards,
Prashant S Akerkar

ANSWER: Prashant - The cargo capacity of commercial aircraft is determined by the manufacturer and demonstrated to the FAA during certification. The primary motivation is protection of the structure during the various phases of flight. The total allowable weight includes aircraft, fuel, passengers, cargo, etc.

Yes, there is a total weight they are not supposed to exceed. I never heard of an automatic system to measure that. I always thought it was the responsibility of the pilot or flight engineer to know how much fuel, passengers and cargo are coming on board. The ticket desk is supposed to verify that luggage does not exceed allowed limits. The same is true for people loading mail or other cargo.

Exceeding the total weight puts the aircraft in danger. It probably won't crash, but might if it encounters an extreme flight condition such as early hard landing or turbulence gust. And the takeoff roll will be longer than normal which could be bad at some airports.
Paul

---------- FOLLOW-UP ----------

QUESTION: Dear Paul

Thank you.

Can this be considered as a part of Airplane Load / Stress Testing methods ?.

Can we derive some mathematical formula or equation to calculate / compute the Total Weight of the Machine (Airplane) before takeoff ?

Parameters : temperature, maximum power of the engines etc

1 Ton = 1000 kg

Example :

1. Aircraft Weight : x kg - Construction (Manufacturing)
2. Fuels Weight : y kg - Construction (Manufacturing)
3. Passengers Weight : z kg - Load - Includes Crew Cabin - Pilot, CoPilot, Captain etc - Load
4. Cargo Weight : - n kg - Load
5. Miscellaneous Weight - Furniture - Seats, Tables, Utensils - Dishes,Glasses etc) - m kg - Load

Total Weight of the Aircraft W in Tons = x + y + z + n + m.

Should we add safety factor value to this total weight ?

Do you feel electronic instrument panels calculating and showing the Total
Weight (Load) of the aircraft can be useful for Pilot before he takes a take off ?. Alarms will buzz to the Cabin Crew if Overload occurs within the aircraft before the Take Off.

Among different accidents, which are the most likely to occur because of Aircraft Overweight ?

1. During Takeoff.
2. During Landing.
3. During Aircraft flight (i.e. After Plane Takeoff and Before landing).

Thanks & Regards,
Prashant S Akerkar

Prashant - Your equation looks ok, but I don't know how to predict the value of the various parameters.. Weight is usually assumed to be a known quantity and the safety factor is used in the criteria which use weight as an input. If some of the weight is uncertain, you could put a + or - percent uncertainty on the number. That is kind of a safety factor.

Yes, electronic measurement of weight would be useful, but most pilots would still prefer the simple accounting of weights to avoid catastrophic errors caused by the electronic system.

I assume takeoff would be the most likely time for an accident because the fuel load is maximum. After that I am not sure, probably inflight turbulence encounter would be the next most likely. But an early landing would also be very worrisome.
Paul
Questioner's Rating
 Rating(1-10) Knowledgeability = 10 Clarity of Response = 10 Politeness = 10 Comment Dear Paul Thank you. Thanks & Regards, Prashant S Akerkar

Aeronautical Engineering

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#### Paul Soderman

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Aeronautics, Aerodynamics, Fluid Mechanics, Aeroacoustics, Noise Control, Muffler Design, Wind Tunnel Research.... I know nothing about India - do not ask about schools, jobs, application requirements, career choices, etc. for India. Please, no text message verbiage; I prefer full words in full sentences. Thanks.

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38 years as research engineer at NASA

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AIAA, NASA

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B.S. and M.S. Aeronautical Engineering - U. of Washington, Graduate work Standford U.

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AIAA Associate Fellow (American Institute of Aeronautics and Astronautics)