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Commercial Airplane Operators
Commercial Airplane Op  
QUESTION: Dear Prof Steve

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 ?

Awaiting your reply,

Thanks & Regards,
Prashant S Akerkar

ANSWER: Hello Prashant,

1. The maximum cargo (including passengers and fuels) is fixed individually for each model. The total allowed may be adjusted as a function of conditions such as temperature and elevation of the airport.

2. The maximum cargo (including passengers and fuels) is fixed individually for each model. The cargo weight is not determined by instrumentation on the plane. It's determined by monitoring the  number of passengers and bags and estimating the weight. Significant additional weights such as fuel and commercial cargo are measured and added to the above estimate. Since there is potential error in the estimates that contribute to the  total, the maximum allowed includes a margin. The flight control system of some planes may require that the total weight be entered as data.

3. Yes indeed.

I hope this helps,
Steve

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

QUESTION: Dear Prof Steve

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).

Awaiting your reply,

Thanks & Regards,
Prashant S Akerkar

Answer
Hello Prashant,

Yes to all from top down to the one about an alarm buzzing. I expect there are various ways to announce problems: flashing lights, disabling features etc. Whatever is appropriate would be my recommendation.

I expect the most common time for problems due to overloading would be immediately after liftoff. Another possible time would be if a storm is encountered during flight. Landing would be the least likely time since some fuel would have been burned off by then.

I hope this helps,
Steve

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Steve Johnson

Expertise

I would be delighted to help with questions up through the first year of college Physics. Particularly Electricity, Electronics and Newtonian Mechanics (motion, acceleration etc.). I decline questions on relativity and Atomic Physics. I also could discuss the Space Shuttle and space flight in general.

Experience

I have a BS in Physics and an MS in Electrical Engineering. I am retired now. My professional career was in Electrical Engineering with considerable time spent working with accelerometers, gyroscopes and flight dynamics (Physics related topics) while working on the Space Shuttle. I gave formal classroom lessons to technical co-workers periodically over a several year period.

Education/Credentials
BS Physics, North Dakota State University
MS Electrical Engineering, North Dakota State University

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