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all-time classic:

Would the load shift of all passengers herding at the back, front or one side make the plane hard or even impossible to keep in the air ?

Are there any passenger aircraft where this could be a problem ?


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scope: Q2507 is about unspecified movement of some passengers ("passengers moving around"). This would hardly be a problem. The scenario presented in this question here is an entirely different one, viz a hypothetical extreme case where ALL passengers gather in 1 spot at the front or back. Also, it addresses a very famous airline myth, and as such it has a valuable purpose.

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  • $\begingroup$ This will be a problem on almost every passenger aircraft, or any passenger vehicle in general (air, water, ground, underwater, orbital, etc). $\endgroup$ – user3528438 Dec 13 '18 at 21:35
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    $\begingroup$ Yes, the question is useful. But it's already been answered. There's no point answering it again, because that just fragments the answers and makes them harder to find. $\endgroup$ – David Richerby Dec 14 '18 at 23:05
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The issue at hand is known as weight and balance. Most of the larger airliners do not have much of a problem with a large shift in Passenger weight but shifting cargo has indeed caused accidents (See https://en.wikipedia.org/wiki/National_Airlines_Flight_102) which was what happened when a large amount of cargo, not properly secured, fell towards the back of the aircraft during takeoff causing the B747 to crash.

In general, the smaller the aircraft, the more sensitive it is to Moment and Arm changes in its weight and balance. If there is too much weight towards the rear (known as Aft-CG) then the pilot may not have enough down-elevator authority to keep the aircraft from pitching up even further.

A forward-CG problem may also happen where there is too much weight towards the front of the aircraft which may cause the pilot to run out of UP elevator authority during the landing flare, causing a nose-first landing.

Both fore and aft Center-of-gravity issues have caused airline crashes in the past although usually not from passengers but rather shifting cargo not properly secured.

I am not aware of any sideways loading issues that could not be corrected with aileron (assuming both wings are attached). Flying with more fuel in one wing than the other can be tiresome but is usually safe.

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  • $\begingroup$ So what's the answer to "Would the load shift of all passengers herding at the back or front make the plane hard or even impossible to keep in the air ?" (omitting "one 1 side" since you answered that) $\endgroup$ – summerrain Dec 13 '18 at 22:41
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    $\begingroup$ Individual passengers moving on a large aircraft is obviously not a problem since there will still be roughly as many in front and back on average, but I'd think that 100+ passengers all moving forward or aft in unison could have as significant an effect as cargo shifting. Flight attendants move passengers around (often concentrating them over the wings) on empty flights, so it must matter, but is it dangerous or just annoying? $\endgroup$ – StephenS Dec 13 '18 at 23:10

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