Have you ever wondered what would happen if every single passenger on a plane got up at the same time and started jumping up and down?
No? You haven’t? Well, we have, and luckily for us, Quora user Steve Angel wondered the same thing. He posted his question to the social networking site and in return we all get to enjoy this rather in-depth answer by P. J. Harb, who notes he is an engineer, musician, traveler, linguist, and “aspiring pilot.”
“To answer your question, let’s say each one of the 300 passengers weighs 75 kilograms,” Harb began. For the Americans in the crowd, that’s about 165 pounds. “75 KGs x 300 passengers = total weight of 22,500 KGs/22.5 tonnes. If they all jumped at the exact same time, let’s imagine there is a sudden force equal to a mass of 22.5 tonnes.” That 22.5 tonnes equates to 45,000 pounds.
The average Boeing 777 aircraft, Harb said, weighs around 300,000 pounds (without passengers, bags, or fuel). With payload at take-off, that number will be closer to 400,000 to 500,000 pounds, or 200-250 tonnes.
“These 250 tonnes will be moving at around 500 miles per hour mid-flight. Because of the aircraft’s weight and speed, even if there was a 22.5-tonne sudden/brief downward force within, its flight would be mostly unfazed,” Harb explained. “Its altitude (height) may decrease slightly but only for a brief moment, because its autopilot system will immediately correct it. The pilot will feel some vibrations.”
In a twist, Harb explained that there are much stronger forces already exerted on an aircraft’s fuselage (body) during severe weather conditions.
“The autopilot system is constantly monitoring the aircraft’s altitude and speed, and adjusts engine power based on these. For example in bad weather, a microburst (sudden downward burst of wind) exerts a super strong force on the aircraft, and the autopilot system works to correct it immediately, by increasing engine power and pitching the aircraft up.”
To sum it up, Harb said, the force exerted by the 300 unruly passengers would do little to the aircraft, so we can all rest assured that if our flight breaks out into a dance party we will still make it to our destination safely.
For the record, this isn’t the first time a very important aviation question has been answered on Quora. In 2017, a flight attendant also gave a very detailed answer when asked about how to survive a plane crash, while another attendant shared the best breakfast options on varying flights.