ELI5: Why do plane and helicopter pilots have to pysically fight with their control stick when flying and something goes wrong?

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As others have said, that’s largely theatrics in movies and TV. There are essentially three systems in use: * Fly-by-wire is what you will predominantly see in modern airliners and military aircraft. Here, your stick isn’t actually physically linked to any control surface – instead, your inputs send signals to a computer which then positions flight control surfaces to do what you are asking the computer to do. The computers are, in relaxed stability aircraft (like fighter jets), actually continuously sending signals to the flight controls to keep the jet flying stable. In some aircraft, if you turn off the flight control computers entirely, your jet is no longer able to maintain controlled flight. In this case, the fighting control stick does absolutely nothing. In fact, you won’t even feel the actual feedback from flight control surfaces on aircraft because the stick isn’t directly linked to them. * Hydromechanical. This is used in older fighter jets and in airliners/aircraft with big control surfaces. Basically, when flying at faster speeds (which creates larger pressure/air loads on control surfaces), human power isn’t enough so the control stick is *mechanically* linked to hydraulic systems that move the control surfaces for you. These hydraulic circuits operate in the thousands of psi. For instance, if you pull the stick back, you are mechanically telling the servos and actuators to move the stabilator (or elevators) to pitch the aircraft up. In this case, if you did have something go wrong, fighting the stick doesn’t do much either. Most likely, if something went wrong, it’s because your hydraulic line or mechanical linkage broke, or you lost a control surface. In which case, fighting the controls won’t do you anything. * Direct linkage. This is what you commonly see in older aircraft/lighter aircraft/general aviation like in your Cessna. Here your control surfaces are directly linked to your control stick/rudder via wires and pulleys. You will directly feel the loads on the control surfaces. Here is where you could, like in the movies, perhaps try to fight for control via physically fighting the stick more. A jammed linkage or connection might require more force to fight through. But even then, you risk breaking something even worse (sudden snapping of control surfaces can overwhelm mechanical limits) OR getting into a PIO (pilot induced oscillation). MORE likely to happen is if you have a failure in a control surface (e.g. an aileron fails), you have to put in some input like rudder or opposite aileron to keep the plane flying straight and level. In that case, you are “fighting the controls” by keeping some force on the stick to maintain the flight attitude you want. But you aren’t “fighting the stick” like in the movies – instead, you’re precisely and finely putting your control inputs in (or trimming the aircraft) to offset what was lost.

nice_big_cup_of_stfu

The controls are often (especially in older aircraft designs) physically linked to the control surfaces by steel cables. If the force of air is pushing on the ailerons/elevator/rudder it’s also moving the stick around.

rhomboidus

Helicopter pilot, answer is you don’t unless the hydraulic system has failed. This is less likely the larger the helicopter as they have multiple independent hydraulic systems so one failing has no effect at all. Smaller helicopters like Jetrangers or Astars are harder to control with a hydraulic failure but not even that bad, we train to land with the hydraulics off by flying real aircraft with the hydraulics turned off, it isn’t considered dangerous to do so. For a large helicopter if you somehow had all hydraulics fail at the same time depending on the type it is a major emergency and possibly unrecoverable.

CryOfTheWind

One thing I haven’t seen directly mentioned is World War II era fighters/bombers were all cables and pulley rigging for the control surfaces. If those planes dive at the ground during dogfights or attack runs and get going really fast, the forces to move the controls becomes extreme. Thus, you could get into a dive you couldn’t physically pull out of. So, this can be quite realistic for some movies but for modern aircraft the biggest issue where a pilot is straining against the controls is something like runaway trim/autopilot. For most everything else you’re not fighting with the controls.

tehmightyengineer

Another pilot here. All the controls in my plane are directly connected to the yoke and pedals (manual). When airflow is low, especially during slow flight such as during landings, controls require exaggerated expression. They don’t have much lift being generated to cause a change. Alternatively, very strong winds in lighter aircraft can definitely cause you to fight. They can quickly push you and change your pitch, yaw, and roll (these are the axis of motion). In this case you have to counter the effects of the wind. Most of this is experienced extensively by all pilots in training. But it can take real physical effort (without much return from the controls). Usually however, you fly with “two fingers”. A light touch will do it 9 times out of 10 if you’re trimmed in (tuned controls to stable). Remember, flight is across long distances and you generally navigate on 10° increments (eg 010° – 360°) or smaller so planes must fly on small movements and corrections not grant turns like you see on movies. The only times I’ve ever done movement like that when not training and with passengers was during some landings where the wind goes dead on me or once with an engine out on takeoff with about 400 feet below me to return to runway.

Garret_Pp