Being in transportation-related media and therefore perpetually online, I often see videos of airplane passengers acting “unruly.” In other words, someone films another occupant having a really, really, bad day. After watching so many recorded incidences, I’ve wondered whether there are formal rules other passengers should consider when faced with a violent fellow traveler. No doubt that most scenes benefit from a lack of your direct involvement. However, if someone’s endangering others, when should non-crew step in?

The FAA has a “zero-tolerance” policy on unruly passenger behavior

Since occupant, crew, and cockpit safety are critical mid-air, anyone a flight attendant or the crew deems unruly is met with severe consequences. The FAA will fine up to $37,000 per violation and then press criminal charges.

Still, not knowing exactly who’s supposed to handle violently unruly passengers can make boarding any old flight an unknown. Air marshalls aren’t on every flight. After all, the FAA oversees more than 45,000 flights every day. While the FAA can deploy air marshalls where actively needed, you might as well just expect your domestic flight not to have one.

The general rule of thumb is to let the flight attendant handle things

Mid-air, there’s usually nothing worse for diffusion than having “too many cooks in the kitchen.” Most often, allowing the flight attendant to work their trained protocol is best. This usually involves quietly communicating with the unruly or upset passenger and deciding how to classify the scene (pre-emergency, emergency, etc.).

Ask first to avoid any legal or safety ramifications

Still, some passengers board under the influence or are in a low mental state and at some point decide to act out violently. In these cases, while the flight attendant has training to handle them, things can get out of hand. You might simply ask if they need help.

If you don’t ask and get an affirmative response, you could be putting yourself at both legal or personal safety risk.

It seems some experts do recommend helping a flight attendant with an unruly passenger in extremely rare cases

WingTalkers says “If cabin crew have failed or are failing in all efforts to resolve the situation. And they need to physically intervene to control the passenger, then it is common for them to enlist the support of travelling law enforcement personnel or other able-bodied passengers.”

So, the crew might ask for help, or you might offer and get a positive response. In these very rare cases, passengers might actually save the flight from a critical emergency state.

In November, an American Airlines flight attendant signaled for help behind her back

On a flight from Milwaukee to DFW, American Airlines flight 1915 passengers worked together to take down a Canadian man who attempted to open the plane’s door mid-flight.

According to one passenger involved, the flight attendant attempted to diffuse the angry passenger before he demanded an exit. The flight attendant signaled for help behind her back. The man struck the attendant on his way to the door.

Passengers ended up taping the man’s hands and feet and holding him down for the last 30 minutes of the flight.

Before getting involved in any unruly passenger scene, do a careful risk assessment and consider your own safety and the safety of those around you. Read any signals coming from the flight attendant. While the signs might not be altogether clear, an emergency involving groups of people often requires situational awareness and lacks a standard rulebook. As shown above, passenger involvement can mean the difference between having the plane’s door ripped open 30,000 feet up or a safe emergency landing. Of course, the hope is that you’ll never need to do anything other than attempt to enjoy your flight.