When a plane is on an active taxiway you need to stay in your seat, otherwise the captain usually won’t move the aircraft. But if you’re in the air, it’s another story.
As I explained nearly three years ago generally flight attendants don’t actually care if you use the lavatory while the seat belt sign is on. They have to tell you that the seat belt sign is on. They cannot tell you it is ok for you to use the lavatory.
I watch passengers, over and over, asking permission. The flight attendant cannot give you permission. Because what if something bad happened? That’s on them and the airline. But if they advise you that the seat belt sign is on and you go anyway it’s pretty much on you.
Now, of course, you must follow flight attendant instructions. So if they actually do tell you to sit down, you’d best do it. Most of the time passengers think a flight attendant is telling them to sit down when they’re just saying the seat belt sign is on. Occasionally I see flight attendants saying ‘the seat belt sign is on’ while making faces and motioning passengers into the lav.
If you can wait until the seat belt sign is off, that’s better. But if you can’t, and sometimes you just have to go, go. Try to avoid doing so right after takeoff, right before landing (first and last 5 minutes!).
And don’t assume a flight attendant is saying ‘no’ and jumping to offense, arguing, or threatening. That never ends well.
Instead just say, “yes, I understand, and unless you specifically tell me that I cannot use the lavatory I am going to go because it’s an emergency.” Then go, unless you hear instructions to the contrary.
That’s the practical real world answer. What about the law? Finally we have that answer too.
- It is a violation of 14 C.F.R. 121.317(f) not to have your seat belt fastened when the seat belt sign is on. Civil penalties up to $10,000 could be assessed. However there has been no enforcement action taken against a passenger solely for violating this rule in the last 5 years.
- Failure to comply with crewmember instructions violates 14 C.F.R. 121.317(k).
An illustrative case is Wallaesa v. Federal Aviation Administration, 824 F.3d 1071 (D.C. Cir. 2016).
A male passenger became infatuated with a female passenger and began to harass her. Flight attendants moved him away from her, but he continued to seek her out, ignoring the “fasten seat belt” sign and the repeated instructions of the flight attendants.
An FBI agent who happened to be on the flight eventually intervened and restrained the passenger.
The FAA imposed a civil penalty, initially citing both the seatbelt rules and the rules requiring compliance with flight attendants’ instructions.
In litigation over the penalty, the FAA expressly took the position that while the passenger had violated the seatbelt rule, that violation “did not merit a penalty.” The agency contended that the passenger’s noncompliance with the flight attendants’ instructions did merit a financial consequence, and the various tribunals to consider the matter agreed.
So there you have it. As long as you don’t disobey a crewmember instruction in the process, you’re on pretty safe ground using the lavatory when the seat belt sign is on.
Most of the time a flight attendant will tell you the seat belt sign is on, which is not the same thing as telling you that you cannot go to the bathroom.