Commercial planes with a passenger capacity of 20 or more are equipped with a smoke detector system that monitors the lavatories for smoke. Smoke indicators provide a warning light in the cockpit or an audible/visual warning at the lavatory and at flight attendant stations that would be readily detected by a flight attendant. Each lavatory must have a built-in fire extinguisher that discharges automatically.
Smoking on the plane
Anyone who has ever been on a plane knows (or soon learns) that smoking on commercial aircraft is prohibited by federal law. The ban, which has been expanded over the years to include all devices that produce smoke or vapor (so think all types of cigarettes, cigars, pipes, vapes, and e-cigs), has been in effect on all flights arriving in or departing from the United States since September, 2000.
FUN FACT! The last 2 countries to ban cigarette smoking on planes were Cuba (2014) and China (2017).
Ignoring the law and smoking anyway is a federal offense because of the fire risk it poses in an aircraft cabin. Pilots can send messages to Air Traffic Control such as:
ECAM LAV SMOKE. F/A CONFIRMED PAX VAPING IN AFT LAV. ECAM CLEARED WHEN VAPER STOPPED. DECLARING LEVEL 1 SCTY THRT. RQST LEO MEET US AT GATE. PLANNING NORMAL APPRCH INTO BOS UNLESS U RECOMMEND OTHERWISE.
And…
PASSENGER SET AFT LAV SMOKE DET OFF DUE TO VAPING. WILL NEED RED COAT AND SECURITY TEAM ON ARRIVAL
Those who violate the law can expect to receive a fine ranging from $2,000 to $4,000. An airline also has the right to ban a passenger for life if they’ve been caught smoking on the plane. Jail time may not be a definite thing, but it can also be a possibility. I mean, it IS a federal law.
About that smoke detector
Here’s an example of a lavatory smoke detector (in this case, for an Airbus A320) in action:
“Tampering with, disabling, or destroying smoke detectors in the lavatories is prohibited by federal law.”
OK yeah, but what happens if you do?
Interfering in any way with a smoke detector is considered to be a more severe offense than just smoking in the lavatory. Federal law views it as a direct threat to the safety of everyone on board, so the penalties reflect this.

2 examples of required placard. Both are several years old; the penalty is now much higher
A placard is legally required to be visible in every aircraft lavatory stating that federal law provides for a penalty for tampering with the smoke detector. However, this act is often treated as interference with a flight crew, which carries a maximum civil penalty of several thousand dollars (anecdotally I’ve read it’s up to $37,000 but haven’t found a reference of same). It also increases the likelihood of criminal prosecution.
A friend of mine is a flight attendant for a large U.S. airline. This is what they say FAs on their airline do on their end (they added it’s the same for other U.S. airlines, as well), once they’ve discovered someone has done something to a smoke detector:
- Determine exactly who the passenger is.
- Have a conversation with the passenger about their actions.
- Give them a “notice of violation” card (pretty much explains that they will be met by law enforcement and/or airline representatives upon landing).
- Inform the Captain of all of this, and they report to the tower, ground, and any other departments needed.
- Fill out a report just for documentation purposes.
- Anything past that is in the hands of whatever department the airline deems necessary to handle it.
Because tampering with a smoke detector is a deliberate act that compromises a safety system, it’s always pursued by federal authorities. The consequences go far beyond the fines for smoking alone and often involve a criminal record and potential jail time.
If smoking is so verboten, why do commercial planes still have ashtrays?
Good question. Here’s the answer.
What about private planes?
Another good question. All the rules we’ve mentioned are specifically for commercial airplanes. The rules for private jets depend on the company or owner. Some do allow smoking, some – particularly when you’re talking about a plane that can be rented – do not. Check with the company/owner.
*** Many thanks to my friend, the FA, who — for obvious reasons — wishes to remain anonymous.
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