The tarmac delay rule is the US Department of Transportation regulation (14 CFR §259) that caps how long an airline can keep passengers on board a taxied aircraft (3 hours for domestic, 4 hours for international flights) before it must return to the gate.
The rule applies to US carriers and to foreign carriers operating to and from US airports. Beyond the time caps, the airline must provide water and snacks within 2 hours of the tarmac delay starting, and working lavatories throughout. Serious violations carry per-passenger civil penalties. Support agents rarely process a tarmac-delay claim directly (there is no fixed cash payout to the passenger under the rule), but they field the complaints and inform passengers of their right to file with the DOT. Verify against primary source at build time.
Beware confusion with EU261: there is no tarmac-delay-specific compensation to the passenger under the US rule; the fines go to the government. What the passenger gets is refunds (if the delay converts to a cancellation), duty of care during the wait, and a filing right with DOT.
Common questions
How much does the DOT fine an airline for a tarmac-delay violation?
Up to USD 27,500 per passenger for the most serious violations. Actual fines vary case by case. Verify against primary source at build time.
Does the tarmac delay rule pay compensation to passengers?
No; the fines flow to the DOT, not the passenger. Passenger relief comes from refunds, duty of care, and any voluntary carrier gesture.