Check the carotid pulse for 5-10 seconds. If you feel no pulse within 10 seconds, start CPR cycles of 30 chest compressions then 2 breaths. Compress the center of the chest hard and fast (atleast 2 acheiving at least 100 compressions per minute) Allow for full chest recoil after each compression.
Carriers are required to provide adequate food and potable drinking water for passengers within two hours of the aircraft being delayed on the tarmac and to maintain operable lavatories and, if necessary, provide medical attention.
One incident in particular got a lot of media attention: in August 2009, 47 passengers spent almost six hours -- longer than it takes to fly across the U.S. -- sitting onboard a plane that was parked on the tarmac of Rochester International Airport in Minnesota.