while Ouimet was out of the cockpit, Benetti again told Cameron that he thought the smoke was clearing. The captain, still believing the fire was in the lavatory trash bin, had not started descending because he expected the fire would be put out. Shortly after, the "master caution" light in the cockpit illuminated, indicating a loss of main bus electrical power. The captain called the air traffic controller (ATC) in Indianapolis, Indiana, and notified them that Flight 797 had an "electrical problem." Flight 797's transponder signal then disappeared from ATC radar displays; ATC was able to monitor the flight by switching to primary radar tracking. At 19:07, Ouimet reached the aft lavatory again. He reached to open the door, but because it felt hot to the touch, he decided not to open it. Ouimet directed the flight attendants to keep the lavatory door closed, then returned to the cockpit, where he told Cameron, "I don't like what's happening, I think we better go down, okay?" Cameron detected urgency in Ouimet's voice, which he took to mean an immediate descent was needed. Just after Ouimet returned to the cockpit, the cockpit "master warning" light lit up, warning the pilots of a loss of emergency electrical power. Cameron ordered Ouimet to switch to battery power, but the loss of main and emergency electrical power caused some electrical systems to fail, including power for the horizontal stabilizer. This caused the stabilizer to be stuck in the cruising position. This made controlling the plane's descent extremely difficult and required great physical exertion from the pilot and first officer. In addition, both flight recorders stopped recording at this point. Descent At 19:08, Captain Cameron began an emergency descent and declared "mayday, mayday, mayday" to Indianapolis ATC. Controllers granted Flight 797 clearance to descend for an emergency landing at Cincinnati/Northern Kentucky International Airport in Boone County, Kentucky, near Cincinnati, Ohio. Because the loss of electrical power had impaired some flight instruments, controllers had to direct Flight 797 to the airport using a "no gyro" approach, with the controller observing Flight 797 on radar and directing the flight to make turns based on radar position and heading. Smoke filled the passenger cabin and entered the cockpit as the plane descended. The PA system also failed, leaving the flight attendants unable to communicate efficiently with the passengers. Nevertheless, attendants were able to move all passengers forward of row