Air Canada's flight 797 was operating from Dallas, Texas to Toronto, Ontario on the afternoon of June 2, 1983. On the flight deck was Captain Donald Cameron and First Officer Claude Ouimet. Three flight attendants and 41 passengers were also on board the DC-9 that day. Cruising at FL330 over Lousiville, Kentucky, the pilots heard three snaps in sudden succession. Looking behind Cameron's seat, Ouimet spotted three circuit breakers which had popped out. "Which one is that?", Ouimet asked. "DC bus...the left toilet...the left toilet flushing motor" Cameron replied.

The Captain then attempted to reset the breakers, but they would not stay in. Ouimet asked if they should log it to which Cameron replied "I want to log it, yes. Somebody must have pushed a rag down the toilet or something...jammed it and it's over heated."
797 was then handed off to Indianapolis Centre and after a few minutes, Cameron tried again to reset the breakers, but to no avail. In the back of the cabin, a passenger had drawn to the attention of a flight attendant greyish smoke coming from under the door of the left toilet. The flight attendant attempted to enter the toilet with a fire extinguisher, but the thick smoke was too powerful.

Another flight attendant went forward to the flight deck and said to Cameron "Excuse me Captain, there's a fire in the washroom at the back. They're just going back to put it out." Cameron then instructed Ouimet to go back and take a look at the situation. The third flight attendant had now opened the toilet door and discharged the fire extinguisher. Passengers were now being moved forward away from the smoke. Ouimet was unable to reach the toilet by this time because the smoke had become too thick, but the flight attendant told him that he had seen no flames in the washroom while discharging the extinguisher. Ouimet went back to the flight deck to get a pair of goggles, but the flight attendant came forward, saying the smoke had begun to dissipate. Ouimet got goggles regardless and went back to the rear of the aircraft. Just after he left, the master caution light illuminated on the panel, indicating a loss of the left AC and DC power systems.

In the back, Ouimet found the toilet door hot to the touch and was about to tell the other flight attendant not to open the door when he saw the flight attendant at the front of the aircraft waving him hurriedly back to the flight deck. As he reached the flight deck, he saw that now the emergency AC and DC buses had lost power. The crew activated the emergency battery power and Ouimet said "I don't like what's happening, I think we'd better go down." Cameron then told the flight attendants that they would be making an emergency descent and to prepare the cabin. Ouimet made a mayday call to Indianapolis as Cameron put the aircraft into it's descent. As the descent began, there was a noise from the aft of the aircraft and black smoke began to billow forward. Indianapolis instructed 797 to descend to 5000ft for vectors to Cincinnati. Due to the lose of electrical power, 797's transponder was not functioning so the controllers had no indication of the aircraft on radar.

Smoke had now filled the cabin, passengers being supplied with wet towels to hold over their face, and into the flight deck, the door having been left open.
Both pilots donned their oxygen masks and Cameron put on goggles. Once 797 got closer to Cincinnati, the Approach controller was able to pick up the aircraft's target on radar. Because only emergency power was available, the pilots only had a back-up attitude indicator available to them. 797 was now 21 miles southeast of the airport descending through 8,000ft in solid cloud. The approach controller instructed 797 that it would receive a no gyro approach to runway 27L. 797 descended to 2,500ft and was able to get into clear conditions, though visibility was by no means good in the cockpit. Ouimet periodically opened his sliding window to vent smoke out.

As the controller turned 797 onto final, he turned the runway lights up full. Ouimet exclaimed "OK...we have the airport!" to which approach replied "The tower has you in sight and you are cleared to land." Ouimet yelled back into the cabin for everyone to sit down and a few moments later 797 touched down smoothly. Because the electrical power had been lost, brake antiskid was inoperative and four main tires blew out. After stopping and shutting down, Ouimet immediately exited through his sliding window and assisted the Cameron out from his side. Almost all of the emergency doors were opened immediately and passengers began evacuating. Unfortunately, the smoke was so thick that some passengers could not find their way to the exits before flames engulfed the aircraft. 23 people were killed in the fire.

......Investigation of the toilet flush motor showed that it had not failed prior to the incident nor had it been damaged internally by heat. Tests showed that, even if it had overheated, the magnitude of the heat would not be sufficient to ignite adjacent materials. Analysis of the motor wiring showed that it had been damaged by an already existing fire which caused the circuit breakers to trip. Study of the aircraft showed that the fire had begun behind the toilet's back wall, burning through the walls and allowing smoke to enter the toilet. This was the reason no fire was seen when the flight attendant emptied the fire extinguisher in the toilet.

As the fire burned down below the toilet, the heat was blow onto the generator cables and the circuits opened, taking them offline. The fire then continued to burn in the space between the toilet wall and the aircraft's outer skin, allowing the fire to move forward above the ceiling panels and enter through the ceiling and sidewall panels. Unfortunately, as soon as the aircraft stopped and the doors were opened, fresh oxygen was available to feed the fire and the aircraft was quickly consumed. The precise origin of the fire has never been determined.