Unfallbericht:Air Canada Flight 797, a McDonnell Douglas DC-9-32, was a scheduled flight from Dallas (DFW) to Montreal, Canada, with an en route stop at Toronto (YYZ).
|Datum:||Donnerstag 2 Juni 1983|
McDonnell Douglas DC-9-32
|Anzahl Zyklen der Zelle:||34987|
|Triebwerk:|| 2 Pratt & Whitney JT8D-7B|
|Besatzung:||Todesopfer: 0 / Insassen: 5|
|Fluggäste:||Todesopfer: 23 / Insassen: 41|
|Gesamt:||Todesopfer: 23 / Insassen: 46 |
|Sachschaden:|| schwer beschädigt|
|Konsequenzen:|| Written off (damaged beyond repair)|
|Unfallort:||Cincinnati/Northern Kentucky Airport, KY (CVG) ( USA)
|Flugphase:|| Während des Fluges (ENR)|
|Flug von:||Dallas/Fort Worth International Airport, TX (DFW/KDFW), USA|
|Flug nach:||Toronto International Airport, ON (YYZ/CYYZ), Kanada|
At 16:25 CDT, Flight 797 left Dallas and climbed to FL330. Except for a deviation to the south of their filed flight plan route to avoid weather, the flight progressed without incident until it entered the Indianapolis Air Route Traffic Control Center's (ARTCC) airspace.
At 18:51:14 EDT, the three circuit breakers associated with the aft lavatory's flush motor and located on a panel on the cockpit wall behind the captain's seat, tripped in rapid succession. After identifying the circuit breakers, the captain immediately made one attempt to reset them; the circuit breakers would not reset. The captain assumed that the flush motor had probably seized and took no further action at this time. About 18:59:58, the captain again unsuccessfully tried to reset the three circuit breakers. He told the first officer that the circuit breaker "Pops as I push it." About 19:00, a passenger seated in the last row asked a flight attendant to identify a strange odor. The flight attendant thought the odor was coming from the aft lavatory. She took a CO2 fire extinguisher from the cabin wall and opened the lavatory door a few inches. She saw that a light gray smoke had filled the lavatory from the floor to the ceiling, but she saw no flames. While she was inspecting the lavatory, she inhaled some smoke and closed the door. The No.3 flight attendant then saw the No.2 flight attendant nearby and asked her to tell the flight attendant in charge of the situation. Upon being advised there was a fire, the flight attendant in charge instructed the No. 2 flight attendant to inform the captain and then to assist the No. 3 flight attendant in moving the passengers forward and in opening the eyebrow air vents over the passenger seats to direct air to the rear of the cabin. The flight attendant in charge then took the CO extinguisher and opened the lavatory door about three-quarters open. He also saw no flames, but he observed thick curls of black smoke coming out of the seams of the aft lavatory walls at the top of the wash basin behind the vanity and at the ceiling. He then proceeded "to saturate the washroom with CO'' by spraying the paneling and the seam from which smoke was seeping and spraying the door of the trash bin. He then closed the lavatory door.
At 19:02:40, the No. 2 flight attendant reached the cockpit and told the captain, "Excuse me, there's a fire in the washroom in the back, they're just ... went back to go to put it out." Upon being notified of the fire, the captain ordered the first officer to inspect the lavatory. The captain then donned his oxygen mask and selected the 100-percent oxygen position on his regulator. The first officer left the cockpit but did not take either smoke goggles or a portable oxygen bottle with him. (The airplane was not equipped with nor was it required to be equipped with self-contained breathing equipment or a full face smoke mask.) The first officer said that he could not get to the aft lavatory because the smoke, which had migrated over the last three to four rows of seats, was too thick. The flight attendant in charge told the first officer what he had seen when he opened the lavatory door, that he had discharged the CO2 extinguisher into the lavatory, and that he had not been able to see the source of the smoke before closing the door. He told the first officer, however, that he did not believe the fire was in the lavatory's trash container. The first officer told the flight attendant in charge that he was going forward to get smoke goggles. At 19:04:07, the first officer returned to the cockpit and told the captain that the smoke had prevented him from entering the aft lavatory and that he thought "we'd better go down." He did not tell the captain that the flight attendant in charge had told him that the fire was not in the trash bin. However, at 19:04:16, before the captain could respond, the flight attendant in charge came to the cockpit and told the captain that the passengers had been moved forward and that the captain didn't "have to worry, I think its gonna be easing up." The first officer looked back into the cabin and said that it was almost clear in the back. He told the captain, "it's starting to clear now," and that he would go aft again if the captain wanted him to do so. According to the captain, the first officer's smoke goggles were stored in a bin on the right side of the cockpit and were not easily accessible to the first officer while he was not in his seat. Since the first officer needed the goggles and since there was a hurry, the captain gave him his goggles and, at 19:04:46, directed him to go aft.
Two minutes later, while the first officer was out of the cockpit, the flight attendant in charge told the captain again that the smoke was clearing. The captain believed the fire was in the lavatory trash bin and decided not to descend at this time because he "expected it (the fire) to be put out." About 19:05:35, while the first officer was still aft to inspect the aft lavatory, the airplane experienced a series of electrical malfunctions. The master caution light illuminated, indicating that the airplane's left a.c. and d.c. electrical systems had lost power.
In the meanwhile, the first officer proceeded to the aft lavatory and put on the smoke goggles. The lavatory door felt hot to the touch, so he decided not to open it and instructed the cabin crew to leave it closed. At that time, he noticed a flight attendant signaling him to hurry back to the cockpit. The first officer returned to the cockpit and got into his seat, and at 19:07:11, he told the captain, "I don't like what's happening, I think we better go down, okay?" Then the master warning light illuminated and the annunciator lights indicated that the emergency a.c. and d.c. electrical buses had lost power. The captain's and first officer's attitude directional indicators tumbled. The captain ordered the first officer to activate the emergency power switch, thereby directing battery power to the emergency a.c. and d.c. buses. The attitude directional indicators' gyros began erecting, however, because of the loss of a.c. power, the stabilizer trim was inoperative and remained so during the rest of the flight. At 19:08:12, Flight 797 called the radar high sector controller at Indianapolis Center: "Mayday, Mayday, Mayday." The Louisville radar high sector controller acknowledged the call, and at 19:08:47, the flight told the controller that it had a fire and was going down. The controller told the flight that it was 25 nautical miles from Cincinnati and asked "can you possibly make Cincinnati." The flight answered that it could make Cincinnati and then requested clearance; it was then cleared to descend to 5,000 feet. At 19:09:05, Flight 797 reported that it was leaving FL330. The flight then told the controller that it needed to be vectored toward Cincinnati, that it was declaring an emergency, and that it had changed its transponder code to 7700 -- the emergency code. However, the transponder was inoperative due to the power loss.
The Louisville radar high sector controller directed the flight to turn to 060 degrees and told it that the Greater Cincinnati Airport was at "twelve o'clock at twenty miles." The Indianapolis Center's Lexington low altitude D (LEX-D) controller then called the approach controller at the Cincinnati Airport's Terminal Radar Control (TRACON) facility to alert him of an impending handoff in his southwest sector and later told the Cincinnati approach controller that he had "an emergency for you, Air Canada seven nine seven." The approach controller replied, "Zero six six two, thirty-five thousand." Zero six six two was the code assigned to Continental 383, a westbound flight at FL350. At 19:09:33, the LEX-D controller answered, "Yeah, thirty-three right now, he's twenty-five southwest." The approach controller replied, "Radar contact, okay." However, when the approach controller accepted the handoff of Flight 797, he had mistaken the radar beacon target of Continental Flight 383 as that of Flight 797. Shortly after he had accepted the handoff, the approach controller had notified the Cincinnati Airport tower local controller that he intended to land an Air Canada jet with an on board fire on runway 36. The tower's local controller alerted the airport fire station, and crash-fire-rescue (CFR) vehicles were dispatched and positioned for an emergency landing. The firefighters had also been advised that the airplane had electrical problems, that smoke was coming from the aft lavatory, and that there was smoke or fire in the rear of the airplane. At 19:10:01, almost coincident with the end of his message to the local controller, the LEX-D controller informed the approach controller of Flight 797's assigned 060° heading. At 19:10:25, Flight 797 contacted the Cincinnati approach controller, declared an emergency, and said that it was descending. The approach controller acknowledged and told the flight to plan for a runway 36 instrument landing system (ILS) approach and requested the flight to turn right to 090 degrees. He then realized the target he was observing was not responding and attempted unsuccessfully to assign a discrete transponder code to it in order to track it better. Thereafter, at 19:10:48, Flight 797 reported that it had a fire in its aft lavatory and that the cabin was filling with smoke. The controller asked the flight to "say the type airplane, number of people on board, and amount of fuel (on board)." The first officer answered that he would supply this data later because "I don't have time now." At 19:12:40, the approach controller called the Evansville/Nabb D controller on the landline to request assistance. Almost simultaneous with the call, he also observed an eastbound primary target and began to monitor it. At 19:12:44, the flight requested the cloud ceiling at the airport and the controller responded that the ceiling was "two thousand five hundred scattered, measure(d) eight thousand feet overcast, visibility one two (12) miles with light rain." The controller then decided that the eastbound target was Flight 797, and at 19:12:54, he requested the flight to "say altitude." Based on the target's position -- about 3 nmi east of runway 36's extended centerline and about 8 nmi south of its threshold -- and its reported altitude of 8,000 feet, that it was too high and too fast to land on runway 36. He decided to use runway 27L for landing, and used the primary target to monitor the flight and vector it toward the airport. At 19:13:38, after Flight 797 was unable to tell him its heading because its heading instruments were inoperative, the approach controller asked the flight to turn left. The controller said that this was an identification turn and that it was also designed to place the airplane closer to the airport. He then told the flight that this was a "no gyro" radar approach for runway two seven left ... If and cleared it to descend to 3,500 feet. He then told the flight that it was 12 nmi southeast of the Cincinnati Airport, cleared it to land on runway 27L, and informed it that the surface wind was 220 degrees at 4 knots. He informed the tower of the change of landing runways and the tower directed the fire department to position its vehicles along runway 27L. At 19:15:11, Flight 797 reported that it was level at 2,500 feet." The approach controller vectored the flight to runway 27L, and at 19:15:58, told it that it was 12 nmi from the airport. The flight descended to 2,000 feet, and the controller continued to supply range calls.
When the captain sighted the runway, he extended the landing gear. Since the horizontal stabilizer was inoperative, the captain extended the flaps and slats incrementally through the 0, 5, 15, 25, and 40-degree positions. He allowed his indicated airspeed to stabilize at each flap position as he slowed to approach speed. He flew the final approach at 140 KIAS and completed the landing. After touchdown, he made a maximum effort stop using extended spoilers and full brakes. Because of the loss of the left and right a.c. buses, the antiskid system was inoperative and the four main wheel tires blew out. The airplane was stopped just short of the intersection of taxiway J. After the captain completed the emergency engine shutdown checklist, both he and the first officer attempted to go back into the cabin and assist in the passenger evacuation, but were driven back by the smoke and heat. Thereafter, they exited the airplane through their respective cockpit sliding windows. After the airplane stopped, the left (L-1) and right (R-1) forward cabin doors, the left forward (L-2) overwing exit, and the right forward (R-2) and aft (R-3) overwing exits were opened, and the slides at the L-1 and R-1 doors were deployed and inflated. The 3 cabin attendants and 18 passengers used these 5 exits to evacuate the airplane. After the 18 passengers and 5 crewmembers left the airplane, the cabin interior burst into flames. Twenty-three passengers perished in the fire. Neither the passengers, crew, nor witnesses outside of the airplane saw flames inside the cabin before the survivors left the plane. The fuselage and passenger cabin were gutted before airport fire personnel could extinguish the fire.
PROBABLE CAUSE: "A fire of undetermined origin, an underestimate of fire severity, and conflicting fire progress information provided to the captain.
Contributing to the severity of the accident was the flight crew's delayed decision to institute an emergency descent."
Official accident investigation report
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not
display the exact flight path.
Distance from Dallas/Fort Worth International Airport, TX to Toronto International Airport, ON as the crow flies is 1916 km (1197 miles).