Discovery Mayday

[shamrock104]

Anyone see the Mayday show on Discovery last night. It featured the Air Canada DC9 fire back in 1983. I felt sorry for the crew who were criticised for not realising the imminent danger and taking decisive action fast enough. It got me thinking about the Swissair disaster a couple of decades later with the smoke in the cockpit and again the delay due to fuel dumping ete etc. I am no expert on these matters and I would never be a armchair judge but should it not be mandatory on the first sign of smoke no matter how small it appears to get the aircraft landed as soon as possible? According to the programme several good changes were made after this disaster.

[boeingboy]

My question for those who have the experiance is - why would the crew not depressurize the plane? The smoke would get sucked out the outflowvalve and the pass would have O2 from the masks. And the lack of O2 may even put out the fire.

Even if they depress at lower altitudes - say 14,000 it should still clear up enough that they can see out the front window.

[Lands Like Brick]

If you decompress would you not be feeding the fire more oxygen?

[Pilot_adam]

I watched it twice yesterday and had the same questions as boeingboy in mind.
i believe that a/c were not prepared for such accident at the time,they did not have fire detectors in the restrooms. The captain new that if O2 finds its way into the cabin the gases might ignite (that is what happened when they opened the door upon landing) and then the a/c would blow up in the air.(the captain mentioned that the procedures of fire in cabin prohibited the use of oxygen masks).

The ironic thing is that I had an electrical fire in my car while driving on a hwy last weekend, it amazed me how fast the smoke filled the car and how the smell had a burning nature (I don't think it would be survivable in a 2 seater a/c).

I could barley breath with the windows and the sunroof wide open,pulled to the side and got out asap.

I personally think the crew did an amazing job by getting the a/c on the ground asap.


Adam

[Goose757]

If you decompress would you not be feeding the fire more oxygen?

Uh, no. Where would the oxygen be comming from?

[C-FABH]

If you decompress would you not be feeding the fire more oxygen?

Uh, no. Where would the oxygen be comming from?

The sky?

[Goose757]

If you decompress would you not be feeding the fire more oxygen?

Uh, no. Where would the oxygen be comming from?

The sky?

I'm pretty sure you're being sarcastic, but in case you aren't, if you're at 10,000ft+ there isn't much oxygen to begin with.

If I'm not mistaken, in case of an electrical fire with smoke in the cockpit, (in a pressurized aircraft), one of the first courses of action after trying to determine the cause is to dump the cabin.

[Icebound]

I am no expert on these matters and I would never be a armchair judge but should it not be mandatory on the first sign of smoke no matter how small it appears to get the aircraft landed as soon as possible?

There was a "smoke in the cabin" incident out of Pearson just this past Wednesday, and he just turned it back to YYZ right away... CADORS report 2007O0733

[Sasktel]

Uh, no. Where would the oxygen be comming from?

The sky?

I'm pretty sure you're being sarcastic, but in case you aren't, if you're at 10,000ft+ there isn't much oxygen to begin with.

If I'm not mistaken, in case of an electrical fire with smoke in the cockpit, (in a pressurized aircraft), one of the first courses of action after trying to determine the cause is to dump the cabin.

Umm... actually there is just as much oxygen at 10,000ft as at ground level, oxygen is not afraid of heights.

[Hotel Tango]

The sky?

I'm pretty sure you're being sarcastic, but in case you aren't, if you're at 10,000ft+ there isn't much oxygen to begin with.

If I'm not mistaken, in case of an electrical fire with smoke in the cockpit, (in a pressurized aircraft), one of the first courses of action after trying to determine the cause is to dump the cabin.

Umm... actually there is just as much oxygen at 10,000ft as at ground level, oxygen is not afraid of heights.

umm... actually there isn't just as much oxygen at 10,000ft as at ground level.

[Rockie]

The sky?

I'm pretty sure you're being sarcastic, but in case you aren't, if you're at 10,000ft+ there isn't much oxygen to begin with.

If I'm not mistaken, in case of an electrical fire with smoke in the cockpit, (in a pressurized aircraft), one of the first courses of action after trying to determine the cause is to dump the cabin.

Umm... actually there is just as much oxygen at 10,000ft as at ground level, oxygen is not afraid of heights.

Actually 10,000 ft equates to 700 millibars pressure versus 1013 millibars at sea level. That means there is approximately 30% less oxygen at 10,000 ft per unit of volume than there is at sea level.

Less oxygen = less fire.

With any kind of fire, depressurizing the cabin below 10,000 ft is accomplished anytime smoke becomes a problem to vent it outside.

[C-FABH]

I'm not being sarcastic. I certainly understand the atmospheric levels are different, but if you depressurize and activate the pax O2, it would feed the fire. Afterwards, if you descended for an emergency landing (below 10,000 feet, right? Unless you're landing on Everest) it would have the same effect.

I can't see a more positive outcome, except for stuffing the checklist and doing a spiral dive to the nearest airport.

[pika]

Umm... actually there is just as much oxygen at 10,000ft as at ground level, oxygen is not afraid of heights.

Ever wonder why we pressurize airplanes Sasktel?


This thread generates good discussion (the internet does have a use!) but the whole issue is reduced to a judgement call(s) under a very particular set of circumstances. When you are on fire the rules go out the window. Here are some lessons from past experiences.

HISTORICALLY, If you have a cabin or cargo fire and aren't able to extinguish it within TWO MINUTES from it's start time you WILL NOT BE ABLE TO EXTINGUISH IT.

Further, if you have an inextinguishable fire you have historically, ONLY between 4 & 14 minutes to land/ditch & evacuate - if you fail to do this IN THIS TIME FRAME the fire will have destroyed the aircraft.

http://www.airborne.org/flying/forum3.h ... ight%20797

[Rowdy]

Fire in or on an airplane = scary shit.

I've read a lot on that incident and I think the crew did a pretty good job when it came down to it.

[lilfssister]

Good shows, those Mayday's. I watch most of the aviation ones just to see what's going on at the other end of the mic in those (hopefully I'll never see) situations.

[Sasktel]

Forget it..

[Edi]

At 15000 feet or FL380 if yours engines are still running, that means it's enough oxigen to feed the cabin fire too.
If it's something to blame, blame the flight att. They quit the plane and left the pax to fight allones for their lives. At least this is what I saw on the doc.

[CD]

Here's the final accident report from the NTSB:

NTSB/AAR-86/02
Covington, Kentucky
Air Canada
June 2, 1983

3. CONCLUSIONS
3.1 Findings

1. The airplane was registered, equipped, and maintained in accordance with Canadian regulations, and it was operated within the United States in accordance with applicable Federal Aviation Regulations.

2. The flightcrew and the cabin crew were qualified and trained in accordance with Canadian regulations and Air Canada requirements. Each crewmember had received the off-duty times prescribed by Canadian regulations.

3. A fire propagated through the amenities section of-the aft lavatory and had burned undetected for almost 15 minutes before the smoke was first noticed.

4. The fire was not set deliberately nor was it the result of an explosive or incendiary device.

5. The Safety Board could not identify the origin of the fire.

6. The first malfunction to evidence itself to the flightcrew was the simultaneous tripping of the three flush motor circuit breakers, about 11 minutes before the smoke was discovered. The flightcrew did not consider this to be a serious problem.

7. The smoke in the aft lavatory was discovered by a flight attendant. The smoke was reported to the captain as a fire.

8. The source of the smoke was never identified either by the flight attendants or the first officer. The captain was never told nor did he inquire as to the precise location and extent of the “fire,” which had been reported to him. Crewmember reports that the fire was abating misled the captain about the fire severity and he delayed his decision to declare an emergency and descend.

9. Because of the delayed decision to descend, the airplane lost the opportunity to be landed at Louisville. Had the airplane been landed at Louisville, it could have been landed 3 to 5 minutes earlier than it actually did land at Cincinnati. The delayed decision to descend and land contributed to the severity of the accident.

10. A faulty ATC handoff did not delay significantly Flight 797's landing at Greater Cincinnati Airport.

11. The fire consumed the lavatory walls, propagated into the ceiling, and then began to move forward. Smoke, toxic fumes, and heated gases began to enter the cabin, spread forward, and collect along the ceiling of the cabin.

12. The flight attendants’ passing out wet towels to the passengers and instructing them to breathe through the towels or through articles of clothing aided in the survival of some of the passengers.

13. The first officer turned off the air conditioning and pressurization packs in the belief that the airflow was feeding the fire. The resulting loss of circulation accelerated the accumulation of smoke, heat, and toxic gases in the cabin and likely decreased the time available for evacuation.

14. Three of the four overwing exit windows were opened by designated passengers who had been selected and briefed to open them by the flight attendants.

15. When the airplane stopped, smoke had filled the cabin and visibility within the cabin was almost nonexistent 2 to 3 feet above the cabin floor.

16. A flashfire occurred within the cabin within 60 to 90 seconds after the doors and overwing window exits were opened. Flames from this fire were not evident until after the survivors had left the airplane. Flames from the original fire never were evident within the airplane or to persons on the ground.

17. This was a survivable accident.

3.2 Probable Cause

The National Transportation Safety Board determines that the probable causes of the accident were a fire of undetermined origin, an underestimate of fire severity, and misleading fire progress information provided to the captain.

The time taken to evaluate the nature of the fire and to decide to initiate an emergency descent contributed to the severity of the accident.

[matrix]

Ever wonder why we pressurize airplanes Sasktel?

Sasktel is right.

I think some of you need to go back to groundschool.

The percentage of oxygen is constant throughout the atmosphere. The reason why we pressurize is because there is less pressure at higher altitudes. This pressure is needed to "push" the oxygen into your lungs.

[Rockie]

Ever wonder why we pressurize airplanes Sasktel?

Sasktel is right.

I think some of you need to go back to groundschool.

The percentage of oxygen is constant throughout the atmosphere. The reason why we pressurize is because there is less pressure at higher altitudes. This pressure is needed to "push" the oxygen into your lungs.

Except we're not talking about percentages, we're talking about quantity. There is the same percentage of oxygen on the fringe of space too, but hardly the quantity wouldn't you say?

[Rudder Bug]

actually there is just as much oxygen at 10,000ft as at ground level, oxygen is not afraid of heights.

Don't know but did you ever try to light a match at 10,000 ft? Maybe not oxygen but matches are definitely affraid of heights. They just don't burn

[185/310]

I think one of the main things that was over looked was the communication between the FA and the flight deck. The way I understood it from the show is that a passenger complained about a funny smell, and notified the FA. The whole tail end knew about the smoke (fire), and the FA was going back to extinguish what he could before he notified the flight deck. Why wasent the flight deck notified right away? Maybe that would of came them just a bit more time, every sec counts. Hard to judge from the show though. It just seemed weird, at one point the FO says lets go down, and then the FA comes up and says its all fine.

[CD]

I think one of the main things that was over looked was the communication between the FA and the flight deck. The way I understood it from the show is that a passenger complained about a funny smell, and notified the FA. The whole tail end knew about the smoke (fire), and the FA was going back to extinguish what he could before he notified the flight deck. Why wasent the flight deck notified right away? Maybe that would of came them just a bit more time, every sec counts. Hard to judge from the show though. It just seemed weird, at one point the FO says lets go down, and then the FA comes up and says its all fine.

Here is some more information from the factual report that I linked to above:

At 1851:14 eastern daylight time, 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. (The motor is a three-phase alternating current (a.c.) motor; each phase incorporates a circuit breaker for protective purposes.) 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 1859:58, the captain again tried unsuccessfully to reset the three circuit breakers. According to the cockpit voice recorder (CVR), he told the first officer that the circuit breaker(s), “Pops as I push it.”

About 1900, a passenger seated in the last row asked the No. 3 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. The No. 2 flight attendant testified that she did not remember if she had been told there was smoke or fire in the lavatory; however, when she reached the flight attendant in charge she told him that there was a fire in the lavatory.

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 ames, 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 1902:40, 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 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 1904:07, 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 1904:16, 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. At 1904:23, 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 1904:46, directed him to go aft. The first, officer also testified that the captain and he “did not discuss the type of fire at all” during the time he was in the cockpit before he went to the lavatory the second time.

At 1906:52, 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 testified that he believed the fire was in the lavatory trash bin and that he did not decide to descend at this time because, “I expected it (the fire) to be put out.”

In the meanwhile, the first officer proceeded to the aft lavatory and put on the smoke goggles. He testified that he had intended to open the door to see what the situation was inside, but when he discovered that the lavatory door felt hot to the touch, 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 1907:11, he told the captain, “I don’t like what’s happening, I think we better go down, okay?” The captain testified that, from the first officer’s voice inflection, he knew that the first officer believed the fire was out of control and that he had to descend immediately.

About 1905:35, while the first officer was aft to inspect the aft lavatory, the airplane had experienced a series of electrical malfunctions. According to the captain, the master caution light illuminated, indicating that the airplane’s left a.c. and d.c. electrical systems had lost power. At 1906:12, the captain called Indianapolis Center and requested the Center to standby because the flight had an “electrical problem.” About 30 to 45 seconds later, the Louisville high radar sector controller working Flight 797 lost the flight’s radar beacon target. The controller then directed the computer to track all primary targets. Flight 797’s position was then depicted on the scope by a plus sign and associated data block.

About 1907:41, after the first-officer had returned to the cockpit, 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.

[flyinphil]

Keep in mind folks that most of what we do and the way we act and communicate today is based on past failures.

At the time of this incident, we still allowed pax and crew to smoke onboard. Cabin fire would be a little less detectable. There were not smoke detectors. Captain's were the only authority as CRM did not exist between the pilots let alone the back end crew. It took HUGE balls to challenge the Skipper.

A lot of "whatifing" and "whynotting" going on here but you have to put it in the context of the day as well.

The crew did a fine job once the severity of the situation became apparent.

Now, what is your action plan if this happens to you at 30W? If you haven't thought about it, you ought to.

[yycguy]

Didn't see the documentary, however I'm finding the discussion about oxygen vs altitude amusing.

ie.

At 15000 feet or FL380 if yours engines are still running, that means it's enough oxigen to feed the cabin fire too.

Keep in mind at FL380 your engines have the advantage of several turbine compressor stages in order to boost the air pressure well beyond what is necessary to create ignition.

And as for dumping the cabin...

Dumping the cabin has two advantages, one is to reduce the amount of oxygen by lowering the ambient air pressure to slow the fire's burn rate (no it won't put out the fire), and the other is to create an airflow pattern in the cabin that will draw air and smoke through the outflow valves located in the aft pressure bulkhead away from the cockpit.

And finally no aircraft manual will encourage dumping the cabin above 10,000ft in the event of a cabin fire, because doing so will release the oxygen masks further feeding the fire. The manual will direct the pilot to descend below 10,000 ft before dumping the cabin.