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Smoke or Fumes Removal on B747

Posted: Sat Mar 20, 2021 7:35 pm
by wiss
Hello everybody

The 747-400 QRH (which I got after buying the 747 made by PMDG) has a checklist named Smoke or Fumes Removal. There is a step in that list that caught my attention, which states that if there are severe smoke and fumes in the cabin, the cabin crew will be advised to open certain cabin doors. Obviously this procedure was designed to be made while the plane is still airborne.

The procedure states that before opening the doors, the plane must descend to 8500 feet or the minimum safety altitude of the area, and reduce its speed to 200 IAS or less. While I know that at this stage there is no pressure differential between the inside and the outside of the plane, and that such a low speed reduces the force of the air impacting the airframe, does the cabin crew member tasked with opening the door still needs to be physically strong? because there will still be a lot of resistance from the wind outside.

Also, does the cabin crew member doing this procedure need to be held by someone else, or restrained in order to not fall and hurt themselves because of the air that will rush inside from the outside? (yes, I know that in this case there will not be any kind of decompression, but the wind blowing seems that would still be quite strong)

I know that this procedure was seemingly attempted in the SA295 accident. Has it been done in any other incident? Is there any other large airliner that features a similar procedure that contemplates opening the doors midflight?

Thanks!

Re: Smoke or Fumes Removal on B747

Posted: Sat Mar 20, 2021 11:03 pm
by fr8mech
You really don’t open the door too far. The B747 door is, by far, the most complicated door I’ve every dealt with in maintenance. When you rotate the handle, the first few degrees of travel will pop the gates open, top and bottom. The 20 or so degrees of further travel will move the hinge side of the door into the airframe. As I recall, this is as far as the door needs to be ‘opened’ in the smoke evac procedure.

In fact, when I worked for Pan Am, one of the interior check items was to check for a 6’ish inch strap that was used to secure the door when popped open like this. “Secure” isn’t really the right word. More like restrained the door from opening further.

Re: Smoke or Fumes Removal on B747

Posted: Tue Mar 23, 2021 2:23 pm
by Ted65
The drill involves on instruction from the commander, to “crack” certain doors. One or two doors are used, this depends on the location of the smoke. I was type qualified as cabin crew on the 747 for 32 years. This was always a question in our annual recurrent training.