DIA
Topic Author
Posts: 3053
Joined: Sun Jan 28, 2001 2:24 pm

Number Of Exit Doors: I Don't Get It

Sat Jan 17, 2004 12:45 am

Take a look at this DC-8, it has more exit doors than the 747!
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Photo © Michael Haywood

I never understood exit door standards. . .when to have less. . .when to have more. . .widebody or narrowbody. . .how does someone determine these necessary, or unnecessary? I do know it has a lot to do with emergency drill times for the pax to deplane. . .but just look at that DC-8! C'mon. . .what gives?

Was it different during the DC-8 production era compare to now? I think there are probably other examples of a/c that are similar to hte DC-8 example.
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Guest

RE: Number Of Exit Doors: I Don't Get It

Sat Jan 17, 2004 12:52 am

S-A-F-E-T-Y

 Laugh out loud hehehe
 
DIA
Topic Author
Posts: 3053
Joined: Sun Jan 28, 2001 2:24 pm

RE: Number Of Exit Doors: I Don't Get It

Sat Jan 17, 2004 12:58 am

"S-A-F-E-T-Y"

If that were the case. . .I guess this DC-8 is the safest a/c ever!  Big grin
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usnseallt82
Posts: 4727
Joined: Tue Jan 06, 2004 4:49 pm

RE: Number Of Exit Doors: I Don't Get It

Sat Jan 17, 2004 12:59 am

In-flight garbage disposal. Or passenger disposal, whichever side you're looking at it from.  Big thumbs up

Cheers!
Crye me a river
 
PiedmontGirl
Posts: 1112
Joined: Mon Nov 24, 2003 2:39 am

RE: Number Of Exit Doors: I Don't Get It

Sat Jan 17, 2004 1:01 am

There are several reasons for this. For one thing, the FAA standards on how far apart the exits could be changed. Also, the materials that the slides are made of became tougher and the inflation mechanisms of the slides became more reliable.

Also, the slides on the big birds like 74s are double width. You can send two people at a time down side by side. The slides on the DC-8s were single width, just like the slides on 737s, 312s and what not.

Hope this helps.  Smile
 
ultrapig
Posts: 566
Joined: Fri Dec 12, 2003 11:38 pm

RE: Number Of Exit Doors: I Don't Get It

Sat Jan 17, 2004 1:04 am

I believe that there must be sufficient doors for the full load to exit within 90 seconds with 3/4 of the doors operating. I may be off on the actual numbers but if you are as old as I you will remember that when the 747 was about to be certified there was a picture in the press of 490 boeing employees each with a numbered vest having a grand time sliding off shoots in certitification tests.
 
northstardc4m
Posts: 2724
Joined: Fri Apr 28, 2000 11:23 am

RE: Number Of Exit Doors: I Don't Get It

Sat Jan 17, 2004 1:05 am

you have to remember its not the number of seats per exit, its the time it takes to get all the passengers and crew out through half of them. Narrow body aircraft tend to have more exits per passenger because the single aisle slows down movement in the cabin. Also most of the time, there are more seats per row per aisle on a narrowbody than on a widebody (narrowbody will be 5 or 6, widebody 4 or 5). The more per row, the less room there is in the aisle, the longer it takes everyone to get to an exit.

I recall a story i heard once, about back when the 747 was entering service, Boeing demonstrated a 747 and 707 evacuation side by side. They used 4 exits on the 747, and all 8 on the 707. With 150 on the 707 and 450 on the 747, everyone was off the 747 10 seconds before the last was off the 707.
Those who would give up Essential Liberty to purchase a little Temporary Safety, deserve neither Liberty nor Safety.
 
PiedmontGirl
Posts: 1112
Joined: Mon Nov 24, 2003 2:39 am

RE: Number Of Exit Doors: I Don't Get It

Sat Jan 17, 2004 1:09 am

Ultrapig:

I believe that there must be sufficient doors for the full load to exit within 90 seconds with 3/4 of the doors operating.

You numbers are correct. When an airplane is certified it is within 90 seconds with 3/4 of the exits operational. Also, when an airline is getting ready to put an airplane into operation, they have to demonstrate the carrier's ability to hit those numbers.
 
flashmeister
Posts: 2671
Joined: Fri Apr 28, 2000 4:32 am

RE: Number Of Exit Doors: I Don't Get It

Sat Jan 17, 2004 6:33 am

Isn't it true that the number of doors isn't really relevant, but the number of paths out doors that's measured (along with distance, time, etc.)? Meaning that if you have bigger doors that can accomodate 2 people at once, that counts as two paths, where a slimmer door that's single-person-at-once is only 1?

My understanding was that the paths out the door play a bigger role than the number of aisles, seats per aisle, etc.
 
Nicollo
Posts: 48
Joined: Mon Jan 05, 2004 12:29 am

RE: Number Of Exit Doors: I Don't Get It

Sat Jan 17, 2004 9:00 am

There is a difference between =Door Exits and Exits.

On this aircraft shown, there are a total of 16 Exits.

Main cabin "door" exits are primary exits, while window exits are secondary exits. However, When you must evac., asses out side conditions - No smoke, no fire, no water!

On this aircaft type they're, 10 Door exits and 6 window exits... (don't forget to count the cockpit window exits that can be utilized as exits even though they're not primary).

The more exits the better to get you out  Smile



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