Planetfurry BBS Forum Index Planetfurry BBS
Forums for Planetfurry Site Members and more
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   DonateDonate   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Aerospace techno talk
Goto page 1, 2  Next
 
Post new topic   Reply to topic    Planetfurry BBS Forum Index -> Aslaug
View previous topic :: View next topic  
Author Message
The Silver Coyote
Registered User


Joined: 09 Nov 2003
Posts: 491
Location: Rogue River Valley, Oregon

PostPosted: Wed Jul 06, 2005 11:33 pm    Post subject: Aerospace techno talk Reply with quote

DF Thompson said
Quote:
Ok well all the techno aerospace talk went right over my head its still nice to know.


I would have posted this on the "Transitions" thread, but it's locked, or at least was while I was looking at it.

Someone mentioned decompression with respect to possible injury. Explosive decompression is very injurious, not only to passengers but also to the aircraft. This can occur due to some airframe failure, on board fire, accidental or intentional explosion, or external forces such as hostile arms fire or bird strikes.

Controlled decompression is just that, controlled so the pressure change is gradual and painless. Done properly, passengers might not even be aware that the decompression was happening until they started feeling short of breath from the high altitude.

<grins> I'm sure this will be a nowhere thread, but I'm enough of a verbose character that I needed to say it. I had meant to in my longer post that DF referred to, but forgot. I was probably distracted by that red vixen I live with...

<tips leather hat to the big cat>

SC

_________________
=====
Tread Lightly and Sing To The Sky
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger
Nameless
Site Owner
Site Owner


Joined: 06 Sep 2002
Posts: 1368
Location: Vienna, Austria

PostPosted: Thu Jul 07, 2005 1:36 am    Post subject: Re: Aerospace techno talk Reply with quote

The Silver Coyote wrote:
Controlled decompression is just that, controlled so the pressure change is gradual and painless. Done properly, passengers might not even be aware that the decompression was happening until they started feeling short of breath from the high altitude.

If you are perfectly healthy. If you have any problems with your ears (or have a cold, ...) then even the normal "decompression" as a plane ascends and the pressure changes from the outside pressure at 0 meters to in-flight pressure (AFAIK about the same pressure as you have at 2000 meters (6000 feet)) within a few minutes gives plenty of passengers problems.
Even a controlled decompression will probably happen more quickly than that. It won't suck your eyes out of their sockets, but your eardrums may well hurt like hell.

_________________
I'm a nut, but there are those who appreciate me for it.
Back to top
View user's profile Send private message Send e-mail Visit poster's website AIM Address
Aslaug
Site Owner
Site Owner


Joined: 04 Jan 2005
Posts: 1861
Location: Slagelse, Denmark

PostPosted: Thu Jul 07, 2005 2:05 am    Post subject: Reply with quote

I am not sure why the other thread was locked. I don't remember locking it, at least. But, as happy moderator, I have now reopened it Smile
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
Cateagle
Site Owner
Site Owner


Joined: 20 Nov 2000
Posts: 1004
Location: Ft. Worth, TX

PostPosted: Thu Jul 07, 2005 8:29 pm    Post subject: Reply with quote

The problem with decompression, even controlled decompression, is the loss of oxygen partial pressure in the lungs. Even under controlled conditions, a decompression requires the pilot to get down quickly to an altitude where the oxygen partial pressure is enough to keep consciousness going. That incident with the golfer's Learjet a few years ago is a pretty good illustration of that as it was a slow decompression and rendered the flight crew and passengers unconscious before they realized what was happening.
_________________
"But the wildest of all the wild animals was the Cateagle. He walked by himself and all places were alike to him."
-- With apologies to Rudyard Kipling
Back to top
View user's profile Send private message Send e-mail Visit poster's website AIM Address Yahoo Messenger MSN Messenger
The Silver Coyote
Registered User


Joined: 09 Nov 2003
Posts: 491
Location: Rogue River Valley, Oregon

PostPosted: Thu Jul 07, 2005 10:35 pm    Post subject: Reply with quote

<grins>

Wow, I didn't think my techno-nerd thread would get off the ground. So if we're gonna beat this horse to death, I want another shot at some input.

<thinks>

Oops. Sorry, Filly. Guess I could have worded that better...

Anyway, Cateagle said
Quote:
That incident with the golfer's Learjet a few years ago is a pretty good illustration of that as it was a slow decompression and rendered the flight crew and passengers unconscious before they realized what was happening.


I remember that incident. The Lear 35 slowly decompressed somewhere up around 40,000 feet. (See http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001212X19931&key=1 ) As I recall the supposition was that the pax and crew suffered the onset of hypoxia slowly, such that they weren't aware that they were in trouble until it was too late, if they ever knew at all. Quite sad, actually.

In the context of our Filly's story the situation wasn't as dire as that of the Lear 35 crew. Our heroines and their chartered crew were in the vicinity of 15,000 feet above Virginia on a warm summer afternoon. True, at that altitude the crew is legally required to use supplimental oxygen, and for not doing that either the crew ought to be cited by the FAA or be slapped around by Zig Zag for bending the law a bit.

<nods towards Nameless> And yes, even healthy furs would notice a gradual decompression while level at 15,000 feet. Their ears would tell them they were ascending rapidly by popping to equalize pressure. Any fur that had respiratory problems, cardio problems, or other physical impairments that would be susceptible to moderate loss of oxygen pressure in the lungs could suffer discomfort or experience temporary or even permanent injury.

As the oldest fur on that plane was probably the skipper himself, I was comfortable with the chapter as written. Our heroines are quite young and healthy, as far as I know, and given their behavior towards and... ummm... activity with the unoccupied members of the flight crew during the climate control failures and descent, I'd say that no ill effects were felt.

How the captain and first officer fared after learning what they missed out on is another story, one we may be thankful was not revealed to us. I always have a problem watching grown furs cry...

SC

_________________
=====
Tread Lightly and Sing To The Sky
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger
Aslaug
Site Owner
Site Owner


Joined: 04 Jan 2005
Posts: 1861
Location: Slagelse, Denmark

PostPosted: Thu Jul 07, 2005 10:39 pm    Post subject: Reply with quote

The Silver Coyote wrote:
How the captain and first officer fared after learning what they missed out on is another story, one we may be thankful was not revealed to us. I always have a problem watching grown furs cry...SC


I'm gonna tell Annie...
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
Cateagle
Site Owner
Site Owner


Joined: 20 Nov 2000
Posts: 1004
Location: Ft. Worth, TX

PostPosted: Thu Jul 07, 2005 10:58 pm    Post subject: Reply with quote

15,000 feet is adequate without pressurization. Combat aircraft, even without oxygen were routinely there in the 30's as were a number of the unpressurized airliners of that era; for example, the DC-3 operates quite comfortably there and is most definitely not pressurized. Actually, the first pressurized airliners didn't come along 'til the late 1930s, though the first experiments with pressurized aircraft took place in the mid-1930s.

Sure, I've been on the engineering side of aerospace for 30+ years; I enjoy the tech side of it. *chuckle* Why do you think my main character and friend in FTW are both in that business? You write what you know. Very Happy

_________________
"But the wildest of all the wild animals was the Cateagle. He walked by himself and all places were alike to him."
-- With apologies to Rudyard Kipling
Back to top
View user's profile Send private message Send e-mail Visit poster's website AIM Address Yahoo Messenger MSN Messenger
The Silver Coyote
Registered User


Joined: 09 Nov 2003
Posts: 491
Location: Rogue River Valley, Oregon

PostPosted: Fri Jul 08, 2005 10:27 am    Post subject: Reply with quote

Cateagle said
Quote:
You write what you know.


<smiles, nodding enthusiastically> Indeed we do...

With that kind of dangling carrot in front of my nose I suppose I'll have to follow some links to your stuff sometime soon.

Thanks,

SC

_________________
=====
Tread Lightly and Sing To The Sky
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger
Cateagle
Site Owner
Site Owner


Joined: 20 Nov 2000
Posts: 1004
Location: Ft. Worth, TX

PostPosted: Fri Jul 08, 2005 3:48 pm    Post subject: Reply with quote

SC, it also blends over somewhat into where the characters from From The Wings appear in Rava's Story, as well as in their other appearances here and there (PM me if you want the full list).
_________________
"But the wildest of all the wild animals was the Cateagle. He walked by himself and all places were alike to him."
-- With apologies to Rudyard Kipling
Back to top
View user's profile Send private message Send e-mail Visit poster's website AIM Address Yahoo Messenger MSN Messenger
The Silver Coyote
Registered User


Joined: 09 Nov 2003
Posts: 491
Location: Rogue River Valley, Oregon

PostPosted: Mon Aug 15, 2005 10:48 pm    Post subject: Reply with quote

The recent crash of Helios Airways flight ZU522 would unfortunately seem to lend our discussion here an example. However, at the time I write this, there are more questions than answers. Some things point to a rapid decompression of the 737-300's cabin at 34,000 feet, yet fighter pilot eye-witnesses claim they saw at least two people moving about in the cabin while at the same time seeing the copilot slumped at the controls and the pilot altogether absent.

I pray this wasn't a botched terrorist act.

Hopefully the CVR and FDR (cockpit voice recorder and flight data recorder) survived the crash well enough to yield useful data. They've been found, but found damaged. Too, the crew and craft may have been incapacitated for such a duration of time that the CVR (an "endless loop" recording device) may have recorded over the actual events leading up to the crash.

Our Filly's story has progressed well beyond the aviation part (to my chagrin), so perhaps this will be the last post here, unless somefur else has something...

SC

_________________
=====
Tread Lightly and Sing To The Sky
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger
James R. Lane
Registered User


Joined: 10 Nov 2002
Posts: 134

PostPosted: Mon Aug 15, 2005 10:59 pm    Post subject: Reply with quote

The Silver Coyote wrote:
The recent crash of Helios Airways flight ZU522 would unfortunately seem to lend our discussion here an example. I pray this wasn't a botched terrorist act.


Like you, I have my doubts as to the first simple reason for the crash. Something smells. Now the news is saying that the first autopsy subjects were ALIVE when the plane crashed. This tells me that the cabin did NOT "simply lose pressure, killing the plane's load of people and crew"... Sad

You and I both know enough about decompression effects for the bullshit alarms to be screaming their electronic heads off---

Think

_________________
James R. Lane
author of
"Redeeming Factors"
and
"Lifetimes"
Back to top
View user's profile Send private message Visit poster's website
anthony
Site Owner
Site Owner


Joined: 12 Nov 2001
Posts: 1304
Location: Norway

PostPosted: Tue Aug 16, 2005 2:32 am    Post subject: Reply with quote

I thought that Mythbusters proved quite definitely that it takes a pretty big hole to get explosive decompression?

A hole that size would have been immediately obvious to the fighter pilots.
(The 737-300 isn't that large so it's easy to get a good overview)

And if the air stops circulating, that won't knock out the pilots immediately.

Now, those text messages, THEY really have me puzzled...

If it was as cold as they seem to indicate, it's bl**dy impossible to type any message on a modern cell-phone. Dialling a number, yes, but all those keypresses?

On the other paw, Helios has a rather checquered history when it comes to safety and training...
(not as bad as Spantax was, but still)
A couple of years ago a chartered flight landed here in Norway and was alerted by the tower that there was smoke coming from one of the engines and that they should evacuate the plane.

The 'evacuation' was done by one crewmember walking into the cabin and telling people to 'get out', then getting out him/herself, leaving the passengers to get out as best they could. Some ended up using the emergency exit over the wing ON THE SIDE WITH THE SMOKE.
Luckily, the smoke was later shown to be from hydraulic fluid leaking onto the hot brakes...

Oh, and only one of the cabin-crew spoke any Scandinavian language at all...

_________________
"My name's Lion, Anthony Lion"
A fur with a license to purr...
---
Like my Avatar?
Why not surf over to www.micecomics.com and tell Mary what a stellar job she did...
Back to top
View user's profile Send private message Visit poster's website
Tigermark
Site Owner
Site Owner


Joined: 18 Apr 2003
Posts: 855
Location: Hopkinsville, KY

PostPosted: Tue Aug 16, 2005 2:34 am    Post subject: Reply with quote

I agree, you two, something is rotten in Cyprus. There are rumors abounding, and it'll take a bit for the facts to come out. Last i heard they were speculating if the CVR would be salvagable, it was so badly damaged. Also, if there were folks moving, and still alive, over 30 minutes after the decompression, what happened? Did the emergency O2 run out while the passengers made a futile attemp to gain access to the cockpit after the flight crew went south? Did all the oxygen systems fail, or only the flight deck one, and a partial failure in the passenger cabin? Was this a botched takeover attempt? Also of note, the F-16's that intercepted and flew alongside of this aircraft never saw the pilot, only the copilot slumped in his seat. Where had the pilot gone? At last report, they had not found his body in the wreckage yet, either.

Lots of questions, and very few factual answers yet. Let's see what developes.

Tigermark (Also prayers and condolences to the families and friends of those who lost their lives in this.)

_________________
Tiger, tiger, burning bright...
http://www.planetfurry.com/~tigermark
Back to top
View user's profile Send private message Visit poster's website AIM Address Yahoo Messenger
anthony
Site Owner
Site Owner


Joined: 12 Nov 2001
Posts: 1304
Location: Norway

PostPosted: Tue Aug 16, 2005 2:38 am    Post subject: Reply with quote

And now they've arrestedd the man who claimed to have received the SMS message from his cousin. It seems his cousin never was on the plane, and also, never sent any message.
Why someone would lie about that, though, I can't understand.

_________________
"My name's Lion, Anthony Lion"
A fur with a license to purr...
---
Like my Avatar?
Why not surf over to www.micecomics.com and tell Mary what a stellar job she did...
Back to top
View user's profile Send private message Visit poster's website
The Silver Coyote
Registered User


Joined: 09 Nov 2003
Posts: 491
Location: Rogue River Valley, Oregon

PostPosted: Tue Aug 16, 2005 11:33 am    Post subject: Reply with quote

I'm not real educated when it comes to the 737 and it's FDR. Is one of the hundred-and-some things it monitors cabin pressure and temperature?

You're right, there's too many odd things about that crash and the accounts leading up to it. I never did put much stock in the cousin text messaging... that sounded pretty weak from the start. But those fighter pilots unable to see half the flight crew, incapacitated or otherwise, that puzzles me. Was the pilot of the 737 in the cabin? Why? What happend to prevent him from returning to the flight deck? Why did the O2 masks deploy if there was no evidence of a rapid decompression (hole in the aircraft, broken windows, ice / fog on the windows).

I wonder if something happened to the air quality in the cabin that prompted the crew to deploy the O2 masks manually. This leans very much towards a terrorist act of some sort, or perhaps some sort of in-cabin fire that the crew managed to contain before being overcome by toxic smoke? Who knows...

I hope the CVR is salvageable, and that it contains useful data. I hope the FDR can similarly give the investigators something to go on. As James and Anthony both alluded to, something is *very* wrong with this crash. Air crew don't just go missing in mid-flight, and unless the aircraft comes apart in pieces there's usually enough time for the flight crew to dive to an altitude more conducive to survival before hypoxia and oxygen deprivation become acute. Yep,James, my BS alarm went off almost from the moment I heard about the 737 going down, but I was trying to absorbe more information before I went ballistic in response to it.

Unfortunately information is slow in coming, and much of it appears to be contradictory in nature. I guess Tigermark has the best idea for now, pray for the dead and the surviving families, and for an eventual determination of the cause so that we may ensure that it doesn't happen again.

SC

_________________
=====
Tread Lightly and Sing To The Sky
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger
Display posts from previous:   
Post new topic   Reply to topic    Planetfurry BBS Forum Index -> Aslaug All times are GMT - 4 Hours
Goto page 1, 2  Next
Page 1 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum


Powered by phpBB © 2001, 2005 phpBB Group