KLM685
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Aviation Myths

Wed Jun 11, 2008 9:08 am

So a friend invited me to his radio program tomorrow and gave me the task of finding out some of the most common aviation myths around.

The first one is whether a door can be opened during flight. We all know it's impossible but what's the explanation behind it.

The second one is about Flight Simulator. Is it real that someone like an FS geek ( like me) would be capable of landing a real plane?

The third one would be: if a whole is opened at the middle of the flight, would the difference in pressurization make the airplane explode?


I've done some research about them and some were even inspired after watching Mythbusters. Would love to know some of your thoughts about it. If you have another myth please suggest!


Thanks!

Alonso
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Mir
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RE: Aviation Myths

Wed Jun 11, 2008 9:25 am



Quoting KLM685 (Thread starter):
The first one is whether a door can be opened during flight. We all know it's impossible but what's the explanation behind it.

Because the door is designed to open inwards before opening outwards. The pressure differential between the cabin and the outside air at altitude prevents this inward motion - the door is sealed tighter the higher you go.

Quoting KLM685 (Thread starter):
The second one is about Flight Simulator. Is it real that someone like an FS geek ( like me) would be capable of landing a real plane?

It's possible, but I certainly wouldn't want to be a passenger in the back. That applies for both the 747 and the 172.  Smile

Knowing how to program an FMC based on a LevelD or PMDG product is one thing. Actually flying the airplane is something that Flight Simulator cannot teach you.

Quoting KLM685 (Thread starter):
The third one would be: if a whole is opened at the middle of the flight, would the difference in pressurization make the airplane explode?

If the airplane were to explode, it would be because said hole created stress on the airframe that lessened its ability to withstand the pressure inside. The fuselage would then explode, though not with any fire or anything - it would just burst like a balloon. The DeHaviland Comet had a problem of structural fatigue which led to several such accidents. It got withdrawn from service pretty damn quick after that, and much has been learned from it and from other accidents.

The hole has to be in the right place. If it's from a door coming open (if you could get the door open), the plane would just decompress and that would be that. Same thing for a window being blown out, provided it didn't take any significant structure with it. Basically, it is theoretically possible, but very very unlikely, so don't hold your breath for it to happen (which you wouldn't want to do during a decompression anyway, lest you yourself explode  Wink ).

-Mir
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Starlionblue
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RE: Aviation Myths

Wed Jun 11, 2008 9:41 am

Have fun on the radio. I would take a chance to highlight the following if you can make it entertaining:
- Airliners are build around the principle that there should not be a single point of failure.
- Accidents with a single cause are rare.
- Aviation is extremely safe. Much safer than driving.
- Aviation myths are interesting, but they are typically propagated by people who know little about commercial aviation.

Quoting KLM685 (Thread starter):
The first one is whether a door can be opened during flight. We all know it's impossible but what's the explanation behind it.

Assuming the aircraft is pressurized, it is not possible because the door sits in the hole like a plug and is pushed against the jamb by the pressure differential. Like trying to suck a golf ball through a garden hose. In theory, you can open it if you pull hard enough, as in thousands of kilos of force. I don't know if the handle would hold. The corollary is that doors can be opened at low altitudes if the aircraft is not pressurized.

Special case: doors not of the plug type. For example cargo doors and some cabin doors (IIRC the DC-9 has one). Some notable accidents were the Turk DC-10 and that 747 where the hinges had bent.

Quoting KLM685 (Thread starter):
The second one is about Flight Simulator. Is it real that someone like an FS geek ( like me) would be capable of landing a real plane?

Very very very VERY theoretically yes, but only if:
- You treat it as serious simulation.
- (You use add-ons like PDMG to make it more realistic).
- You follow procedures while "playing".
- The plane is fine and the weather is fine.
- You have balls of steel. It's one thing to do in theory or even in a full motion sim, it's another to know lives are on the line.

In practice, I think it is be unlikely that all those conditions will be met.

Quoting KLM685 (Thread starter):
The third one would be: if a whole is opened at the middle of the flight, would the difference in pressurization make the airplane explode?

You mean a "hole". In general the answer is no. The air would simply rush out of the hole. But we have to subdivide the scenario:
- Bullet hole: the air would rush out but if the outflow valves are closed the aircraft can maintain pressurization. Plane lands safely.
- Blown out window: the air would rush out but if the outflow valves are closed the aircraft can maintain pressurization. Plane lands safely but if you were right next to it when it blew out you might be in danger.
- Big hole several meters wide like the Aloha 737 or UA 747 (both of which landed safely but with casualties). Now it starts becoming more dicey but the danger isn't so much from pressurization issues as it is about structure. As long as the structure doesn't fail, the control surfaces are not damaged (JAL 747) and you don't lose more than one redundant signal and/or hydraulic path (Sioux City DC-10), you should be ok.

[Edited 2008-06-11 02:54:25]
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FlyASAGuy2005
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RE: Aviation Myths

Wed Jun 11, 2008 9:45 am



Quoting KLM685 (Thread starter):
The second one is about Flight Simulator. Is it real that someone like an FS geek ( like me) would be capable of landing a real plane?

I'll second Mir. It sure would help if you had in-depth knowledge of the a/c systems from using PDMG/WILCO-PUB/Level-D/Phoenix Sim etc. but flying the thing is something totally different.
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dragon6172
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RE: Aviation Myths

Wed Jun 11, 2008 10:32 am



Quoting KLM685 (Thread starter):
The second one is about Flight Simulator. Is it real that someone like an FS geek ( like me) would be capable of landing a real plane?

Clear weather, calm wind, daylight hours, long wide runway, straight in approach, maybe a pilot "coach" on the radio, and hell, lets add in a chase plane, then sure I think your odds of this being successful go up. Start taking these away, then the chances of success go down. Especially if its night, IFR conditions!
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David L
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RE: Aviation Myths

Wed Jun 11, 2008 10:33 am



Quoting Mir (Reply 1):
Knowing how to program an FMC based on a LevelD or PMDG product is one thing. Actually flying the airplane is something that Flight Simulator cannot teach you.

Agreed. With some PMDG experience, there might be a chance to coax a healthy 744 to an autoland with no additional problems to contend with. I certianly wouldn't fancy hand-flying a real 747 to a manual landing on my first time at the controls.  eyepopping 
 
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Zkpilot
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RE: Aviation Myths

Wed Jun 11, 2008 11:28 am



Quoting KLM685 (Thread starter):
So a friend invited me to his radio program tomorrow and gave me the task of finding out some of the most common aviation myths around.

The first one is whether a door can be opened during flight. We all know it's impossible but what's the explanation behind it.

The second one is about Flight Simulator. Is it real that someone like an FS geek ( like me) would be capable of landing a real plane?

The third one would be: if a whole is opened at the middle of the flight, would the difference in pressurization make the airplane explode?


I've done some research about them and some were even inspired after watching Mythbusters. Would love to know some of your thoughts about it. If you have another myth please suggest!


Thanks!

Alonso

1)As others have mentioned a door can't be opened in flight due to the pressure differential... or in the case of the 747 it can be cracked open (for venting purposes) but can't be opened due to the windflow over the forward opening door.


2) Flight sim on a computer if enough time was spent on it then yes possible but sure would be interesting...
Flight sim trainer (ie ZFT sim) is effectively the same as flying an aircraft so if they could learn how to fly that then no problem at all...might not be the smoothest of landings however.

3) depends on the size of the hole... but an explosion? generally not in most circumstances... the plane would depressurise from anything bigger than a window right up to say 3m x 3m... after that the plane would likely break up and then possibly explode as the fuel tanks ruptured...thats a pretty extreme example however...
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HAWK21M
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RE: Aviation Myths

Wed Jun 11, 2008 11:40 am



Quoting KLM685 (Thread starter):
The first one is whether a door can be opened during flight. We all know it's impossible but what's the explanation behind it.

Depending if the Aircraft is a pressurised type or not  Smile

Quoting KLM685 (Thread starter):
The second one is about Flight Simulator. Is it real that someone like an FS geek ( like me) would be capable of landing a real plane?

Landing on the runway is the concern.

on the 3rd query.....Depends on the location of the damage.

regds
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pilotboi
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RE: Aviation Myths

Wed Jun 11, 2008 2:16 pm



Quoting KLM685 (Thread starter):
The first one is whether a door can be opened during flight. We all know it's impossible but what's the explanation behind it.

As many others have said, it's because of the pressure difference. I think this answer is best described with an example.

Let's say we're cruising at 30,000 feet. So standard pressure outside the cabin at this altitude is about 4.3 PSI. Now the cabin is pressurized so that it's similar to being at 8,000 feet, which is about 8.5 PSI. So the difference in pressure between the inside and outside of the aircraft is 8.5 - 4.3 = 4.2 PSI.

Now, let's take a standard aircraft door, roughly 6' x 3', or 72" x 36", or 2592 square inches. Multiply that by the force of pressure per inch, 4.2 PSI, and you get 10,866 lbs. So you have to be pretty damn strong to pull an aircraft door towards you in flight.
 
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RE: Aviation Myths

Wed Jun 11, 2008 3:43 pm



Quoting KLM685 (Thread starter):
would the difference in pressurization make the airplane explode?

Absolutely not. Never under any circumstances. Even the comet did not explode.

Reason is definitions: explosion is what happens when the burst occurs at a speed greater than the local speed of sound. An open can of gasoline does not explode. It burns very rapidly. Chemical compounds can burn at rates exceeding the speed of sound (in air) but an uncontained pneumatic overpressure will propagate at speeds approaching but not exceeding the speed of sound.

They may rend the fuselage asunder, with further damage being done by dynamic airload but they will not "explode" without the acceleration of explosives.

Quoting Starlionblue (Reply 2):
doors not of the plug type. For example cargo doors and some cabin doors (IIRC the DC-9 has one).

The DC-9 cargo doors were of plug type. They were hinged at the top and opened inward, remaining entirely within the pressure vessel. The only non-plug door on the DC-9 was the forward airstair door below the 1L door. It latched to lugs on the ladder and, reportedly the entry/galley floor was designed to collapse, trapping the stair to prevent extension in the event of the door blowing open. I cannot personally confirm this last part.
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RE: Aviation Myths

Wed Jun 11, 2008 4:10 pm



Quoting KLM685 (Thread starter):
The second one is about Flight Simulator. Is it real that someone like an FS geek ( like me) would be capable of landing a real plane?

I had a few goes on full motion sims before I had any real life licenses or real training. Made a decent job of it. Airliners are built to be easy to fly. I think a degree in aeronautical engineering could be considered cheating, though.  Smile I'd say a flight simmer who has put in good study time and has bothered to figure out how to fly a similar plane by the book on instruments will probably be able to get the aircraft to the airport and produce a crash which definitely leaves good hope for survival. Providing there aren't any failures to cope with etc, of course, StarLionBlue made a good list of ifs in reply #2.

A casual flight simmer, who just burns around the virtual sky having fun? Ahm, nope.

How about adding inability to take off from a conveyor belt and pendulum effect? Was it a three week show? Big grin
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chksix
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RE: Aviation Myths

Wed Jun 11, 2008 4:15 pm

Mythbusters on Discovery did all those myths.
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SlamClick
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RE: Aviation Myths

Wed Jun 11, 2008 4:27 pm



Quoting Chksix (Reply 11):
Mythbusters on Discovery did all those myths.

Perhaps they did, but they really, really SUCK at any experiment that isn't extremely straightforward. Their logic is often flawed and their science really poor. They clearly conduct their experiments for entertainment and not for actual establishment of fact. Case in point, the grossly uninformed "expert" pilot they recruited for the plane on a conveyor belt experiment.
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RE: Aviation Myths

Wed Jun 11, 2008 6:37 pm



Quoting Pilotboi (Reply 8):
Now, let's take a standard aircraft door, roughly 6' x 3', or 72" x 36", or 2592 square inches. Multiply that by the force of pressure per inch, 4.2 PSI, and you get 10,866 lbs. So you have to be pretty damn strong to pull an aircraft door towards you in flight.

You'd probably break the door handle/latch mechanism before the door budged Big grin
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KLM685
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RE: Aviation Myths

Wed Jun 11, 2008 6:40 pm

Guys, thanks for all your replies! They have all been really helpful as they complement one another really well.

So basically opening a door in flight is impossible.

A Flight Simulator geek just MIGHT be able to fly an airplane in case of an emergency. This depends of course on many scenarios which would be:
1. having a pilot over the radio giving you all the explanations
2. someone who had the time to read the real panel from the aircraft in question (in case there's no expert pilot at the radio)
3. In case there's no radio then it would be almost impossible to figure out.

But all in all theoretically impossible

Quoting Chksix (Reply 11):
Mythbusters on Discovery did all those myths.

Yes they did but I wanted the a.net point of view.

Quoting Starlionblue (Reply 2):
Have fun on the radio. I would take a chance to highlight the following if you can make it entertaining:
- Airliners are build around the principle that there should not be a single point of failure.
- Accidents with a single cause are rare.
- Aviation is extremely safe. Much safer than driving.
- Aviation myths are interesting, but they are typically propagated by people who know little about commercial aviation.

Thanks! I'll definately add this up.


Many thanks for all this replies!
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aogdesk
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RE: Aviation Myths

Wed Jun 11, 2008 7:01 pm

Another popular myth within the industry is that aircraft mechanics are highly respected.

 Wink Just kidding...have fun...
 
planewasted
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RE: Aviation Myths

Wed Jun 11, 2008 8:13 pm

Maybe interesting to mention that a twin engined plane can handle an engine failure in any phase of the take-off?
 
MD11Engineer
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RE: Aviation Myths

Wed Jun 11, 2008 8:34 pm



Quoting SlamClick (Reply 9):
Reason is definitions: explosion is what happens when the burst occurs at a speed greater than the local speed of sound. An open can of gasoline does not explode. It burns very rapidly. Chemical compounds can burn at rates exceeding the speed of sound (in air) but an uncontained pneumatic overpressure will propagate at speeds approaching but not exceeding the speed of sound.

Sorry to correct you, but "explosion" is the master term. It is dividend into "detonation", which is a chemical reaction producing gases, which propogate at a speed higher than sound (this also applies to the rather narrow reaction zone intthe explosive, actually just inside a supersonic shock wave, energy transfer between molecules happens through mechanical impact and not through heat). A typical example would be a dynamite. It doesn't need a tamping. The gases are released at such a speed, that the surrounding air can (through it's own inertia and incompressibility) cannot give way.
"Deflagration" is the other term, if the gases escape at less than speed of sound, the reaction zone is much wider and energy transfer between molecules happens through heat. In this casea typical example would be black powder. They need a good tamping to keep the gases together until a high pressure is reached, then the containment will give way at the weakest point.

During my blasting training, our instructor demonstrated the differences:
First he placed a pound of black powder on a brick and fired it. All that happened was a loud whoosh, a flame and a mushroom cloud of white smoke.
Then he placed some black powder into an empty food tin and placed a sencod, slightly bigger tin over it. There was a soft pop and the bigger tin flew into the air.
Finally he took a stick of a commercial ammonia nitrate dynamite, primed it, and placed it on top of the brick, without any tamping. There was a sharp, loud bang and the brick disintegrated into pebbles.

An explosion can also be caused by purely mechanical means as a sudden release of stored energy, e.g. in a bursting steam boiler.

Jan
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SlamClick
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RE: Aviation Myths

Wed Jun 11, 2008 9:03 pm



Quoting MD11Engineer (Reply 17):
An explosion can also be caused by purely mechanical means as a sudden release of stored energy, e.g. in a bursting steam boiler.

I've seen an old wooden barrel full of ox plates (shoes) pressed apart under the load. Yielding to the weight of the loose mass inside the staves had slipped the highest hoop and the upper hoops were slowly being pressed upwards as the barrel fell apart. I'd guess that this process probably took something like a hundred years to play out. Was this an explosion of this type?

How about my torso? Settling toward the bottom, it is. Explosion?

Okay, I'll accept your definitions. I'll argue with a journalist on this, but not an engineer.
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ALexeu
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RE: Aviation Myths

Wed Jun 11, 2008 9:08 pm

I've seen that A340 doors have a small window (if we can call it a window), under which is written that it must be opened before the door opens. Does this mean that we could open that small window in mid-air ?
 
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RE: Aviation Myths

Wed Jun 11, 2008 9:14 pm



Quoting SlamClick (Reply 18):
I'll argue with a journalist on this, but not an engineer.

Aw c'mon.....considering the background of the two of you, I was really looking forward to watching this skirmish from the sidelines.  Wink
 
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RE: Aviation Myths

Wed Jun 11, 2008 9:15 pm

Not exactly a pure aviation myth per se, but plenty of people toss around the old "1 in every 5 miles on an (American) interstate highway has to be straight, in order to be used as a landing strip in an emergency".

I can show you plenty of interstates where that's not the case.

Not to mention, that only applies to the US.  Smile
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moo
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RE: Aviation Myths

Wed Jun 11, 2008 9:55 pm



Quoting Vikkyvik (Reply 21):
Not exactly a pure aviation myth per se, but plenty of people toss around the old "1 in every 5 miles on an (American) interstate highway has to be straight, in order to be used as a landing strip in an emergency".

I think that myth originated from the fact that the Interstate system was originally funded because it gave the military better ways to move large number of troops around the country in emergency situations.

However, there *are* countries, such as Sweden, which do mandate road building with this in mind, and semi-regularly disperse their aircraft around the country to test wartime conditions.

http://www.canit.se/~griffon/aviation/img/saab/gripen/gall99/gripen_g50_roadb.jpg

Quoting KLM685 (Thread starter):
The second one is about Flight Simulator. Is it real that someone like an FS geek ( like me) would be capable of landing a real plane?

I know commercial pilots (747, A330) that have tried FS and said they couldn't land the aircraft they operate every week - theoretically a geek with thousands of hours behind him would have a leg up, but I wouldn't want to be on that aircraft.
 
Mir
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RE: Aviation Myths

Thu Jun 12, 2008 12:55 am



Quoting PlaneWasted (Reply 16):
Maybe interesting to mention that a twin engined plane can handle an engine failure in any phase of the take-off?

Careful, this isn't always true. For a commercial airliner, yes. But if the realm of little twin-engined trainer aircraft, performance really sucks with an engine failed, and you may not be able to climb at all depending on conditions.

As the saying goes, "the remaining engine is just enough to get you to the scene of the crash."

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RE: Aviation Myths

Thu Jun 12, 2008 1:05 am



Quoting SlamClick (Reply 12):
Case in point, the grossly uninformed "expert" pilot they recruited for the plane on a conveyor belt experiment.

At least he was proven wrong. But I will agree that Mythbusters have issues when it comes to complex subject matter.

Quoting KLM685 (Reply 14):

A Flight Simulator geek just MIGHT be able to fly an airplane in case of an emergency. This depends of course on many scenarios which would be:
1. having a pilot over the radio giving you all the explanations
2. someone who had the time to read the real panel from the aircraft in question (in case there's no expert pilot at the radio)
3. In case there's no radio then it would be almost impossible to figure out.

But all in all theoretically impossible

No. It is theoretically possible, but in practice extremely unlikely.

Quoting PlaneWasted (Reply 16):
Maybe interesting to mention that a twin engined plane can handle an engine failure in any phase of the take-off?

Indeed. I have heard lots of people get scared of "what if an engine breaks". I try to explain that there's a perfectly good one on the other side of the aircraft and it has more than enough power to get us where we need to go. This also ties into the "no single point of failure" thing.
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wn700driver
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RE: Aviation Myths

Thu Jun 12, 2008 3:43 am


The third one would be: if a whole is opened at the middle of the flight, would the difference in pressurization make the airplane explode?


I'll bite, as we just R&R'd some components related to this a few days back. Cabin pressurization is not a static event. One does not fill a cabin up with air and then take off. The Cabin is actually constantly being pressurized throughout the flight. In fact, on no system that I've ever worked with, is there any way to control this. Once the cabin is receiving air from the engines, the only way to modify or set the "altitude" one desires pressurization to relates to the outflow valve.

On most systems, this is a check (one way) valve, that may or may not be attached to a pressure regulator. On most a/c , you can actually see the outflow ports along the bottom of the fuselage. So, in a case of sudden decompression, an automated system would likely seal the outflow valve, as well as draw more bleed air in from the other available engines. For something like a bullet hole on up to something like a window blowing out, it is extremely improbable that the cabin depressurize more than a few percent before the system catches up (although venturi issues obviously present a degree of difficulty proportional to the size of the hole.)

For something like a door, or chunk of wall blowing out (Hawaii seems to have bad luck with those things. . .) you have much bigger problems than pressurization to worry about. Overhead Oxygen (supplied by impact resistant candles) will give you all the air you need, for longer than you'll probably need it. In that case, I'd worry first about any hydraulic lines or electric cables being severed/crimped, etc. . . If there were anything more than that to deal with, whatever caused the hole in the first place has probably already reaqquainted me with the dead relatives.
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MD11Engineer
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RE: Aviation Myths

Thu Jun 12, 2008 4:23 am



Quoting SlamClick (Reply 18):
Quoting MD11Engineer (Reply 17):
An explosion can also be caused by purely mechanical means as a sudden release of stored energy, e.g. in a bursting steam boiler.

I've seen an old wooden barrel full of ox plates (shoes) pressed apart under the load. Yielding to the weight of the loose mass inside the staves had slipped the highest hoop and the upper hoops were slowly being pressed upwards as the barrel fell apart. I'd guess that this process probably took something like a hundred years to play out. Was this an explosion of this type?

How about my torso? Settling toward the bottom, it is. Explosion?

Okay, I'll accept your definitions. I'll argue with a journalist on this, but not an engineer.

Slam,

IIRC, an explosion is defined as gases suddenly escaping, so I think your example with the barrel doesn't fit the definition.
The other definitions are those Iearned during my blasting and demolition training at the federal German civil defense school in Ahrweiler.

Jan
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SFOMB67
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RE: Aviation Myths

Thu Jun 12, 2008 5:29 am



Quoting Mir (Reply 1):
Quoting KLM685 (Thread starter):
The first one is whether a door can be opened during flight. We all know it's impossible but what's the explanation behind it.

Because the door is designed to open inwards before opening outwards. The pressure differential between the cabin and the outside air at altitude prevents this inward motion - the door is sealed tighter the higher you go.



Quoting Starlionblue (Reply 2):
Special case: doors not of the plug type. For example cargo doors and some cabin doors (IIRC the DC-9 has one). Some notable accidents were the Turk DC-10 and that 747 where the hinges had bent.

Several years ago I seem to remember an Airbus, maybe a 319 or 320, that during taxi-in after landing in Florida, a flt attendant cracked the door open and was pulled out and fell to the tarmack and was killed. Think the acft was still pressurized. I haven't actually open or shut these 319 or 320 doors, but they aren't like a Boeing door and wondered about opening one of these inflt?
Not as easy as originally perceived
 
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Starlionblue
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RE: Aviation Myths

Thu Jun 12, 2008 8:41 am



Quoting Sfomb67 (Reply 27):
Several years ago I seem to remember an Airbus, maybe a 319 or 320, that during taxi-in after landing in Florida, a flt attendant cracked the door open and was pulled out and fell to the tarmack and was killed. Think the acft was still pressurized. I haven't actually open or shut these 319 or 320 doors, but they aren't like a Boeing door and wondered about opening one of these inflt?

Still can't open them in flight. They are plug type. I'm guessing that the pressure differential in this case wasn't so great, the aircraft being at sea level.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
chksix
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RE: Aviation Myths

Thu Jun 12, 2008 8:59 am

Slam, I agree about MB but they are fun to watch and Kari is sweet  Wink

An old and probably too generalising definition of the terms around explosions I learned was:

Combustion - cm/sec
Explosion - m/sec
Detonation - km/sek

(relates to the velocity of gaseous expansion)
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dragon6172
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RE: Aviation Myths

Thu Jun 12, 2008 10:10 am



Quoting Sfomb67 (Reply 27):
Several years ago I seem to remember an Airbus, maybe a 319 or 320, that during taxi-in after landing in Florida, a flt attendant cracked the door open and was pulled out and fell to the tarmack and was killed. Think the acft was still pressurized. I haven't actually open or shut these 319 or 320 doors, but they aren't like a Boeing door and wondered about opening one of these inflt?

Typically when weight is on wheels the safety/overflow valve opens equaling the pressure. I have not read about the incident you mentioned, but I am not sure someone was sucked out of a "cracked" door.
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CosmicCruiser
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RE: Aviation Myths

Thu Jun 12, 2008 11:42 am



Quoting Vikkyvik (Reply 21):
but plenty of people toss around the old "1 in every 5 miles on an (American) interstate highway has to be straight, in order to be used as a landing strip in an emergency".



Quoting Vikkyvik (Reply 21):
Not to mention, that only applies to the US

I don't think that's true at all

Quoting Moo (Reply 22):
I think that myth originated from the fact that the Interstate system was originally funded because it gave the military better ways to move large number of troops around the country in emergency situations

Actually from all that i've read that applied originally to Route 66 after WWII.

Quoting Moo (Reply 22):
However, there *are* countries, such as Sweden, which do mandate road building with this in mind, and semi-regularly disperse their aircraft around the country to test wartime conditions.

Others as well...at least in the days of the other regime
 
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zeke
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RE: Aviation Myths

Thu Jun 12, 2008 11:56 am



Quoting Sfomb67 (Reply 27):
Several years ago I seem to remember an Airbus, maybe a 319 or 320, that during taxi-in after landing in Florida, a flt attendant cracked the door open and was pulled out and fell to the tarmack and was killed. Think the acft was still pressurized. I haven't actually open or shut these 319 or 320 doors, but they aren't like a Boeing door and wondered about opening one of these inflt?

That was an AA A300 which diverted into MIA on Nov 20, 2000.

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aogdesk
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RE: Aviation Myths

Thu Jun 12, 2008 1:20 pm



Quoting Moo (Reply 22):
However, there *are* countries, such as Sweden, which do mandate road building with this in mind, and semi-regularly disperse their aircraft around the country to test wartime conditions.

That's a great photo!! lol

Sven, please be careful crossing the street..Bjorn almost got hit by a MiG yesterday..... Smile
 
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Starlionblue
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RE: Aviation Myths

Thu Jun 12, 2008 2:32 pm



Quoting Aogdesk (Reply 33):
Sven, please be careful crossing the street..Bjorn almost got hit by a MiG yesterday....

I beg thee. My native Sweden has indigenous fighters. Sweden may have bought a cartload of old Russian APCs (which they are now selling off after some very costly mods) but they didn't buy any MiGs.  Wink
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
SlamClick
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RE: Aviation Myths

Thu Jun 12, 2008 2:44 pm



Quoting MD11Engineer (Reply 26):
an explosion is defined as gases suddenly escaping, so I think your example with the barrel doesn't fit the definition.

Well then. I guess we need to define 'suddenly' before we can resolve this. I mean just because it took longer than one fleeting human lifetime, don't you think it is a little short-sighted to call a process that takes a mere hundred years anything less than sudden?
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BAE146QT
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RE: Aviation Myths

Thu Jun 12, 2008 5:31 pm



Quoting SlamClick (Reply 9):
Reason is definitions: explosion is what happens when the burst occurs at a speed greater than the local speed of sound. An open can of gasoline does not explode. It burns very rapidly. Chemical compounds can burn at rates exceeding the speed of sound (in air) but an uncontained pneumatic overpressure will propagate at speeds approaching but not exceeding the speed of sound.

That really is a key distinction. An ex-military friend of mine (he served in the 60s as a demolition expert) told me that the difference isn't just semantic. It did take me a while to get the idea, since it's not intuitive. When something goes "bang", we generally think of it as an explosion and that conditioning happens in childhood. Oh, and the media of course.
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OPNLguy
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RE: Aviation Myths

Thu Jun 12, 2008 5:44 pm

Back to the centerline of the original topic, some other myths...

1. Airliners routinely run around with fully-fueled tanks... FALSE

2. Airliners intentionally dump toilet waste in-flight... FALSE

3. All airliners dump fuel in case of an emergency landing... FALSE

4. The pilot in command (PIC) is (in the USA) are solely responsible for planning routes, alternates,and fuel loads... FALSE

5. Every unscheduled landing is an emergency landing... FALSE

6. There are different kinds of "emergencies", such as procedurally-driven ones that are much more benign than "get-this-sucker-landed-ASAP-or we're-all gonna-die" types of emergencies... TRUE
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
aogdesk
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RE: Aviation Myths

Thu Jun 12, 2008 5:50 pm



Quoting Starlionblue (Reply 34):
I beg thee. My native Sweden has indigenous fighters. Sweden may have bought a cartload of old Russian APCs (which they are now selling off after some very costly mods) but they didn't buy any MiGs. Wink

I considered appropriately labeling the aircraft, but MiG sounded so much better than "Sven, please be careful crossing the street..Bjorn almost got hit by an indigenous fighter yesterday...."

And to think that I berate my wife for not knowing the difference between a 757 and an A300 after all these years.

 Wink
 
SlamClick
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RE: Aviation Myths

Thu Jun 12, 2008 6:12 pm



Quoting OPNLguy (Reply 37):
3. All airliners dump fuel in case of an emergency landing... FALSE

Deadheaded into SFO early one morning and vapor was streaming off the outboard ends of the flaps. A kid in front of me asked his dad what it was and his dad explained that they 'had to dump fuel so they could land" Descending through a deep overcast in the back end of a MadDog one day and the guy behind me was 'explaining' to his girflfiend how they would find the airport: "They have sonars and scanners and stuff" Okay, good enough, I guess.

Myths:

7. Both pilots sit there with both hands on the yoke and "fly" the airplane together. - False except for Lufthansa Airbus. "Priority RIGHT"

8. Admiring stares follow airline pilots through the terminal. - Oh, wait, that is a pilot myth.

9. The flight attendant who stayed in her room instead of going out with the rest of the crew is really hot for the fat old married captain. - Oops, another pilot myth.


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vikkyvik
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RE: Aviation Myths

Thu Jun 12, 2008 6:20 pm



Quoting Moo (Reply 22):
I think that myth originated from the fact that the Interstate system was originally funded because it gave the military better ways to move large number of troops around the country in emergency situations.

 checkmark 

That is pretty much what I have heard also.

It definitely was funded with an eye toward wartime conditions, and troop mobility.

Quoting CosmicCruiser (Reply 31):
I don't think that's true at all

It's not. Hence a myth  Smile

Quoting CosmicCruiser (Reply 31):
Actually from all that i've read that applied originally to Route 66 after WWII.

That may be, but it was also used as a reason to fund the new Interstate Highway system. Route 66 was part of the older US Highway system, which the interstates, for most intents and purposes, replaced.
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Jetlagged
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RE: Aviation Myths

Thu Jun 12, 2008 6:57 pm

They don't call it "explosive decompression" for nothing. Compressed air does act in an explosive way. Pressurised water does not. That's one reason why they used a water tank to test the Comet fuselages at Farnborough in the 1950s. Same stresses, same fatigue, but a lot less dangerous when the fuselage eventually cracks open. Pressurised air expands rapidly when it is released. Water does not.

As a non-pilot who has flown a lot of full flight simulators I know I can safely get one down on the runway as smooth as any qualified pilot, even in bad weather. But doing it for real is an entirely different matter, unless all the automatics are working correctly. The only time I landed an aircraft for real (a little Cessna 152) I nearly froze with the combination of fear and adrenalin.

People only exposed to MSFS wouldn't stand much of a chance, even having practiced on the PMDG 747 in advance. A PPL who also used MSFS might get away with it.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
BAE146QT
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RE: Aviation Myths

Thu Jun 12, 2008 9:41 pm

Quoting SlamClick (Reply 39):
A kid in front of me asked his dad what it was and his dad explained that they 'had to dump fuel so they could land" Descending through a deep overcast in the back end of a MadDog one day and the guy behind me was 'explaining' to his girflfiend how they would find the airport: "They have sonars and scanners and stuff" Okay, good enough, I guess.

These are what Terry Pratchett calls "lies to children". The reasons are different, but the motivation is always the same - to provide reassurance.

In your first case, the father did not want to admit ignorance, (or perhaps even believed he was correct). Either way, the effect was to reassure the child.

In your second case, the guy probably knew that his girlfriend was uneasy. Hs explanation would have served to calm her. And if you think about it, it also probably served to calm him too. He might have convinced himself he was right to alleviate the fear of not knowing what was happening to the aircraft during an apparently normal flight.

:::EDIT::: With all due respect, I imagine that SlamClick knows this already. He's met more passengers than I have. I'm just extrapolating on the theme for the sake of completeness.

Quoting Jetlagged (Reply 41):
As a non-pilot who has flown a lot of full flight simulators I know I can safely get one down on the runway as smooth as any qualified pilot, even in bad weather. But doing it for real is an entirely different matter, unless all the automatics are working correctly. The only time I landed an aircraft for real (a little Cessna 152) I nearly froze with the combination of fear and adrenalin.

I am a simmer as well as a real-world pilot. Until I flew and later landed a real (light) aircraft, I thought it would be a cake-walk. I was wrong. Whether I took to the experience of flying for real naturally is irrelevant. But no PC flight sim lets you fly with your ass and your peripheral vision. A real aircraft requires you to.

[Edited 2008-06-12 14:46:19]
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Jetlagged
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RE: Aviation Myths

Thu Jun 12, 2008 10:15 pm



Quoting BAe146QT (Reply 42):
I am a simmer as well as a real-world pilot. Until I flew and later landed a real (light) aircraft, I thought it would be a cake-walk. I was wrong. Whether I took to the experience of flying for real naturally is irrelevant. But no PC flight sim lets you fly with your ass and your peripheral vision. A real aircraft requires you to.

Absolutely. I was totally unprepared for the complete loss of forward vision in a piston single in flare. My instructor, who clearly felt I had been doing OK by myself up to that point, hadn't warned me. Landing a Boeing is easier (in the sim I hasten to add) with no engine to get in the way of the view.

I often wonder why Cessna and Piper made the glareshields on their aircraft so high in the pilot's eyeline. I flew in a Beagle Pup once, and it was like being in a goldfish bowl in comparison (and it had a proper control column too).
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
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Starlionblue
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RE: Aviation Myths

Thu Jun 12, 2008 11:42 pm

Quoting Aogdesk (Reply 38):
I considered appropriately labeling the aircraft, but MiG sounded so much better than "Sven, please be careful crossing the street..Bjorn almost got hit by an indigenous fighter yesterday...."

Hehe. MiG does sound cooler.

Quoting BAe146QT (Reply 42):
These are what Terry Pratchett calls "lies to children". The reasons are different, but the motivation is always the same - to provide reassurance.

In your first case, the father did not want to admit ignorance, (or perhaps even believed he was correct). Either way, the effect was to reassure the child.

Now this is truly OT but I don't believe "lies to children" are really a good idea unless the child is very young. When I was a kid and my dad didn't know the answer to this kind of question, he would send me to fetch the encyclopedia (he had one of those 20 volume jobs). If we weren't home, this would be the first order of the agenda. Then we would find the answer together. This led to both skill in finding information an d a life long curiosity on my part.

[Edited 2008-06-12 16:45:05]
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
Mir
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RE: Aviation Myths

Thu Jun 12, 2008 11:51 pm



Quoting OPNLguy (Reply 37):
6. There are different kinds of "emergencies", such as procedurally-driven ones that are much more benign than "get-this-sucker-landed-ASAP-or we're-all gonna-die" types of emergencies... TRUE

Fact: The last flight you were on might have had an emergency and you never knew about it, because it wasn't a big deal.

-Mir
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OPNLguy
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RE: Aviation Myths

Fri Jun 13, 2008 12:07 am



Quoting Mir (Reply 45):
Fact: The last flight you were on might have had an emergency and you never knew about it, because it wasn't a big deal.

You don't have to convince me--I've been dispatching for nearly 30 years...  Wink
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
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Moose135
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RE: Aviation Myths

Fri Jun 13, 2008 12:46 am



Quoting BAe146QT (Reply 42):
I am a simmer as well as a real-world pilot. Until I flew and later landed a real (light) aircraft, I thought it would be a cake-walk. I was wrong. Whether I took to the experience of flying for real naturally is irrelevant. But no PC flight sim lets you fly with your ass and your peripheral vision. A real aircraft requires you to.

Not only that, but in the "standard" scenario - pilots incapacitated, Flight Simmer comes to the rescue - I think you would be more apt to wet yourself then land an airliner safely...there's no "reset" button on a 757  Smile

While it's been years since I've been in the cockpit with any regularity, I have flown everything from single engine props to T-38s to KC-135s, yet I can't land worth a damn on a PC flight sim.
KC-135 - Passing gas and taking names!
 
aogdesk
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RE: Aviation Myths

Fri Jun 13, 2008 1:35 am



Quoting BAe146QT (Reply 42):
In your second case, the guy probably knew that his girlfriend was uneasy. Hs explanation would have served to calm her. And if you think about it, it also probably served to calm him too. He might have convinced himself he was right to alleviate the fear of not knowing what was happening to the aircraft during an apparently normal flight.

Parents doing their best to "explain" to their kids is one thing. Guys trying to "explain" to their girlfriends/wives is a different animal, they're doing it to impress. I used to work at a restaurant that was a few hundred feet away from BUF airport RWY 5/23. I can't tell you how many times I'd hear "Honey, thats a 747....." and I'd look out the window to see anything from a DL 757 to an EA L1011. I wanted to do the BULLSHIT cough, but most of the time I just chuckled.
 
Mir
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RE: Aviation Myths

Fri Jun 13, 2008 2:42 am



Quoting OPNLguy (Reply 46):
You don't have to convince me--I've been dispatching for nearly 30 years...

I meant "you" in the general sense.  Wink

-Mir
7 billion, one nation, imagination...it's a beautiful day

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