Things I always wanted to know as a passenger
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Things I always wanted to know as a passenger
I am a regular passenger and always wondered about the following:
1. What does the announcement " Doors to manual and cross check" mean?
2. You use wing flaps land the aircraft, why not use them for take off?
3. The pre-flight briefing makes great play on life jackets when landing on water. But what are the chances of survival of the aircraft on water when those engines under the wing dig into the water and disturb the aircarft attitude.
Would love to know
Thank you
1. What does the announcement " Doors to manual and cross check" mean?
2. You use wing flaps land the aircraft, why not use them for take off?
3. The pre-flight briefing makes great play on life jackets when landing on water. But what are the chances of survival of the aircraft on water when those engines under the wing dig into the water and disturb the aircarft attitude.
Would love to know
Thank you
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Peter, #1 I don't know, but I'd assumed it's to do with disarming the slides before the doors open, in order that they don't do their thing when they're not needed.
Regarding #2 - we do, except they're deflected much less on take off than on landing. Have a good look next time and you'll notice it. The settings for take off are tradeoff between getting off the runway ASAP and climb gradient. More flaps on takeoff equals less runway used but a shallower climb. For landing, the flaps are there to provide added drag.
As for #3 I understand that aircraft have successfully managed it, but in fairness I'd be reaching for the duty free rather than a lifejacket. We have no meaningful training in getting the thing onto water in one piece. Rather than worry about lifejackets, I'd just keep the seatbelt on, you're much more likely to cop an injury from turbulence.
Regarding #2 - we do, except they're deflected much less on take off than on landing. Have a good look next time and you'll notice it. The settings for take off are tradeoff between getting off the runway ASAP and climb gradient. More flaps on takeoff equals less runway used but a shallower climb. For landing, the flaps are there to provide added drag.
As for #3 I understand that aircraft have successfully managed it, but in fairness I'd be reaching for the duty free rather than a lifejacket. We have no meaningful training in getting the thing onto water in one piece. Rather than worry about lifejackets, I'd just keep the seatbelt on, you're much more likely to cop an injury from turbulence.
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*disclaimer*i'm not a hostie*
'doors manual' is on landing to ensure the slides don't deploy when they are opened (especially if opened from the outside as it is not possible to see if they are armed or not - just a big noise and the worlds biggest inflatable doll appearing in your airbridge!) i presume 'cross check' is to double check they are disarmed
flaps ARE used for take off - there are 'take off' and 'landing' flap settings.
putting your life jacket on is a good distractor from thinking about how much it's going to hurt when you're going to hit the water at 500mph.
'doors manual' is on landing to ensure the slides don't deploy when they are opened (especially if opened from the outside as it is not possible to see if they are armed or not - just a big noise and the worlds biggest inflatable doll appearing in your airbridge!) i presume 'cross check' is to double check they are disarmed
flaps ARE used for take off - there are 'take off' and 'landing' flap settings.
putting your life jacket on is a good distractor from thinking about how much it's going to hurt when you're going to hit the water at 500mph.
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1 It means disarm the slides so they wont go off when the doors open. Then the crew member at the opposite door must check this has been done.
2. We do, just normally not as much. The last bit we use for landing creates a lot more drag so whilst the few extra knots we can slow down is good for landing it would actually impair take off. The less flap the less drag, you'll need more runway but will climb faster.
3. Many pax survived the Ethiopian 767 ditching, many of those that died survived the impact but inflated their lifejackets before getting out hindering their escape. There have also been several aircraft off ends/sides of runways into water in the past.
2. We do, just normally not as much. The last bit we use for landing creates a lot more drag so whilst the few extra knots we can slow down is good for landing it would actually impair take off. The less flap the less drag, you'll need more runway but will climb faster.
3. Many pax survived the Ethiopian 767 ditching, many of those that died survived the impact but inflated their lifejackets before getting out hindering their escape. There have also been several aircraft off ends/sides of runways into water in the past.
Paxing All Over The World
Cross checking that an emergency slide HAS been selected to manual is vital as the cost of 'blowing the slide' is very high. Not least as the aircraft will be off duty until it gets a new one fitted. Even if the a/c is at a maintenance base, that could take many hours.
The 'flap' is an movable extension to the wing. When an a/c is going slowly, if the wing is larger it makes it improves all sorts of things. Once the machine is going faster, the flaps are retracted as they are not needed. As you have heard, they also add 'drag'. This is in the very last part of the descent.
The main occasions when water and survival work out is a low speed event. This would normally be where there is a stretch of water in close proximity to the airfield. So that, if the departure fails (very badly!!) then you will be entering the water at a relatively slow speed and, as mentioned above, if the machine fails the landing and overruns the end of the field and enters the water. If a machine enters/touches water at high speed, the result will be the same as if it did so on hard land.
The 'flap' is an movable extension to the wing. When an a/c is going slowly, if the wing is larger it makes it improves all sorts of things. Once the machine is going faster, the flaps are retracted as they are not needed. As you have heard, they also add 'drag'. This is in the very last part of the descent.
The main occasions when water and survival work out is a low speed event. This would normally be where there is a stretch of water in close proximity to the airfield. So that, if the departure fails (very badly!!) then you will be entering the water at a relatively slow speed and, as mentioned above, if the machine fails the landing and overruns the end of the field and enters the water. If a machine enters/touches water at high speed, the result will be the same as if it did so on hard land.
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Things I always wanted to know as a passenger
Thank you everyone for your replies
You have answered my questions.
I appreciated your humour
Thanks
Peter
You have answered my questions.
I appreciated your humour
Thanks
Peter
I only flew "Go" one round trip but they had 3 crew on a 737. It slightly amused me when they went through the "cross check" bit. There was one crew member at the front who simply set both doors and then cross checked him/herself.
Given that I suspect most locos have the same cc staffing the cross check bit seems slightly superfluous.
Given that I suspect most locos have the same cc staffing the cross check bit seems slightly superfluous.
Given that I suspect most locos have the same cc staffing the cross check bit seems slightly superfluous.
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As for #3 I understand that aircraft have successfully managed it, but in fairness I'd be reaching for the duty free rather than a lifejacket.
putting your life jacket on is a good distractor from thinking about how much it's going to hurt when you're going to hit the water at 500mph.
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If the doors areopened from the outside and the doors are still in automatic the slide will not deploy.They will only deploy if opened from the inside of the aircraft when still in automatic.
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airbus- you are incorrect. The B737 has a manual selection of arming and disarming the doors. You open an armed 737 door from the inside or the outside and you will get a surprise!
There is always someone who knows little and criticises!- 'cross check' is a valid call even on a 3 crew aeroplane. Why couldn't you just ask, rather than state a critical opinion on the basis of little knowledge, Hartington?
When I joined BOAC, I received regular training and demonstration films of experimental ditching of a large VC10 model in a water tank, together with extensive instruction of wave formations and how to handle ditching with regard to wave direction and wind effect. Done the right way, very little damage will occur- the engines are designed to come off easily and pass under the wing for aircraft like 747. It is vital to be slow and to avoid a wingtip digging-in as in the Ethiopian 767 which ditched wing down. Planes will float like corks, especially if the wing is intact and reasonably empty of fuel. On the top of wings is a nice ring to take a line from the cabin and provide a base from which to get people onto the wing and launch liferafts. It will work, and with little structural damage. It has several times. There was even a Japan Airlines DC8 that ditched into Tokyo Bay. It was recovered and repaired and actually flew again as a passenger plane.
There is always someone who knows little and criticises!- 'cross check' is a valid call even on a 3 crew aeroplane. Why couldn't you just ask, rather than state a critical opinion on the basis of little knowledge, Hartington?
When I joined BOAC, I received regular training and demonstration films of experimental ditching of a large VC10 model in a water tank, together with extensive instruction of wave formations and how to handle ditching with regard to wave direction and wind effect. Done the right way, very little damage will occur- the engines are designed to come off easily and pass under the wing for aircraft like 747. It is vital to be slow and to avoid a wingtip digging-in as in the Ethiopian 767 which ditched wing down. Planes will float like corks, especially if the wing is intact and reasonably empty of fuel. On the top of wings is a nice ring to take a line from the cabin and provide a base from which to get people onto the wing and launch liferafts. It will work, and with little structural damage. It has several times. There was even a Japan Airlines DC8 that ditched into Tokyo Bay. It was recovered and repaired and actually flew again as a passenger plane.
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Last trip I sat on a 738 in row 1:
Doors to automatic: Take the little bar off it's hangar on the door and clip it to the floor. Put the little orange tape across the window
Doors to manual: unclip from floor and clip into hangar on door, remove orange tape.
So I'm picking it wouldn't matter which side the door was opened from, and that the sole purpose of the orange tape is to indicate to person outside NOT to pull the handle.
The question I've always wanted to ask, but never dared (for fear of being escorted from the cabin in handcuffs and sent straight to a well known bay, never to return...)
Is there some kind of interlock stopping someone pulling the door in the cruise? It would seem deceptively easy for some nutjob to head for the toilet, then yank the handle at the last minute! However, if there's an interlock, who makes sure it's disengaged when it all goes wrong (prior to the big thump) - would seem flight crew would be more preoccupied attempting to avoid big thump.
Actually, I think I may have just answered my own question: is it just a case of the internal pressurisation being enough to hold the door against the seal harder than any person can pull?
Doors to automatic: Take the little bar off it's hangar on the door and clip it to the floor. Put the little orange tape across the window
Doors to manual: unclip from floor and clip into hangar on door, remove orange tape.
So I'm picking it wouldn't matter which side the door was opened from, and that the sole purpose of the orange tape is to indicate to person outside NOT to pull the handle.
The question I've always wanted to ask, but never dared (for fear of being escorted from the cabin in handcuffs and sent straight to a well known bay, never to return...)
Is there some kind of interlock stopping someone pulling the door in the cruise? It would seem deceptively easy for some nutjob to head for the toilet, then yank the handle at the last minute! However, if there's an interlock, who makes sure it's disengaged when it all goes wrong (prior to the big thump) - would seem flight crew would be more preoccupied attempting to avoid big thump.
Actually, I think I may have just answered my own question: is it just a case of the internal pressurisation being enough to hold the door against the seal harder than any person can pull?
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just what i was thinking - apart from a slight resistance, the girt bar in a 73 is really hard to detect if it's still hooked into the floor.
the dangers of assumption when jumping types.
and yes, there is a pressure switch that stops the door handle from being opened if there is more px inside the cabin than out, however, some doors (most pax doors on big jets) are plug type, and couldn't be opened against the pressure anyway - they have a flap at top and bottom to allow them to be fitted out the hole. the main cargo door on boeings though is not a plug door - is held closed by big hooks.
the dangers of assumption when jumping types.
and yes, there is a pressure switch that stops the door handle from being opened if there is more px inside the cabin than out, however, some doors (most pax doors on big jets) are plug type, and couldn't be opened against the pressure anyway - they have a flap at top and bottom to allow them to be fitted out the hole. the main cargo door on boeings though is not a plug door - is held closed by big hooks.
Paxing All Over The World
If I recall correctly, the offset in PSI on the door being pushed OUTWARDS from the cabin and ONTO it's seating is so high that you would need to pull in excess of 200lbs towards you. Maybe more?
Certainly, any time that you hear about pax 'wrestling for the handle' the newspaper reporting will be wrong! It is true that pax nearby will become agitated but, afterwards, the crew will explain it to the pax.
Certainly, any time that you hear about pax 'wrestling for the handle' the newspaper reporting will be wrong! It is true that pax nearby will become agitated but, afterwards, the crew will explain it to the pax.
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I'm sure if you worked it out (I can't be arsed), but with a pressure differential of up to 8 lbs/sq in, on a bloody great big bit of pax door, that's a whole lot more than 200 lbs of force required!
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Calculate- door about 78 inches x 36 inches (minimum) x 8 pounds Sq. in= 22,464 pounds pressure on that door, holding it against the stops. I would quite happily stand watching as the worlds most strongest man tried to wrestle with that. You don't need interlocks, and indeed most doors don't have them. The plug door has to open inwards first, so you need to defeat that pressure, before the door can be open- not just slide it past the stops to open. The handle mechanism isn't anywhere near strong enough. Makes for good scenes in movies though.
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I beleive the lights are dimmed on t/o and landing, when it is dark/getting dark, is so that if you DID have to leave the a/c in a hurry your eyes are already adjusted to the dark outside. Leaving a brightly lit area into a dark one, you know that it takes a few seconds for your eyes to adjust.