Author Topic: General Questions About The Case  (Read 374320 times)

Offline 73blazer

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Re: General Questions About The Case
« Reply #3300 on: May 06, 2022, 09:59:10 AM »
So why would the stairs not have been locked? The handle is two positions down and up. If you put it in the down position it should lock. So you must be saying the hydraulics are not enough to push the stairs all the way down into a locked position during flight. There's a video by MentourPilot on youboob and he explains some 727 mechanics used the stairs as an anti tipping device during certain loading operations or when messing with stuff on the tail. SO in a locked position they shouldn't move. He also says the pilots pre-flight use to include ensuring the arms on the stairs were all the way down and locked kinda implying sometimes they didn't lock even on the ground so I suppose getting to a locked position may not be easy to attain during flight, but Boeing says stairs can be "deployed" up to 300kts.
So your saying Anderson said only the amber stairs not up & locked light was on and NOT the green stairs down and locked? If he stated exactly which lights were on somewhere that would explain alot.
The rear cabin door is the pressure sealer, even though the plane was unpressurized I imagine some slight difference of pressure still happens and opening of this door during flight could create a pressure reading as well. I'd like to see more detail on the stairs mechanics and specs for the cylinders.
 

Offline Shutter

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Re: General Questions About The Case
« Reply #3301 on: May 06, 2022, 06:04:25 PM »
Several things.....

The 727 is not centered gravity wise when empty, yes, the stairs hold up the plane. They also use a pole when the stairs are up or inoperable. it just keeps the plane level while on the ground. reason, when the plane is empty the engines weight is greater in the back vs the front so it will tip with little weight change inside.

The stairs will not lock due to the wind load on them, or all the hijackers would of jumped from a locked position. the stairs were NEVER in the locked position. the crew would have to go to the back to retract them for landing. it just never happened.

The amber light on the engineers panel tells you the stairs are not locked. the green light tells you they are in the locked position. 305 never got a green light.

Pressure will register on the gauge, these gauges are used to pressurize the plane. they are very sensitive. you have a sealed tube, basically, any disruption will register. it's not much different than closing a door in the house and the curtains move. once air is introduced to a sealed area, disruption will occur. open the car door at 10 mph and then at 90 and watch the difference wind loads create. several thousand lbs will be pushing the stairs...

One of my trucks has a camper top on it. the actuators have a load capacity of 60 lbs. while on the highway they come down to almost level due to the wind load on them. it is what it is..
« Last Edit: May 06, 2022, 06:42:29 PM by Shutter »
 
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Offline georger

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Re: General Questions About The Case
« Reply #3302 on: May 06, 2022, 11:20:00 PM »
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Several things.....

The 727 is not centered gravity wise when empty, yes, the stairs hold up the plane. They also use a pole when the stairs are up or inoperable. it just keeps the plane level while on the ground. reason, when the plane is empty the engines weight is greater in the back vs the front so it will tip with little weight change inside.

The stairs will not lock due to the wind load on them, or all the hijackers would of jumped from a locked position. the stairs were NEVER in the locked position. the crew would have to go to the back to retract them for landing. it just never happened.

The amber light on the engineers panel tells you the stairs are not locked. the green light tells you they are in the locked position. 305 never got a green light.

Pressure will register on the gauge, these gauges are used to pressurize the plane. they are very sensitive. you have a sealed tube, basically, any disruption will register. it's not much different than closing a door in the house and the curtains move. once air is introduced to a sealed area, disruption will occur. open the car door at 10 mph and then at 90 and watch the difference wind loads create. several thousand lbs will be pushing the stairs...

One of my trucks has a camper top on it. the actuators have a load capacity of 60 lbs. while on the highway they come down to almost level due to the wind load on them. it is what it is..

well put, comprehensive . . . . .
 

Offline JAG

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Re: General Questions About The Case
« Reply #3303 on: May 07, 2022, 06:58:28 AM »
During the part of the sled test where one of the testers walked down the stairs and stood there, was it confirmed that the pressure gauge in the cockpit fluctuated?