Oct 1, 2013, 6:01 pm
Last edit by: unavaca
tl;dr: yes
http://www.flyertalk.com/forum/21535032-post24.html
Originally Posted by UA MOC
On all [737] aircraft there is a power limiting system in place to prevent passengers from overloading the system. Bottom line, this is not a house outlet.
Excessive power demands can shut off an outlet, a seat group, or even an entire grid column.
The in-seat power system also seems to employ some sort of power creep system. At the start of a flight you might have a laptop plugged into every seat, but after a while the system will start to shut off some outlets in order to conserve power.
The power creep effect may seem like it is cycling through outlets. It may shut off outlets that are drawing too much power and then let other outlets have power because they weren’t drawing as much.
The outlets are also tricky about their safety features, which are
FAA required.
-You must plug straight into the outlet and do so quickly or the outlet will detect an improper connection and shut off to prevent a shock. This feature is there to prevent kids from sticking forks into the outlet and such.
-If the plug becomes misaligned (bumping it) the outlet may detect a fault and power off.
-If there is a green light the outlet power is available.
-If there is no green light, it means the outlet has detected a fault and you should unplug and try it again.
-If there is no light and you are unplugged, it means that either the system does not have enough power to spare or the safety grid system has activated and powered off the outlet.
The system is also set up to detect shorts or numerous faults.
For example, trying to plug in over and over again. If there is a red light, it means the system has detected a bad, or numerous bad, faults and has shut off. If this occurs, the only remedy is for Maintenance to reset the system.
Excessive power demands can shut off an outlet, a seat group, or even an entire grid column.
The in-seat power system also seems to employ some sort of power creep system. At the start of a flight you might have a laptop plugged into every seat, but after a while the system will start to shut off some outlets in order to conserve power.
The power creep effect may seem like it is cycling through outlets. It may shut off outlets that are drawing too much power and then let other outlets have power because they weren’t drawing as much.
The outlets are also tricky about their safety features, which are
FAA required.
-You must plug straight into the outlet and do so quickly or the outlet will detect an improper connection and shut off to prevent a shock. This feature is there to prevent kids from sticking forks into the outlet and such.
-If the plug becomes misaligned (bumping it) the outlet may detect a fault and power off.
-If there is a green light the outlet power is available.
-If there is no green light, it means the outlet has detected a fault and you should unplug and try it again.
-If there is no light and you are unplugged, it means that either the system does not have enough power to spare or the safety grid system has activated and powered off the outlet.
The system is also set up to detect shorts or numerous faults.
For example, trying to plug in over and over again. If there is a red light, it means the system has detected a bad, or numerous bad, faults and has shut off. If this occurs, the only remedy is for Maintenance to reset the system.
"Rotating" availability of electricity on 737s?
Sep 30, 2013, 9:38 pm
#1
Original Poster
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"Rotating" availability of electricity on 737s?
Heard a new one from FA on DEN-SMF this morning, and wondering if anyone can confirm or debunk.
My husband, sitting in row 21, was able to get power to his laptop prior to takeoff. But during the flight, no power. When he asked about this, one of the FAs said that the availability of electricity rotates to different seats throughout the flight, because if everyone used the electric outlets at the same time, it would be a problem.
Huh?? We've both been flying for decades, have 2.5M miles on United between us, and we have never heard anything remotely like this. Our BS detectors are buzzing away. But at the same time, we find it hard to imagine that an FA could be so disrespectful as to lie to our faces. Could this be true? Or could the FA believe it is? BTW, the power never did come on.
Inquiring minds want to know!
My husband, sitting in row 21, was able to get power to his laptop prior to takeoff. But during the flight, no power. When he asked about this, one of the FAs said that the availability of electricity rotates to different seats throughout the flight, because if everyone used the electric outlets at the same time, it would be a problem.
Huh?? We've both been flying for decades, have 2.5M miles on United between us, and we have never heard anything remotely like this. Our BS detectors are buzzing away. But at the same time, we find it hard to imagine that an FA could be so disrespectful as to lie to our faces. Could this be true? Or could the FA believe it is? BTW, the power never did come on.
Inquiring minds want to know!
Sep 30, 2013, 9:44 pm
#2
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as they should
yes, the first time you realized that has happening is very shattering. Something like a Santa Claus/Easter Bunny/Tooth Fair ... event. 
maybe but mostly likely just made it up or heard someone else say it -- go way to make the customer go away.
Most likely the circuit breaker for your seat / row had tripped.
maybe but mostly likely just made it up or heard someone else say it -- go way to make the customer go away.
Most likely the circuit breaker for your seat / row had tripped.
Sep 30, 2013, 9:49 pm
#3
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Little known facts from Cliff Clavin/UA (f/a) School of Aviation!
Last edited by LilAbner; Sep 30, 2013 at 10:08 pm
Sep 30, 2013, 10:01 pm
#6
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There's some thread in the forum that talks about the power limits and distribution onboard. The basic idea is that there is some maximum load that is provided and that when that load is reached the next thing plugged in will not get serviced.
Sep 30, 2013, 10:14 pm
#7
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This F/A was 100% correct and the reason is that Venus rotates slowly on its axis in a clockwise direction, which is referred to as a "retrograde" rotation because it is the opposite of the seven other planets. A rotation takes 243 Earth days, so a Venusian day is longer than a Venusian year. As with the other inner planets, the surface of Venus has been shaped by impact craters, tectonic activity, and volcanoes which scientists believe to be ongoing. The volcanic activity is believed to be the source of the sulfur found in the atmosphere. Venus does not have any naturally occurring satellites which would mean that a 737 flying from east to west on Venus would need to rotate is power supply to each individual seat in an opposite direction rather than if it were flying around Uranus. @:-)
Little known facts from Cliff Clavin/UA (f/a) School of Aviation!
Little known facts from Cliff Clavin/UA (f/a) School of Aviation!
Sep 30, 2013, 10:14 pm
#8
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Sep 30, 2013, 10:19 pm
#9
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n your tin-f
Sep 30, 2013, 10:20 pm
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Now I'm hopelessly confused. We have one respondent claiming definitely that it "has been proven several times," which is itself redundant, since you would think it would only have to be proven once. 
And then we have every other poster ridiculing the notion of it.
So which is it? Is there technology onboard that restricts the number of units receiving power? And are there threads "proving" as much?
And then we have every other poster ridiculing the notion of it.
So which is it? Is there technology onboard that restricts the number of units receiving power? And are there threads "proving" as much?
Sep 30, 2013, 10:26 pm
#11
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The missing information from the OP's description is if other seat sockets were also not receiving power, or if it was just the seat in question.
Once the flight deck is no longer sterile (above 10k feet) then on most aircraft types the flight deck crew need to flick the switch to direct power back to the ports. Sometimes it isn't deactivated, but recently I've seen this occur when they are activated on the ground, off once disconnected from ground power supply (APU) and during taxi and takeoff, then reactivated above 10k feet.
The way to tell in future if it is just your seat or every seat relates to a small green LED light above the socket. If this is off but every other seat socket is on, you have a problem. If all are off, then the supply needs to be flipped on for all seats.
Once the flight deck is no longer sterile (above 10k feet) then on most aircraft types the flight deck crew need to flick the switch to direct power back to the ports. Sometimes it isn't deactivated, but recently I've seen this occur when they are activated on the ground, off once disconnected from ground power supply (APU) and during taxi and takeoff, then reactivated above 10k feet.
The way to tell in future if it is just your seat or every seat relates to a small green LED light above the socket. If this is off but every other seat socket is on, you have a problem. If all are off, then the supply needs to be flipped on for all seats.
Sep 30, 2013, 10:30 pm
#12
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Now I'm hopelessly confused. We have one respondent claiming definitely that it "has been proven several times," which is itself redundant, since you would think it would only have to be proven once.
And then we have every other poster ridiculing the notion of it.
So which is it? Is there technology onboard that restricts the number of units receiving power? And are there threads "proving" as much?
And then we have every other poster ridiculing the notion of it.
So which is it? Is there technology onboard that restricts the number of units receiving power? And are there threads "proving" as much?
I'm sure that they will eventually offer an enhancement where you can swipe your credit card and obtain power throughout the flight.
Sep 30, 2013, 11:34 pm
#13
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Which is it? --- "A small green light" or a "Brown Out" that I'm supposed to be looking for???
These flight attendants, I tell ya, they're just full of all kinds of valuable poop!!!
Oct 1, 2013, 12:00 am
#14
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It's been confirmed this is true. I'm sure it saved some money. I've seen it happen. Once you are plugged in, don't unplug until you are sure you got enough power.