767 power - AA reactivated all 762 ports; Main cabin 763 by "end of 2011" (not quite)
Nov 15, 2012, 7:53 pm
#646
Join Date: Sep 2011
Location: Philadelphia
Programs: AA lifetime plat 2.5 million
Posts: 298
<moderator has removed quoted post with circular link>
Last month, I flew ORD/LHR/ORD both ways on 767's in Y. 1 way on; 1 way not. Asked the fa and was told "It seems to be hit or miss."
Last month, I flew ORD/LHR/ORD both ways on 767's in Y. 1 way on; 1 way not. Asked the fa and was told "It seems to be hit or miss."
Last edited by JY1024; Nov 15, 2012 at 9:41 pm Reason: moderator has removed quoted post with circular link
Mar 6, 2013, 4:12 pm
#647
Original Member
Join Date: May 1998
Location: NYC
Programs: AA 2MM, Bonvoy LTT, Hilton Diamond
Posts: 14,638
Took 3 763 flights in the past 6 months. Power was activated on all three flights in MCE.
Currently on SFO-JFK 763. Power active in main cabin as well. Seems like you'll have a higher chance of getting power in MCE vs main cabin. Last week, power was in in MCE but not main cabin.
Currently on SFO-JFK 763. Power active in main cabin as well. Seems like you'll have a higher chance of getting power in MCE vs main cabin. Last week, power was in in MCE but not main cabin.
Last edited by seawolf; Mar 7, 2013 at 3:56 pm
Mar 18, 2013, 12:20 pm
#648
Join Date: Mar 2013
Posts: 1
any news on the 767-300 international flights?
its a shame they are not capable of fixing this in an almost 2 years time.
its a shame they are not capable of fixing this in an almost 2 years time.
Mar 18, 2013, 12:45 pm
#649
FlyerTalk Evangelist
Join Date: May 2002
Location: NYC, USA
Programs: AA EXP 3MM, Lifetime Platinum, Marriott Titanium, HH Gold
Posts: 10,967
Wirelessly posted (Apple iPhone: Mozilla/5.0 (iPhone; CPU iPhone OS 6_1_2 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10B146 Safari/8536.25)
767-300 has active powerports in NGBC on all birds. The solution is always to fly upgraded or buy a premium class ticket.
767-300 has active powerports in NGBC on all birds. The solution is always to fly upgraded or buy a premium class ticket.
Mar 18, 2013, 5:15 pm
#650
Moderator: American AAdvantage
Join Date: May 2000
Location: NorCal - SMF area
Programs: AA LT Plat; HH LT Diamond, Maître-plongeur des Muccis
Posts: 62,948
A good explanation, IMO, but AFAIK the primary system on the 767 (and 777, 757, etc. - 767 system is iirc identical to the 757 system) is the usual 3-phase, 4-wire 400 Hz, 115/200 Volt system (with neutral actually being the airframe, from a 12,000 RPM oil-cooled alternator); then it gets rectified and stepped down to the 28 VDC (airframe is negative polarity) for other systems, with further changes as needed down the line (e.g. 15 VDC for in-seat power in the 763).
Wires crossed...
(actually, a good chuckle.)
Wires crossed...
(actually, a good chuckle.)I hate to introduce facts here but....
You are correct - as far as everyone here has been told the reason for the suspension of power ports on some aircraft was related to a safety issue.
As far as you statement that DC power somehow looses more current over long distances I think you got your wires crossed (get it? waka waka). Without getting in to too much detail, because of what's called the 'skin effect' AC power will have more resistance natively than DC current, which leads to both more heat and more power loss. The reason DC current isn't used in capacity environments (like the power lines over your home or the distribution architecture at a big power site like a data center or a factory) relates to the expense in transforming DC power to suitably high enough voltage for transmission. When high current is required at a site you are much better off stepping up to a high voltage to reduce current and, therefore, conductor size, for transmission (thanks China!) and it is tons easier to do this with AC power.
There are exceptions to this and if you are looking at a large scale implementation with lots of transformers and lots of super high voltage transmission AC current will start to have an edge again but in the context of the low voltage scope of an airplane's tiny power system it is quite untrue to say that DC looses current compared to an AC implementation.
Also keep in mind that the generators on the airplane operate off of DC power. Almost all of the little motors (AC units, doors, etc.) are DC motors. Almost all avionics are DC powered. So since the airplane only has DC power available when in the air any AC power has to come from rectifiers which themselves generate heat and are associated with overhead. So even if AA installed a couple big rectifiers and distributed AC to each seat, they would be losing the overhead power associated with converting DC to AC and then again lose power because of that pesky 'skin effect'.
So there's at least two ways that DC power is more efficient and of course that doesn't take in to account the fact that all that lost power turns directly in to heat, which they then have to pay to cool to keep customers comfy.
You are correct - as far as everyone here has been told the reason for the suspension of power ports on some aircraft was related to a safety issue.
As far as you statement that DC power somehow looses more current over long distances I think you got your wires crossed (get it? waka waka). Without getting in to too much detail, because of what's called the 'skin effect' AC power will have more resistance natively than DC current, which leads to both more heat and more power loss. The reason DC current isn't used in capacity environments (like the power lines over your home or the distribution architecture at a big power site like a data center or a factory) relates to the expense in transforming DC power to suitably high enough voltage for transmission. When high current is required at a site you are much better off stepping up to a high voltage to reduce current and, therefore, conductor size, for transmission (thanks China!) and it is tons easier to do this with AC power.
There are exceptions to this and if you are looking at a large scale implementation with lots of transformers and lots of super high voltage transmission AC current will start to have an edge again but in the context of the low voltage scope of an airplane's tiny power system it is quite untrue to say that DC looses current compared to an AC implementation.
Also keep in mind that the generators on the airplane operate off of DC power. Almost all of the little motors (AC units, doors, etc.) are DC motors. Almost all avionics are DC powered. So since the airplane only has DC power available when in the air any AC power has to come from rectifiers which themselves generate heat and are associated with overhead. So even if AA installed a couple big rectifiers and distributed AC to each seat, they would be losing the overhead power associated with converting DC to AC and then again lose power because of that pesky 'skin effect'.
So there's at least two ways that DC power is more efficient and of course that doesn't take in to account the fact that all that lost power turns directly in to heat, which they then have to pay to cool to keep customers comfy.
Dec 7, 2014, 7:51 am
#651
Join Date: Jan 2010
Location: Fredericksburg, VA
Programs: American AAdvantage Platinum Pro
Posts: 76
Is there a reason why the power ports on a 737-800 would not be turned on? I asked the flight attendant and she said there will be no power ports today.
Dec 7, 2014, 9:04 pm
#652
Join Date: Jun 2006
Location: SFO/OAK
Programs: AA EXP 3.4MM, BAEC, UAMP, Skyteam (<10k) HH Gold, IHG Plat, Hertz Gold, GE/TSA TT
Posts: 2,723
I've had a lot of problem with power ports over the past 2-3 years, but not on a 737. It was probably (just another) deferred maintenance issue.
Dec 7, 2014, 9:17 pm
#653
Moderator: American AAdvantage
Join Date: May 2000
Location: NorCal - SMF area
Programs: AA LT Plat; HH LT Diamond, Maître-plongeur des Muccis
Posts: 62,948
A reminder there is a master power thread, and this thread is about 763 power issues.
Thanks for keeping threads on topic.
/Moderator
Thanks for keeping threads on topic.
/Moderator