rootsair
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What Exactly Is This On The Front Of The A/C?

Sat Jan 20, 2007 8:06 pm

hi folks,

I have a question to ask. As you can see something is plugged in front of the a/c. I encircled it in red and have always wondered what this is for?
Could anyone help. Thanks
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kiwiandrew

RE: What Exactly Is This On The Front Of The A/C?

Sat Jan 20, 2007 8:09 pm

I would guess it is either :

1 / connection from ground power unit to supply electricity so that the a/c doesn't need to burn fuel using the APU

or

2 / a communication feed from the ground - but it looks a bit heavy duty for that so I will stick with my first guess until somebody more knowledgeable shoots me down  Smile
 
DIJKKIJK
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RE: What Exactly Is This On The Front Of The A/C?

Sat Jan 20, 2007 8:09 pm

I think it is something that enables the ground crews to communicate with the pilots. I've seen headphones hanging from those.

I'm really not sure tho, I hope some expert will clarify
Never argue with idiots. They will bring you down to their level, and beat you with experience.
 
Magyarorszag
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RE: What Exactly Is This On The Front Of The A/C?

Sat Jan 20, 2007 8:17 pm

Quoting Kiwiandrew (Reply 1):
1 / connection from ground power unit to supply electricity so that the a/c doesn't need to burn fuel using the APU

I would say that too. The big yellow tube is there for that purpose too and provides air IIRC.
 
DIJKKIJK
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RE: What Exactly Is This On The Front Of The A/C?

Sat Jan 20, 2007 8:19 pm

I think this thread is better suited to the Tech/Ops.
Never argue with idiots. They will bring you down to their level, and beat you with experience.
 
LGWspeedbird
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RE: What Exactly Is This On The Front Of The A/C?

Sat Jan 20, 2007 8:31 pm

Its the ground power unit! Once the aircraft comes on stand and shuts down the loaders plug it in!

Ive had it before that the captain has not shut the engines down because he has not been plugged in!

Have managed to find a pic



If you look by the nose wheel of the a/c you can see a yellow box connected to a white zig zag thing (sorry for the technical terms) there is a heavy duty cable that gets pluged into the aicraft.

BTW the pic is of a titan airways 75 when it was subbing for GB airways last summer

[Edited 2007-01-20 12:39:30]
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hiflyer
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RE: What Exactly Is This On The Front Of The A/C?

Sat Jan 20, 2007 9:54 pm

That is the 6 prong female end of the ground power cable that is used to power the aircraft when the apu is not operating. Current widebodies require 2 if they are going to keep galley power going and I believe the 380 will need 3. The yellow hose you see off the Captains side is the ground air conditioning...again wide bodies require 2 and the 380 even more! Carriers prefer using ground equipment to supply aircraft if the turn time allows it as it is cheaper than using the apu factoring in fuel costs as well as overhaul costs on the apu after so many hours of use. Most newer airports take that into account and install the needed units on the jetways using city power rather than the older way of having actual ground equipment cluttering the gate running on gasoline or diesel.
 
harrisair
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RE: What Exactly Is This On The Front Of The A/C?

Sat Jan 20, 2007 10:05 pm

Big version: Width: 1600 Height: 1200 File size: 718kb


harris
 
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HAWK21M
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RE: What Exactly Is This On The Front Of The A/C?

Sun Jan 21, 2007 12:23 am

Ground power unit to supply 115vAC 400Hz to the Aircraft on Ground with APU shutdown.

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Valcory
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RE: What Exactly Is This On The Front Of The A/C?

Sun Jan 21, 2007 11:13 am

That's where the external power is hooked up
 
N231YE
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RE: What Exactly Is This On The Front Of The A/C?

Sun Jan 21, 2007 11:21 am

Quoting HarrisAir (Reply 7):

Nice picture...thank you posting that.
 
Valcory
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RE: What Exactly Is This On The Front Of The A/C?

Sun Jan 21, 2007 11:42 am

Quoting DIJKKIJK (Reply 2):
I think it is something that enables the ground crews to communicate with the pilots. I've seen headphones hanging from those.

You can hooked up a headset there to talk to the flight crew in the cockpit
 
TheJoe
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RE: What Exactly Is This On The Front Of The A/C?

Sun Jan 21, 2007 12:39 pm

Quoting HAWK21M (Reply 8):
Ground power unit to supply 115vAC 400Hz to the Aircraft on Ground with APU shutdown.

Exactly. If you have a look at the plug itself, it has four heavy duty prongs that provide the 115V 400Hz three phase power to the aircraft. There are also two smaller prongs that are part of the aircraft's 28V DC system as well. The 28V DC prongs are shorter than the four AC prongs for safety reasons. The relay that activates the ground power will not function unless the 28V DC prongs are fully engaged in the plug. That means that the AC prongs will also have to be fully engaged as well. This stops ground power from being activated from the flight deck with the plug only partially engaged preventing shorts and possible injury or death to ground staff who are connecting the aircraft up! This can make it quite difficult on the 737 if the battery is flat. No 28V DC means no ground power! Time for a battery change before power can be applied.

On the 737, the access panel that houses the ground power socket also has two headset jacks. One is the flight interphone used to speak to the crew on a turnaround or provide a method of communication from the tug to the flight deck during towing operations. The other is the service interphone used in conjunction with the other interphone locations on the aircraft for maintenance purposes. In the access panel, there are also two lights. On our 737's, one white light shines when ground power is NOT in use so we know it is safe to disconnect. The other light is red. On when the brakes are set, off when they're not. Handy for a turnaround so you can visually confirm the brakes have been released before commencing a pushback.
 
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HAWK21M
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RE: What Exactly Is This On The Front Of The A/C?

Sun Jan 21, 2007 7:03 pm

Quoting TheJoe (Reply 12):
There are also two smaller prongs that are part of the aircraft's 28V DC system as well

The E & F Pins are used to disconnect supply if inadvertantly the Plug is pulled with Generator on GPU not switched off.It eliminates Arcing.
regds
MEL
I may not win often, but I damn well never lose!!! ;)

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