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

RootsAir From Costa Rica, joined Feb 2005, 4179 posts, RR: 45
Posted (6 years 4 months 6 days 20 hours ago) and read 4006 times:

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
BM

A man without the knowledge of his past history,culture and origins is like a tree without roots

13 replies: All unread, jump to last

Kiwiandrew From New Zealand, joined Jun 2005, 8435 posts, RR: 14
Reply 1, posted (6 years 4 months 6 days 20 hours ago) and read 3996 times:

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

Moderation in all things ... including moderation ;-)

DIJKKIJK From France, joined Jul 2003, 1672 posts, RR: 5
Reply 2, posted (6 years 4 months 6 days 20 hours ago) and read 3996 times:

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 From , joined Dec 1969, posts, RR:
Reply 3, posted (6 years 4 months 6 days 20 hours ago) and read 3972 times:

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 From France, joined Jul 2003, 1672 posts, RR: 5
Reply 4, posted (6 years 4 months 6 days 20 hours ago) and read 3968 times:

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 From United Kingdom, joined Nov 2005, 459 posts, RR: 3
Reply 5, posted (6 years 4 months 6 days 19 hours ago) and read 3933 times:

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]

upcoming flights LHR-LAX-HNL-SFO-LHR

Hiflyer From United States of America, joined Nov 2004, 2118 posts, RR: 4
Reply 6, posted (6 years 4 months 6 days 18 hours ago) and read 3823 times:

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 From United States of America, joined Apr 2006, 58 posts, RR: 2
Reply 7, posted (6 years 4 months 6 days 18 hours ago) and read 3799 times:

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

harris

HAWK21M From India, joined Jan 2001, 31201 posts, RR: 58
Reply 8, posted (6 years 4 months 6 days 16 hours ago) and read 3630 times:

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

regds
MEL

Think of the brighter side!

Valcory From United States of America, joined Dec 2006, 88 posts, RR: 0
Reply 9, posted (6 years 4 months 6 days 5 hours ago) and read 3289 times:

That's where the external power is hooked up

N231YE From , joined Dec 1969, posts, RR:
Reply 10, posted (6 years 4 months 6 days 5 hours ago) and read 3284 times:

Quoting HarrisAir (Reply 7):

Nice picture...thank you posting that.

Valcory From United States of America, joined Dec 2006, 88 posts, RR: 0
Reply 11, posted (6 years 4 months 6 days 4 hours ago) and read 3273 times:

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 From Australia, joined Oct 2006, 61 posts, RR: 4
Reply 12, posted (6 years 4 months 6 days 3 hours ago) and read 3231 times:

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.

HAWK21M From India, joined Jan 2001, 31201 posts, RR: 58
Reply 13, posted (6 years 4 months 5 days 21 hours ago) and read 3152 times:

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

Think of the brighter side!

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