Bernard...info

[jackpilot]

What the **** is that heavy gizmo (747)

https://www.ebay.com/itm/Boeing-747-400-Counter-Balance-Airborne-Avionics-Assembly-258T1190-8-Seviceable/372655695954?epid=8029147784&hash=item56c402a852:g:g7QAAOSwFeNcZ2ur&frcectupt=true

[Trevor Hale]

I think it makes to door Easy to open, it Counteracts the weight of the door, so the flight attendant can open it easily.
That's my guess anyway.

[blueskydriver]

I need one of these to get out of bed each day! Just way too tired!! 

John

[Garys]

These are used on doors that open up vertically to the airframe, such as bulk cargo doors etc.( pax doors 767 as well )  Doors that open up parallel aren't affected by gravity so don't  need these big heavy items.

[FredK]

Looks like home garage door technology.......a simple torsion spring with an adjustable tension feature added.

Fred K