Freighters are Equipped with a 9G bulkhead or 9G net.
Why 9G,not more.How was it decided that 9G resistant would be adequate.
Also the 9G bulkhead needs to be attached to reinforced Floor boards.Are there any other methods of Attachment.
BTW nice photoid number
A/c train From United Kingdom, joined Jun 2001, 501 posts, RR: 4
Reply 2, posted (8 years 4 months 3 weeks 2 days 20 hours ago) and read 4591 times:
Hawk, maybe you havn't worked heavy maintenance and have not seen barrel nuts in floor structure, or have not locked a seat to a seat track floor beam. Must admit rather surprsing, I guess it all depends on what maintenance background you have. There are indeed holes for floor bushings in the composite floor boards which may make it seem like they are attached to just the floor boards.
Ilikeyyc From United States of America, joined Dec 2003, 1373 posts, RR: 20
Reply 3, posted (8 years 4 months 3 weeks 2 days 18 hours ago) and read 4566 times:
The aft wall in the CRJ that separates the cabin from the aft cargo is also known as the 9G wall. But since I'm new to Mx, I am curious as to what 9G means and how it got this name. Before this thread, I thought it was a term used only on the CRJ.
Unless I'm completely off my rocker, it simply means the barrier is meant to withstand 9 G's (IE 9x the force of gravity)
And for Hawk, I believe they are rated at 9G's and not more simply because if you are experiencing over 9-G's you would be having much more serious problems than cargo passing through the net/wall (non-military aircraft of course)... Your guess is as good as mine as to why they chose the figure of 9
474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 7, posted (8 years 4 months 3 weeks 2 days 16 hours ago) and read 4527 times:
Quoting Ilikeyyc (Reply 6): That is what I inferred from Hawk's post. What had me puzzled is that 9g's of lets say a passenger's bag produces a different force than 9g's of an entire bin filled with bags. So 9g's of what?
If an overhead bin has a maximum capacity, 60 pounds. It would have to be built to withstand a 540 pound load in the forward direction. 9 X 60 = 540.
Lotsamiles From United States of America, joined May 2005, 323 posts, RR: 0
Reply 11, posted (8 years 4 months 2 weeks 6 days 16 hours ago) and read 4378 times:
Quoting HAWK21M (Thread starter): Also the 9G bulkhead needs to be attached to reinforced Floor boards.Are there any other methods of Attachment.
The 9G barrier is typically attached to a shear plate mounted to the floor beams that carries the load out to the fuselage skin. At the top there are fittings that carry loads out to doublers either inside or outside the skin, or sometimes stringers. The floorbeams are not able to take much in the way of fore/aft loads.
The cargo system restraints are rated for 3G so the 9G is intended to protect the crew in a very hard landing when the cargo system fails and everything moves forward into the barrier.
113312 From United States of America, joined Apr 2005, 572 posts, RR: 1
Reply 16, posted (7 years 2 months 2 weeks 3 days 21 hours ago) and read 4063 times:
I believe that 9G was an arbitrary value that the FAA and other certifying authorities applied many decades ago for stress on most attach points including seats and cargo restraints. However, experience has proven this number to be inadequate and now most seat structures and mounts are designed for greater crash-worthiness. The official standard for cargo barriers has not changed. A net at the forward end of a cargo compartment is a secondary restrain as most cargo is loaded into containers and those are locked to the floor with locks that have greater strength. Also, many all cargo aircraft use a rigid forward cargo barrier rather than the net systems.