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Some big military cargo carriers carry tanks and other heavy equipment and I am not sure if they have some kind of special locks or tie-downs in the cargo space to manage those heavy loads.

How are these very heavy loads secured?

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  • $\begingroup$ You mean tiedowns? $\endgroup$ – ratchet freak Oct 8 '15 at 12:07
  • $\begingroup$ i guess tiedowns are for the complete aircrafts but do we use the same inside the cargo as well as to tie the tanks etc? $\endgroup$ – NitinG Oct 8 '15 at 12:12
  • $\begingroup$ @NitinG - I've tweaked the question a bit, I hope this retains the flavor of what you were asking, while clarifying it. $\endgroup$ – FreeMan Oct 8 '15 at 16:13
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    $\begingroup$ Not always well enough, unfortunately. ntsb.gov/news/press-releases/Pages/20150714b.aspx $\endgroup$ – Fred Larson Oct 8 '15 at 16:53
  • $\begingroup$ ^ Accompanying video of the crash: youtube.com/watch?v=-MB9JDBe4wA $\endgroup$ – Danny Beckett Oct 8 '15 at 23:00
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The cargo in a military aircraft are secured in the cargo hold using chains, straps etc. connected to stowage tie-down devices, which go into tie-down rings . The following image shows a M1 Abrams tank secured in C-17 Globemaster III using tie-down devices.

M1 Abrams tiedown

USAF uses three different types of devices to secure cargo in aircraft, which vary in their load capacity:

  • MB-1 tie-down device with 10,000 lb rated capacity.

  • MB-2 tie-down device with 25,000 lb rated capacity.

  • CGU-1/B tie-down device with 5,000-pound rated capacity

The MB-1 and MB-2 are similar in their form and function, with the only difference being their load capacity.This image shows a close-up of the MB-1 and MB-2 tie-down devices:

C-17 tie-down devices

"C-17 Globemaster III no. 5139 stowage tiedown devices" by BrokenSphere - Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons.

The hook goes into the tie-down ring, while on the other end, straps or chains (from the cargo) go.

The CGU-1/B is a 20-foot nylon web strap with two metal hooks at both ends. While one hook is stationary, the other hook has a ratchet device and can be moved and tightens the device when it is being used.

CGU-1/B

Note: Apparently, Military designation system refers to MB-1 and MB-2 as CGU-3/E and CGU-4/E respectively.

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  • $\begingroup$ In the Abrams picture it looks like one of the chains has a lot of slack. Do you know whats up with that? $\endgroup$ – David Grinberg Oct 8 '15 at 15:35
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    $\begingroup$ I think what you're looking at is the slack unused length of the chain used in the tie-down. It's wrapped over the taut span above it which is the same chain. $\endgroup$ – KeithS Oct 8 '15 at 15:37
  • $\begingroup$ In other words, they use the same things to tie the equipment down in the plane as they would on a ground based transport. They probably just throw an extra one or two in because a shifting load on a truck is an annoyance while in a plane, a shifting load can be fatal. $\endgroup$ – FreeMan Oct 8 '15 at 16:22
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    $\begingroup$ @FreeMan: Load shifts in a truck can be much more than an annoyance, and can even be fatal as well. Here's one: wyandottedaily.com/… $\endgroup$ – Fred Larson Oct 8 '15 at 18:18
  • $\begingroup$ Load shifts are problematic no matter the mode -- a shifted heavy load on a flatcar can derail a train or worse yet, wipe out a through-bridge structure altogether; shifted loads can also cause stability hazards in marine transportation. $\endgroup$ – UnrecognizedFallingObject Oct 9 '15 at 1:34

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