Last night the Tatura SES Unit trained in a road rescue technique we hadn't used before. I'm writing up some notes on it now which might be useful to people, rather than trusting my notoriously sieve-like memory. The technique is referred to as "Cracking the Egg" and is an option where a car is on its roof and space is at a premium (for example, if the roof has collapsed). For the purposes of the exercise it was assumed that the vehicle is a sedan and that rear seats are unoccupied.
The first step was to remove the rear doors. Crush the door sill with the spreaders to create space to get the spreader tips in. We found last night that the base of the door was strong enough to take the pressure required to break the latch on the door. My impression was that if one ran into difficulties, it would be possible to work the spreaders around the door from the base to the latch to break it. Once the latch is broken and the door freed, it can be removed by spreading or unscrewing the hinges.
Once the rear doors have been removed on both sides, use the shears and make a relief cut through the door sill a few inches rearwards of the B-pillar (remember to peel-and-reveal the interior trim first). While this is happening, another crew member should be tasked with removing or neutralising dangers from any fuel lines, exhaust pipes or other under-vehicle fittings.
Spreaders should be equipped with chain tips and opened to their fullest extent and the chains run in a Y-pattern from each speader tip to the front and rear crossmembers. We found that it was necessary to rest the spreaders on some stabilization blocks.
Two ratchet straps should also be run from the rear to the front of the vehicle, with the ratchets hooked on at the front. From memory last night the straps and ratchets were hooked on the towing points and crossmembers. The straps should be left free in the ratchet and not tightened, and a crewmember assigned to each ratchet. When the rear is lifted, the straps can be quickly pulled through and then the ratchet engaged to tighten the straps as a safety measure.
Because the spreader chains are fairly bulky, it will be almost impossible to tighten them when they're first fitted to the car. An initial 'grab' by the spreaders will draw the chains tight and they can then be adjusted. After this has been done, the spreader operator should close the spreaders in a single non-jerky movement.
This will raise the back of the car and allow access to the casualties in the front seat.
As mentioned before, the ratchet straps should be tightened to hold the load if the spreader or chains somehow fail.
Take care not to pull the rear of the car past its tipping point: unless you've set up (say) a tirfor winch and are ready to do a controlled lowering, the falling section will cause a lot of movement in the vehicle (as in this video) and risk further injuring the casualties or trapping a crewmember. That said, a crew might be wise to put cribbing blocks on the floorpan to reduce the risk of a hand or arm being trapped.
Put together, the entire operation runs like this:
Video courtesy of Tatura SES Unit