Numerous helicopter crashes have been attributed to flight deck cargo nets fouling the landing skids or wheels of helicopters. Who still uses this stuff? Any other stories or near misses out there?
We have one O/B in the Gulf Of Mexico. We never use it. During transit we have it ready certain operators require then net in areas of the world. (south Africa) is one i know of.
This is a military training outline for Vertical Replenishment. They use cargo nets, cargotainers and pallets. There are quite a few warnings in the article about loose stuff laying around the landing pad area.
CLEARING THE VERTREP AREA
9-13. Once the load is released and the helicopter has departed, cargo handlers will prepare the load for distribution to the users or relocate it clear of the landing area.
l Unloading the Cargo. Nets, beckets, and cargo wraparound straps shall never be cut.
n Assigned men open the net and cut any banding or strapping on the load. Cargo handlers, who have been standing by clear of the VERTREP area, move in, pick up a portion of the cargo, and leave the VERTREP area. The last ones remove the net and loose debris from the VERTREP area, and place them in a staging area. The nets are folded for later return to the helicopter.
[QUOTE=billslugg;42584]This is a military training outline for Vertical Replenishment. They use cargo nets, cargotainers and pallets. There are quite a few warnings in the article about loose stuff laying around the landing pad area.
CLEARING THE VERTREP AREA
9-13. Once the load is released and the helicopter has departed, cargo handlers will prepare the load for distribution to the users or relocate it clear of the landing area.
l Unloading the Cargo. Nets, beckets, and cargo wraparound straps shall never be cut.
n Assigned men open the net and cut any banding or strapping on the load. Cargo handlers, who have been standing by clear of the VERTREP area, move in, pick up a portion of the cargo, and leave the VERTREP area. The last ones remove the net and loose debris from the VERTREP area, and place them in a staging area. The nets are folded for later return to the helicopter.[/QUOTE]
Yes but the Navy uses cargo nets to actually lift cargo, not so offshore. The nets we are talking about are ment to keep helicopters from skidding. They are required by CAP-437 which states:
9.1 Safety nets for personnel protection should be installed around the landing area except where adequate structural protection against falls exists. The netting used should be of a flexible nature and be manufactured from non-flammable material, with the inboard edge fastened level with, or just below, the edge of the helicopter landing deck. The net itself should extend 1.5 metres in the horizontal plane and be arranged so that the outboard edge is slightly above the level of the landing area, but by not more than 0.25 metres, so that it has an upward and outward slope of at least 10°. The net should be strong enough to withstand and contain, without damage, a 100 kg weight being dropped from a height of 1 metre.
9.2 A safety net designed to meet these criteria should not act as a trampoline giving a ‘bounce’ effect. Where lateral or longitudinal centre bars are provided to strengthen the net structure they should be arranged and constructed to avoid causing serious injury to persons falling on to them. The ideal design should produce a ‘hammock’ effect which should securely contain a body falling, rolling or jumping into it, without serious injury. When considering the securing of the net to the structure and the materials used, care should be taken that each segment will meet adequacy of purpose considerations. Polypropylene deteriorates over time; various wire meshes have been shown to be suitable if properly installed.
The reason that we don’t use them in the gulf is that we (American’s) have common sense and don’t follow the rules, like this one, that are dangerous. We had a British aviation inspector come out to our rig once raising hell and asking why we didn’t have a net up. I showed him the picture Rob posted and he didn’t care so we installed the stupid thing… the pilots refused to land!
Most former british colonies have common sense too… but they are too scared of the queen to raise their hand, so they follow the rules to the tea and have accidents.
I you have a good non-skid, they’re not required. CAP-437 actually states the acceptable deck friction coefficient to not use the net.
The photo Rob used on the Cargo Net blog post is of the Discoverer 534 while drilling off the coast of India. No one was injured in the crash but we did find shards from the rotor blade embedded in the steel legs of the derrick. CAP-437 has since been amended with a notation that cargo nets are not to be used for landing helicopters with skids but the dam things are too heavy to switch out for every new chopper.
My thought is if the deck is rolling enough to be a concern for wheeled helicopters then they shouldn’t land. Otherwise, if it’s an emergency I can get a gang of roustabouts and seamen to get the net in place quick.
[QUOTE=john;42608]The photo Rob used on the Cargo Net blog post is of the Discoverer 534 while drilling off the coast of India. No one was injured in the crash but we did find shards from the rotor blade embedded in the steel legs of the derrick. CAP-437 has since been amended with a notation that cargo nets are not to be used for landing helicopters with skids but the dam things are too heavy to switch out for every new chopper.
My thought is if the deck is rolling enough to be a concern for wheeled helicopters then they shouldn’t land. Otherwise, if it’s an emergency I can get a gang of roustabouts and seamen to get the net in place quick.[/QUOTE]
It will have to be a gang for sure, to be quick. I’m looking at a tie down every meter, around a 21 meter circumference, with some type of ratchet strap. This boat was just delivered and that’s the only reason I think it’s in place.