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Line Snags on Grommets

by Jan Meyer

A malfunction mode of suspension lines snagging on grommets has a higher probability of occurance on late 1990's equipment than earlier equipment. Factors that contribute to this include:
  • small diameter suspension lines,
  • deployment when a jumper is not face to Earth and
  • assembly-line packing techniques that overlook the placement of lines in the pack tray.

These contributing factors are on the increase because

  • more canopy manufacturers use new materials for suspension lines,
  • more jumpers participate in freefly, headdown and board jumps, and
  • many jumpers use packers.

These malfunctions can be extremely dangerous. When a suspension line of a main canopy snags a grommet:

  • The main is most certain to malfunction.
  • The main usually will not separate from the jumper, even when a cutaway has been executed.
  • The trailing main canopy has a high probability of entanglement with a reserve canopy.

Two fatalities, that occured early in 2000, illustrate two different malfunction modes of a suspension line snagging a grommet:

  • Line hung up on grommet Reflex: a suspension line snagged the grommet on the top flap
    The red line represents the routing of the snagged line. The line was twisted many times, as denoted by the crossing red lines. A possibility of an improperly seated grommet and thin Vectran lines on the main (Safire) may have increased the likelihood of this malfunction. The malfunction occured on the fifth jump on the brand new rig.
    See also Fliteline's Service Bulltin
  • Javelin: a suspension line snagged the grommet on a tongue type main closing loop
    The suspension line was twisted around the grommet.
    See also SunPath's Service Bulletin or SunPath's Service Bulletin-Sun Path's site

Before these fatalities occured, there were several reports of these malfunctions that have been non-fatal. Eight documented incidents are listed:

  • Racer: In the early 1990's, JumpShack recieved a report of a line snagging the grommet on a tongue type main closing loop
  • Vector, Talon and Mirage: In 1998, the Australian Parachute Federation reported of line snagging the grommet on a tongue type main closing loop in this Service bulletin.
  • Naro: In the late 1990's, a Southern California jumper had a suspension line snagged by the grommet on a tongue type main closing loop on TWO separate occasions
  • Strong Enterprises System Two: (Two different types of rigs) We changed to installing the Type 3 tape mentioned below. I percieve the problem coming from 2 areas,
    1. the main container being very tight and the grommets lossening without being inspected and tightened. Very common on student gear.
    2. new canopies with spectra (microlite) line
    -- from Ted Strong

The malfunction may happen on any container system that has a tongue type type main closing loop. Some containers are still manufactured with the tongue type main closing loop. Some have never been manufactured this way or only for a short time period. Still other containers have protective materials to prevent a line snag.

  • Quasar: The webbing is attached to the base of the main container and reserve. The grommet on the webbing has Type 3 tape over it to provide a slit for the closing loop. The grommets are not exposed to the canopy bag or lines. -- from Ted Strong
  • Infinity: Containers produced before Jan. 1999 did have a tab for the main closing loop. Current production does not have the tongue type closing loop. -- from Kelly Farrington
  • Racer: For a short period of time in the early 90's (about 3 months) we used a tongue (webbing strip w/grommet) as a main closing loop anchor. We were opposed to it at the time because of the obvious potential. However, the sub-contractor who manufactured the Racer for us at that time persuaded us to change to the tongue design for ease of manufacturing. We let ourselves get talked into it despite our better judgment. Within about 3 months we had a report of a steering line entangling with the tongue. We immediately returned to the original design of a tray mounted flat retainer which we use to this day with no reported problems. -- from John Sherman
  • Vector: The Vector III's main loop originates from the bottom main flap, so that system does not exhibit this problem. The Vector II however uses a loop retainer (or tongue if you prefer) that originates from the base of the divider flap. The Vector I started this series using the same loop retainer, first built in 1981. We stopped building Vector I's during mid 1986 when the Vector II was introduced. We still continue to build a few Vector II's, usually for foreign military contracts. We probably have over 25,000 Vector I and II systems use today around the world. Tens of millions of jumps have been made on loop retainers of this type.

    Regarding the APF product service bulletin: That is a righteous PSB. Most Vectors have that 'tongue' facing in the right direction. Relative Workshop has just issued a Product Safety Bulletin that calls for the removal of this loop retainer. This PSB #20000302 explains the reasons we have done so. PSB #20000302 has been recinded. -- from TK Donle

  • Wings: Closing loop retainer is sewn down to the wall between the reserve container and main container. It has been that way since the beginning of our manufacturing, 1998. -- from Henri Pohjolainen
  • Dolphin: Our main closing loop is held by a tongue-type retainer which is attached at the junction between the main and reserve containers. When we started production, the grommet was on the underside of the tab because it seemed to lay a little better when packing. About eight months later we received a suggestion that the grommet would be less likely to snag a suspension line if it were on the top, and since that sounded pretty logical, we started installing the tab with the grommet up. About two years ago, after hearing of the incident reported by the APF, I made what I call a preemptive design change. I added a piece of tape which covers half the grommet, making it virtually impossible for anything to catch on it, and this is the design we are still using. We install the tab with the half-shielded grommet on the upper side, and of course the washer on the lower side is completely covered. -- from Mike Furry
  • Other manufacturers did not provide feedback in this area.

Grommet seating may have played a role in any or all of these incidents. All manufacturers state the a *fingernail* test is used to check for proper seating. If you can get your fingernail under the grommet, then it is not seated properly. (Author's note: I thought a thickness gauge was used, since the clearance is so small.)

Whether the grommet washer faces the bag or faces away from the bag does not appear to matter. When the grommet is properly seated boths sides of the grommet are snug with the material. On loose grommets, a line can snag on both sides of the grommet.

In addition to a suspension line snagging a grommet on the tongue type closing loop, a line may half-hitch around the tongue. This is the reason Relative Workshop issued PSB #20000302, after the fatality mentioned above that happened on a Javelin container.

Precautions that each jumper may take to reduce the probabilty of these malfunction modes include:

  • Check grommet seating during EVERY packing. Grommets loosen with age.
  • Ensure proper placement of suspension lines in container.
  • Deploy face to Earth.
  • Remove a tongue type closing loop.

See also the PIA Technical Bulletin TB-301

Manufacturers that contributed to the information in this article include:

Their help and unselfish giving of their time to answer a long list of questions is very much appreciated by myself and anyone that learns to reduce the probability of occurance of these very dangerous malfunction modes.

Many other manufacturers were also contacted, but have not yet replied.

If you have corrections or additions to this article please email them.

Sport Parachutist's Safety Journal
©Copyright 2000 by Jan Meyer.

Dedicated to enhancing sport parachuting safety by disseminating information about equipment, environments and human factors.

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