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,
- 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:
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
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
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
- 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
- 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,
-- from Ted Strong
- the main container being very tight and the grommets
lossening without being inspected and tightened. Very common on
- new canopies with spectra (microlite) line
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.
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
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
Many other manufacturers were also contacted, but have not yet replied.
If you have corrections or additions to this article please
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.