Another important reason for excluding certain
vulnerable demographics such as the disabled, children
and elderly or obese passengers is the risk involved in
conducting the tests.
“There’s a considerable risk factor whenever you ask
the general public to do an evacuation,” says Marisa
Garcia, an aviation industry analyst who formerly
worked in aircraft seat manufacturing. “There’s always
the possibility of somebody hurting themselves on the
way out. This is one of the reasons why these types of
tests don’t happen very often.”
KNEE BRACES & FAT SUITS
Safety concerns around evacuation tests have long been
recognized by the industry. Before the launch of the
A380, Airbus at first refused to conduct a full evacuation
test because of concerns that any accidents incurred
during the testing could be turned to rival Boeing’s
commercial advantage.
The risk in evacuation tests comes from the need to
instil a sense of urgency in the participants, so that the
simulated evacuation can as closely as possible match the
real thing. The researchers behind the CAMI tests
“manipulated motivation by providing a monetary
incentive,” says David Weed, team coordinator of CAMI’s
Cabin Safety Research Team.
This approach was pioneered at Cranfield University
in the UK during the 1990s by passenger safety expert
Professor Helen Muir. Garcia has seen video footage of
one of the Cranfield tests where the incentive was the
offer of a cash reward for a proportion of the passengers
who evacuated first. She says the footage shows clearly
the rationale behind excluding vulnerable demographics
from the studies. “You had people climbing over each
other to get out of the cabin first,” she says.
But according to Coleman there are different ways to
take account of slower people without exposing them to
risk themselves. “You can limit the mobility of healthy
people,” he says. “You can put a knee brace on a healthy
person to play the part of a disabled person. Or you could
put someone in a bodysuit that mimics the dimensions of
an obese person.”
While “safety and ethical reasons” played a part in
their thinking, the main reason for excluding these more
marginal demographics from the CAMI study was to
avoid polluting the results with extra variables. “We’re
really trying to isolate seat pitch and width and see if
they are the underlying safety issue,” Weed says. “If we
SIMULATORS
AEROSPACETESTINGINTERNATIONAL.COM // MARCH 2020 85
IS CRASH TESTING THE BEST
WAY TO ASSESS SEAT SAFETY?
Dynamic crash testing of seating can also reveal important
data about passenger safety. However, industry analyst
Marissa Garcia says the crash test dummies used in such
tests are inaccurate.
“We use crash test dummies based on the automotive
standard, which is not reflective of the body mass index
of the general population today, which we know has
increased since these metrics were first created back in
the 1970s.”
The reason why these standards have not been updated
may reflect a reluctance within the industry to face the
financial and logistical consequences of a negative result,
she says. “If the dynamic crash testing shows that it’s
unsafe for people of average size today to be thrust in
their seats at 16 g then they need to change the cabin
regardless of whether or not those people can evacuate
in time.”
“The researchers behind
the tests manipulated
motivation by providing
a monetary incentive”
3
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