Ground_Support_September2020 - 28

FUEL

If left untreated, this can lead to costly
damage to structures, potentially cost
millions of dollars or a complete writeoff in extreme cases. In normal operation,
unscheduled aircraft downtime equates
to loss of precious revenue, but also the
possible additional pay-out for passenger
compensation if flights are significantly
delayed or canceled.

Frequency of Testing for
Microbial Contamination
Accurate testing at the correct intervals
can help engineers determine the correct
testing frequencies - the objective being
to intervene at the earliest and cheapest
opportunity, well before the contamination is classified as "heavy" and requires
intensive remedial actions.
If heavy contamination levels are
reached, a full clean of a three-tank aircraft can cost in excess of $100,000 plus
three or four days of lost revenue while
the aircraft is on the ground. In total this
could be anywhere up to around $2 million.
Airlines manage the risk of contamination through periodic testing of fuel. The
interval between tests will depend on the
aircraft manufacturer's guidelines and a
risk assessment carried out by the airline.

28 GROUND SUPPORT WORLDWIDE

The risk is higher for aircraft
located in hot, humid regions where
the micro-organisms can really thrive.
In the Asia-Pacific region, for example,
the time from cleaning a fuel tank to heavy
contamination can be as little as three
months. Therefore, testing every month is
not uncommon.
In colder regions, such as Scandinavia,
the risk assessment may mean testing once
every 12 to 18 months may be sufficient.
In normal operation, aircraft may fly up
to eight times per day. At altitude, temperatures way below 20 degrees C stop microbiological growth. However, the frequency of
flights during the COVID-19 outbreak has
dropped significantly and, subsequently, the
risk of microbial contamination has greatly
increased for assets in active storage with
some fuel still in their tanks.
This has meant the interval for fuel
testing has dropped as low as once every
14 days: 24 times greater than standard
recommended testing intervals. What is
more, these aircraft are not necessarily
at their usual base location for maintenance, making it difficult and costly
to collect and send fuel samples
to laboratories. This is further
compounded by current travel
restrictions in various countries.
The practicalities of thirdparty laboratory testing during
unprecedented periods of inactivity has created a new challenge for airlines. The transport
of fuel samples not only adds
costs and logistical problems
to operations, these samples also
need to be transported in a controlled
environment so that micro-organisms
present in the sample are not compromised, leading to a false test result.

SEPTEMBER 2020

Quite simply, many
airlines are finding that
the increased frequency of
testing for aircraft across multiple airfields is not physically or financially possible, or just very difficult. Even
if fuel has been treated with biocide, the
biocide is only effective on the amount of
fuel actually in the tank, which may be
only 15 percent of full payload, contamination levels still need to be monitored to
ensure it is still working.
Immunoassay test kits, such as Fuelstat from Conidia Bioscience, offer an
onsite alternative to laboratory testing.
Now listed as an appropriate test method
for all aircraft types, immunoassays have
long been used in the medical industry to
provide quick and accurate testing to detect
specific molecules. Fuelstat uses antibodies
that bind to a specific antigen to detect its
presence and produce a measurable signal
in response to this binding that can be used
to assess fuel contamination levels.
Microbial contamination correlates to
the activity of microbial growth in the sample. The amount of antigen produced when
micro-organisms grow in the fuel is mea-

Ground_Support_September2020

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