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"When to de-ice planes divides experts"
- From: "Stephen Irwin" <stepheni@xxxxxxxxxxxxxxxxxxxxxx>
- Date: Sat, 25 Dec 2004 21:38:54 -0600
Saturday, December 25, 2004
When to de-ice planes divides experts
Industry differences come to light after fatal Montrose crash
By Ann Imse
The Denver (CO) Rocky Mountain News
No one knows whether the pilot's decision not to de-ice caused the Nov. 28
crash in Montrose of the plane carrying NBC executive Dick Ebersol and two
of his sons.
But his choice highlights a disagreement in the air travel industry over
whether de-icing is always necessary when it's snowing. The decision is
legally up to the pilot. But the wrong choice can be deadly. Ice can distort
airflow enough to prevent an aircraft from taking off, or block the
operation of critical parts of the plane.
"The research has shown that even a grain of sand in a square centimeter on
the surface in the leading edge of an airplane can cause dramatic reduction
in life, that is, in the plane's ability to fly," said Roger Rozelle of the
Flight Safety Foundation, a private group that identifies aviation safety
problems, seeks solutions and disseminates safety information.
De-icing/anti-icing fluids cling to the plane after they are applied and
prevent precipitation from freezing for a certain period of time, depending
on weather conditions.
Rozelle insists that pilots should de-ice when it's snowing, because only
this fluid can ensure that falling snow on takeoff won't freeze to the
United, Delta and Frontier airlines all said they de-ice if it's snowing,
But the National Business Aviation Association, whose members operate
corporate jets and charters like the one that crashed in Montrose,
disagrees. Spokesman Dan Hubbard said that for charter operators, the
standard process is: "If there is freezing weather, and there is visible
precipitation accumulating on the aircraft, you de-ice."
But "the snow has to be accumulating, and it has to be sticking to the
aircraft," added Joe Hart, manager of the NBAA's service operations group.
The Federal Aviation Administration regulation says "no pilot may take off
an aircraft that has frost, ice or snow adhering to" critical surfaces such
as the wings, stabilizers and instrument systems.
The FAA says it's up to the pilot to decide whether to de-ice. "The operator
must make an observation to determine whether or not contamination has
adhered to the aircraft surfaces," the agency said in an e-mail.
Some pilots say if the snow is not "adhering," as the rule states, then
de-icing is not necessary.
The NBAA's Hart said, "If it's snowing and 35 degrees and as soon as it hits
the surface, it melts, you don't need to."
"If it's extremely light powder snow, you don't have to," he said.
But the Flight Safety Foundation's Rozelle is adamant in the other
"The accident reports speak for themselves," Rozelle said. "If you've got
snow falling, you need to put something on that wing."
In the 1990s, a number of fatal crashes convinced the industry and
regulators that planes sitting on the runway a long time after being de-iced
could lose their protection. So now, air traffic control quickly sends
planes to take off after de-icing, and the FAA publishes detailed charts
showing how long each type of de-icing fluid will protect in different
When the airlines tightened up their policies in the early 1990s, "A lot of
pilots thought if they had snow on their wings, that snow would be blown off
as they roar down the runway. And that isn't always the case," Rozelle said.
For example, sunlight might warm one wing of a plane awaiting takeoff, but
not the other, Rozelle said. Snow hitting the warmer wing might melt and
then freeze. Then more snow might cover the layer of ice. "The pilot moves
his hand on it, and the snow blows off. He says, 'It'll blow away.' "
If he has ice on just one wing, "he may be rolling down the runway to an
accident. The only way to ensure that you don't have contamination on the
aircraft is to remove it," Rozelle said.
The FAA seems to be contradictory on the subject. Its regulations leave the
de-icing decision up to the pilot. But a number of its guidelines are more
strongly worded. For example:
. An FAA advisory on de-icing small aircraft, cited by the NBAA, says ice
protection systems or procedures should be carried out whenever the
temperature is below 50 degrees and there is visible moisture present. Those
procedures don't necessarily mean de-icing, however.
. The FAA de-icing update for winter 2004-2005 has a section explaining
how long anti-icing will last if there is light snow of just 0.2 mm per
hour. That's 0.008 inches.
. Conversely, the same document advises against using de-icing fluid if
dry snow is not adhering to the aircraft. It says that if there is a
"significant" amount of dry snow, it should be removed by mechanical means
that won't cause the snow to melt.
. The FAA has approved airline plans calling for de-icing whenever it is
FAA spokesman Mike Fergus refused to provide an FAA expert to explain the
agency's advice, saying it does not allow comment on issues that may pertain
to an ongoing accident investigation.
But Arnold Scott, chief investigator in the Denver office of the National
Transportation Safety Board, said, "The FAA rules are minimums," and
airlines can choose to have tighter in-house policies. The FAA's more
strongly worded guidelines on icing have less weight than FAA regulations,
In 1996, the Department of Transportation's Office of Inspector General
recommended the FAA tighten its de-icing rules after finding six accidents
and 203 deaths caused by icing in the previous 14 years. The report found
FAA safety inspectors "disagreed over whether a light dusting of snow on the
wing constitutes ice contamination requiring a de-icing procedure."
It also said FAA inspectors were finding numerous violations of de-icing
rules, but they were not looking for patterns or seeking policy changes. As
a result, the inspector general suggested the FAA hire a de-icing expert and
develop "best practices" in de-icing to provide to air carriers.
Neither the FAA nor the inspector general's office over the course of
several days could say if the FAA adopted these recommendations. The FAA did
post an opening for the icing expert in 1996, but it is not clear whether
the position exists today.
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