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时间:2010-07-02 13:38来源:蓝天飞行翻译 作者:admin
曝光台 注意防骗 网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者

at the strut and ice was building quickly...Immediately
started a 180-degree right turn to depart the area; ATC
was busy on the radio at the time.... Approximately 1/2
way through turn managed to contact ATC and advise of
our situation. They cleared me down to 10,000 feet. Noted
OAT had dropped from 4 degrees C just 2-3 minutes earlier
to -7 degrees C. Completed the 180-degree turn and exited
icing conditions...with 1 inch of ice on wheel pant and
strut with windshield totally covered. Advised ATC that
we were turning...towards visible sunlight and descending
to warmer temperatures in VFR conditions, cancelled IFR,
and requested VFR fl ight following...About 2 minutes later
[satellite] weather updated to show 30 miles of mixed snow
and ice, now behind me. Ice melted completely over next
20-30 minutes. Used...terrain mapping and continuous
S-turns to maintain situational awareness regarding
terrain...Remainder of fl ight VFR with no issue.
I have prided myself on good ADM...However, I allowed
having [satellite] weather onboard to convince myself
that I had enough data to conduct the fl ight. However,
due to 5-10 minute delay in rapidly changing weather, the
[satellite] data was not current enough and is no substitute
for radar, which I did not have onboard this aircraft. My
switch back to good, positive ADM was to immediately
deviate from my clearance and start the 180-degree turn
as soon as I encountered icing conditions...We would never
have survived had we taken the ‘we can fl y through this’
approach. I don’t believe the C182 would have stayed
airborne...at the rate the ice was building...[Satellite
weather display] is a great tool to look at weather, but
it is not real-time and does come with the risk of overdependence
on the technology.
A BE58 pilot took what seemed to be reasonable prefl ight
precautions prior to taking off on a snow-covered runway
at a non-Tower airport, but lost control of the aircraft during
takeoff due to a combination of poor visibility and traction.
■ Much of the winter here there is snow, ice, or a
combination of the two covering ramps, taxiways,
and runways. However, it is relatively rare that this
combination precludes operations for most aircraft, and
I have taxied, taken off, landed many times with runway
contamination once it’s been determined that it’s safe to
do so. On the morning of departure, there had been about
1 inch of fresh snow on top of all paved surfaces that had
been cleared the day prior, which usually gives improved
(and good) traction. I drove a good portion of the ramp
area, taxiway and runway in my car to test traction and
braking and found both to be good. Brakes held fi ne
during run-up, and aircraft did not slide or give any other
indication of reduced traction during taxi into position
on the runway. During warm-up and taxi-out, a thin
layer (very thin fog with blue sky visible directly above) of
reduced visibility moved in, although ASOS continued to
report 10 miles visibility, 1,700 feet overcast. As the aircraft
accelerated during the takeoff roll, however, the layer
began visually to merge with the snow on the runway and
the snow to the side, causing me considerable diffi culty in
perceiving the runway edges at increased speed. Since no
pavement was visible, I used the marker poles that were
placed at intervals to the inside of the snow banks to keep
the aircraft centered on the runway. The combination of
fl at light and white on both runway surface and edges gave
me the impression of being well within the plowed edges
when, in fact, the aircraft had slid to the left of centerline.
The left main contacted heavier snow at the edge of the
cleared runway which quickly and uncontrollably pulled
the aircraft to the left and into the snow bank.
A contributing factor, it turns out, was that I had assumed
the entire runway had good traction from the roughly 1/3
(2,000+ feet) that I drove in my car to test it, but in fact
there was an ice layer concealed by the snow that had
persisted in the middle area of the runway...I recommend
that traction tests done with test vehicles extend over
the entire length of the runway, not just the landing and
takeoff zones, as braking action can vary signifi cantly over
the runway length.
A Monthly Safety Bulletin from
The Offi ce of the NASA
Aviation Safety Reporting
System,
P.O. Box 189,
Moffett Field, CA
94035-0189
http://asrs.arc.nasa.gov/
October 2008 Report Intake
Air Carrier/Air Taxi Pilots 2609
General Aviation Pilots 894
 
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