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
patches” between clouds.
A Monthly Safety Bulletin
from
The Office of the NASA
Aviation Safety Reporting
System,
P.O. Box 189,
Moffett Field, CA
94035-0189
October 1998 Report Intake
Air Carrier/Air Taxi Pilots 2035
General Aviation Pilots 798
Controllers 65
Cabin/Mechanics/Military/Other 168
TOTAL 3066
ASRS Recently Issued Alerts On...
http://olias.arc.nasa.gov/asrs
Number 234 December 1998
Restraint procedures during air transport of prisoners
BA-32 hydraulic pressure loss
CL-601 brake failure on landing
Cargo door failure and rapid decompression on a DA-20
TCAS II alerts attributed to a transponder on a Texas building
The Ice Cometh
This is the time of year when many pilots are gearing up for
the increased likelihood of encountering in-flight icing. Our
first reporter believed that an airplane “certified for flight
into known icing” could handle a routine IFR flight.
n [On arrival], prior to cloud penetration, all [anti-ice]
systems engaged. I continued checking the leading edges of
wings and spinners—no significant accumulation noted.
Level at 3,000 feet at about 140 knots, the airplane began to
buffet, elevator response became mushy, and it appeared the
plane was ready to stall. When I reached to add more power,
the airplane nosed over and began to turn. I went with the
turn, trading altitude for airspeed, and cycled the deicing
boots.
Ice-Bound
Loss of aircraft control due to the weight of ice and the
disruption of airflow over the wings and elevator surfaces
is only one part of the icing story. Ice accumulation can
also cause jamming or malfunction of controls and
components, as an air carrier First Officer reports:
n I was flying the aircraft on autopilot. The flight had
been normal and uneventful. During approach, ATC gave
us a descent, a turn, and a speed reduction. After
establishing the descent and turn, I extended the speed
brakes to start slowing. The speed brakes felt stiff going
past one-third extension, so I retracted and re-extended,
and they felt normal the second time. The autopilot did
not appear to roll out. I watched it closely and by 5
“Get-There-Itis”
A General Aviation pilot debated filing an IFR flight plan for
a pleasure flight in mixed VMC/IMC. The reporter even
considered canceling the flight because of the weather, but
admits that “my judgment was clouded by ‘get-there-itis’
combined with beckoning patches of blue sky.”
n After considering the options, I decided that flying VFR
would allow me the freedom to find a hole in the clouds and
get on top in clear air. As we climbed toward the blue
patches, it seemed harder and harder to find a hole large
enough to climb through. Since it looked like we only needed
to climb about another 100 feet to clear the tops, I decided that
I would plow on through. Things got worse.
At first the sun poked through occasionally, beckoning us on.
Then it started getting darker, and we picked up a trace of
rime ice. Just as I was deciding that we would have to turn
back, the engine started surging. I thought carb ice, but carb
heat didn’t help. As I was trouble-shooting the engine,
another aviation demon was sneaking up on us. It turned out
that the pitot heat was inoperative, and the pitot tube had
I declared an emergency with Approach Control. With the
increased power and resultant airspeed, and continuous
cycling of the boots, I got the plane stabilized. Approach
Control provided vectors for the ILS approach at XYZ. We
experienced no further difficulty flying the approach.
[On post-flight], there was about one-quarter inch of ice
remaining on the nose, spinners, upper portion of the tail and
other unprotected areas. I assume significant ice was shed
while descending. I have become an even more cautious flight
planner. I now know first-hand that icing conditions are
unpredictable and how severe localized icing can be—it can
quickly overpower a “known icing” aircraft.
degrees prior to heading, I was sure it was not going to roll
out. I disconnected and attempted to manually roll out. It
took considerable force to move the yoke. With more force and
about two-thirds deflection (considerably more than normal),
the controls appeared to break free. After this, the aircraft
responded and flew normally. We landed uneventfully.
Maintenance inspected, detected, and removed ice from the
control cables and pulleys.
The reporter surmised that the previous night’s rain and
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