there have only been scattered flurries of weather-related ASRS reports
recently, the forecast is for increasing intensity over the next few
months. On the brighter side, ASRS Analysts do see a chance for significant
clearing of embedded gray cells and foggy memories provided there
is heavy participation in a review of cold weather operations and
procedures. A high absorption rate of the towering accumulation of
lessons learned could prevent an avalanche of reports at ASRS.
"chilling" statement reflects the gravity of the situation
encountered by an instructor and student in an ice-encumbered Cessna
172. Knowing the limitations of one's aircraft and having a respect
for the forces of nature are two universal lessons learned by the
instructor who submitted this report.
[Cessna 172] began to accumulate light rime ice in cruise at 10,000
feet... Icing became increasingly heavier until...we were having
difficulty maintaining altitude. Departure [said] he needed us to
maintain 10,000 feet. I told him we were picking up ice and requested
vectors [to the] ILS Runway 35 at XXX... We checked in with the
Tower [and we were] cleared to land. Icing was moderate at that
point. We had full throttle at 70 KIAS and [we were] descending
400 feet per minute. We were unable to maintain approach minimums,
and at one point Tower said, "You probably know this, but I'm
getting an altitude alert..." We briefed the approach and knew
we were going to have to find the runway regardless of the weather...
We saw the approach lights at about 400 feet AGL, almost 500 feet
below the localizer approach minimums. We landed without incident
(with two inches of ice). The approach and tower controllers were
We took off into forecast icing conditions... I thought if we could
get up high enough (10,000 feet) we could fly over the icing layer...
very thin layer of ice on the leading edge and upper wing surfaces
can cause a dramatic loss of lift and increase in drag. With two inches
of ice, these pilots were lucky to be near an airport.
by a sharp Center Controller not only helped an MD-80 crew out of
a bad situation, but also prevented a "chain reaction" of
traffic conflicts. This first report gives the Controller's perspective.
aircraft was in level flight at FL350, with some deviations off
course due to weather. At INTXN the pilot unexpectedly announced,
"We need to change altitude right now." Since I did not
control the airspace below FL350, I was unable to provide a descent
clearance right away. The pilot initiated a descent and I advised
the pilot that I was declaring an emergency and to please fill me
in on the situation when circumstances permitted...Subsequent discussion
with the pilot indicated that the aircraft was unexpectedly unable
to maintain altitude... The pilot asked for and received clearance
to FL310. Because I was sitting immediately adjacent to the controller
[handling] airspace below me, I was able to coordinate the un-cleared
descent quickly enough to avoid cascading problems with other aircraft.
And the following report details the
pilot's view of the same incident:
- ...Aircraft was in
cruise flight at FL350 with airfoil and engine anti-ice on. [We
were] in IMC deviating to the east of thunderstorms. Aircraft speed
increased initially from .76 to .78 Mach, then deteriorated to .69
Mach. Performance did not increase so we immediately descended to
a lower altitude to regain speed and aircraft control. There was
no time to request and receive clearance for the altitude change.
I believe we must have flown into relatively warm, moist air blowing
off the top of a storm to our left, causing marked deterioration
in aircraft performance.
It appears that the
aircraft may have been operating at, or close to, its performance
limit altitude for the thrust available and that the encounter with
the effects of the thunderstorm resulted in the inability to maintain
incidents may involve more drama, a snow-covered airport can be a
stage for a medley of errors.
Captain in this report stepped in on cue, but even with the help of
a proficient understudy, couldn't save the
ATIS indicated braking was good... Light snow was [also reported]
and [was] encountered on the approach, [but] was not present upon
landing. After my landing, we transferred controls at 60 knots and
the Captain started to taxi...He then called out that he couldn't
turn the aircraft. I looked up and saw we were sliding. I joined
him on the brakes as he put the power levers in full reverse. Both
of these inputs, along with tiller inputs, came to no effect. Our
nosewheel and right main gear went onto the grass...
Captain who submitted this report was all set for ice and snow, but
oil and rain stole the show.
had been raining lightly for about one hour. I was cleared for takeoff...[and]
...taxied onto the runway with slightly more than minimum power...
As I reached the centerline and turned the nosewheel handle there
was no response. The aircraft continued at a 45-degree angle toward
the edge of the runway. I applied max braking and could feel the
aircraft skidding as the anti-skid operated. The aircraft continued
traveling toward the left side of the runway, and I applied reverse
thrust to the engines. The aircraft was skidding and shuddering,
but stopped on the runway approximately 10-15 feet from the edge...
rain, in combination with oils from the asphalt and tire rubber
made a normal taxi onto the runway for takeoff a very slippery situation.
It has made me very wary of all wet runway and taxiway evolutions.
During the winter I tend to focus on snow and ice, but this situation...could
put you off a runway or taxiway when you are not expecting to slip.
the wings aren't "working" airplanes have to be "driven"
on runways and taxiways. Anyone who has lost control of a car on an
icy road knows the helpless feeling when the vehicle doesn't respond
to steering inputs. But imagine the emotions these two maintenance
technicians experienced when they lost control of a large, turbojet
aircraft. One of them describes the "impact" of cold-weather
taxi operations in his report to ASRS.
was assigned to taxi an aircraft with another technician. We were
to taxi...from the gate to a company hangar. My partner (the other
technician) took the left seat while I took right... We pushed out
from the gate and started engines. I got clearance from the ramp
[controller] to proceed south on the taxiway. As we were getting
close to our company hangar...our aircraft started sliding to the
left. My partner tried to reestablish control, tapping the brakes
even more and moving the tiller. He said, "We're sliding. The
nosewheel isn't turning the aircraft." We impacted [another
aircraft] in the gate...
after parking, an extended period of vigilance might be required when
there is ice on the ramp. After the chocks were put in and the engines
secured, the Captain who submitted the next report thought it was
time to leave…but so did the airplane.
to the gate was normal, with slush and ice on the taxiways and ramp.
I stopped the aircraft at the gate with normal use of brakes. External
power was connected, engines shut down, and the ramp agent signaled,
"chocks in." I returned the signal, verified both engines
off, and released the brakes. The First Officer stated that the
shutdown checklist was complete. I left my seat to open the cockpit
door. While unlocking the door, I felt a hard jolt. Initially, I
thought the jetway had hit the aircraft, but when I looked outside,
the jetway was not near us. The First Officer reported that the
aircraft had rolled backwards. He applied the brakes as soon as
he was aware of the motion. The jolt was the aircraft stopping abruptly.
I turned the seatbelt sign on again, and made an announcement for
the passengers to be seated so that the aircraft could be towed
back into position…The aircraft was towed back to the stop
point, chocks reinstalled, and brakes set. The ground crew said
that the…ramp was so slippery that the aircraft slid backwards
with the chocks in place...
Recently Issued Alerts On...
lavatory fire incident
Kitfox rubber hose failure
uncommanded nose gear retraction
SID discrepancy at a Mexican airport
international airport's taxiway signage and marking
2002 Report Intake
Carrier/Air Taxi Pilots