Aircraft Icing Flashcards
What conditions are conductive to the formation of rime ice on an airfoil?
Low temperatures, lesser amounts of liquid water, low velocities, and small droplets
RIME ice is rough, milky, opaque ice formed by the very rapid freezing of super cooled droplets as they strike the aircraft
What conditions are conductive to the formation of clear ice on an airfoil?
Temperatures close to freezing point, large amounts of liquid water, high aircraft velocity, and large droplets
CLEAR ice is a glossy transparent ice cormed by the relatively slow freezing of super cooled water.
WHen freezing rain is encountered, what assumption can the pilot make about the conditions in the surrounding air?
A temp inversion exists and there is warmer air ABOVE
Freezing rain forms when the rain become supercooled by falling through a subfreezing layer of air. Ordinarily, air temps decrease with the increase of altitude, but freezing rain requires a temp inversion.
What should the pilot suspect and what is the appropraite corrective action if the pilot experiences the following after flying through icing conitions?
- Elevator control pulsing, oscillations, or vibrations
- abnormal nose down trim change
- sudden uncommanded nose down pitch when flaps are lowered to the approach position
Suspect an ice induced tailplane stall. Correct by retractinf the flaps and applying appropriate nose up elevator pressure. Utilize suffiecent airspeed and power for a no-flap approach and landing
Why is frost considered hazardous to flight operation?
Frost causes early airflow separation resulting in a loss of lift
The roughness of frost spoils the smooth air flow over the air foil causing a slowing of air. This causes early airflow separation resulting in a loss of lift.
What is an operational consideration if you fly into rain which freezes on impact?
Temps are above freezing at some higher altitude.
Rain fallling through colder, sub-freezing air may become supercooled and turned into ice upon imact with an airframe. This is known as freezing rain and indicates that temps are above frezing at some higher altitude.
Ice accumulations forward of the ailerons during a supercooled large droplets (SLD) icing encounter can lead to a roll upset. Initiate recovery from a roll upset by
reducing the angle of attack through an increase in airspeed or by exteding the wing flas to the first settiing
If in a turn, the wings should be brought to level.
Which precipitation type normally indicates freezing rain at higher altitudes?
Ice pellets
Rain falling through colder air may become supercooled, freeze, and fall as freezing rain or ice pellets. Ice pellets always indicate freezing rain at higher altitudes.
Which conditions results from the formation of frost?
Temp of the collecting surface is below the dewpoint of surrounding air and the dewpoint is colder than freezing
Frost forms in much of the same way as dew. The difference is that the dew point of the srrounding air and the collecting surface must be cooler than freezing.
Which family of clouds is least likely to contrinute to structural icing on an aircraft?
high clounds
The high cloud famiily is cirrifuorm includes, cirrus, cirrocumulus, and cirrostratus. They are composed almost entirel of ice crystals. Thus, ice will not adhere to the aircrat of the aircraft
What pilot actions would be appropriate during an icing encounter in cumuliform clouds
Activate installed deicing equipment per manual, and maintain current heading to exit hold. avoid extended flight in a series of cumuiform clounds. Deviate around the cloud when possibe
When should a pilot expect airframe icing?
WHen flying in visible moisture, such as rain or cloud droplets and the temp is between +02 and -10 cesius
