Chapter 6 - Aircraft Critical Surface Contamination Examination Questions

3.0  Deicing/Anti-icing Fluids

3.01  Holdover time is

  1. a fixed time for fluid breakdown specified by the manufacturer.
  2. a fixed time for fluid breakdown specified by the ISO and SAE standards.
  3. the estimated time that an application of deicing/anti icing fluid is effective in preventing frost, ice or snow from adhering to treated surfaces.
  4. the estimated time to fluid shear from the aircraft surfaces.

3.02  The term "holdover time" as applied to anti icing or deicing fluids is the

  1. recommended maximum storage time in approved containers.
  2. recommended maximum time the fluid should be allowed to remain on the aircraft surface to avoid corrosion.
  3. estimated spray application time.
  4. estimated time the fluids will prevent frost, ice, or snow from forming or accumulating on the treated surface of an aircraft.

3.03  Pure 100% ethylene glycol should not be used for deicing in non precipitation conditions because

  1. the freezing point is higher than fluids with a proper glycol/water ratio.
  2. this fluid is highly corrosive unless diluted with water.
  3. undiluted, it is highly flammable.
  4. it could cause a loss of efficiency of the lifting surfaces due to its higher viscosity.

3.04  Undiluted propylene glycol at temperatures less than 10°C is quite viscous and may produce a reduction in lift of approximately

  1. 10%.
  2. 20%.
  3. 30%.
  4. 40%.

3.05  The reason deicing fluid acts as an anti icing fluid for a very limited time is because

  1. it does not mix well with water.
  2. it mixes well with water.
  3. it has a relatively high viscosity.
  4. the FPD has a relatively high freezing point.

3.06  Substances approved for use on pneumatic boots to improve deicing performance

  1. may also be used to enhance anti icing of the wing and tailplane leading edges.
  2. are not to be used for other purposes unless approved by the aircraft manufacturer.
  3. may also be used in anti icing windows.
  4. are not to be used for other purposes under any circumstances.

3.07  Snow falling on an aircraft that has been de iced will cause the deicing fluid to lose its effectiveness because

  1. its molecular sheer structure breaks down.
  2. the melting snow lowers its temperature.
  3. it becomes saturated, allowing the water to reach the aircraft skin and freeze.
  4. the freezing point at the top of the film of fluid is less than at the bottom.

3.08  The heating of freezing point depressant (FPD) fluids

  1. decreases their deicing effectiveness.
  2. increases their deicing effectiveness.
  3. has no effect on their deicing effectiveness.
  4. has no effect on their anti icing effectiveness.

3.09  SAE Type II and Type IV anti icing fluids are usually applied

  1. directly to snow and ice covered aircraft.
  2. after the aircraft has been de iced conventionally.
  3. mixed with hot water in a 50/50 ratio.
  4. with deicing fluid in one pass.

3.10  SAE Type II and Type IV anti icing fluids are effective anti icers because they

  1. adhere to stationary lifting surfaces.
  2. shed most of the fluid during take off.
  3. provide longer protection than type I deicing fluid.
  4. accomplish all of the above.

3.11  SAE Type II and Type IV anti icing fluids

  1. do not affect the lift of the wing.
  2. are contaminants and are designed to flow off on take off.
  3. reduce surface friction and decrease drag.
  4. change the angle of attack required for lift off.

3.12  Select the correct statements about SAE Type II and Type IV anti icing fluids.

  1. They do not adhere to the stationary lifting surfaces.
  2. Their viscosity is very low, even at low airspeed.
  3. They are recommended for use on all types of commercial aircraft.
  4. They readily flow off the surfaces of large aircraft on take off.
  1. A, B, C.
  2. B, C, D.
  3. C.
  4. D.

3.13  SAE Type II anti icing fluids provide

  1. the required "clean" aircraft condition before the application of deicing fluid.
  2. a degree of holdover time protection from further frost, ice or snow accumulation.
  3. unlimited holdover time protection from further frost, ice or snow accumulation.
  4. holdover time protection against further accumulation based solely on the viscosity.

3.14  The performance of SAE Type II anti icing fluid applied with improper equipment may be reduced by at least

  1. 80% to 90%.
  2. 50% to 80%.
  3. 30% to 40%.
  4. 20% to 60%.

3.15  The use of SAE Type II and Type IV anti icing fluids are recommended for aircraft with rotation speeds above

  1. 75 kt.
  2. 85 kt.
  3. 95 kt.
  4. 100 kt.

3.16  The acceptable Decision Criteria Times are the

  1. median times in the holdover tables.
  2. times shown in the Ground Icing Operations Standard.
  3. shortest time within the applicable holdover timetable cell.
  4. longest time within the applicable holdover timetable cell.

3.17  A Type II fluid has met an acceptance test down to -42ºC. The reported freezing point as measured by the deicing operator is -40ºC. The OAT is -35ºC. Calculate the Lowest Operational Use Temperature (LOUT).

  1. -33ºC.
  2. -35ºC.
  3. -40ºC.
  4. -42ºC.

3.18  Refer to Appendix:  SAE Type I Fluid Holdover Times (Table 1)

Moderate snow is falling and the reported outside air temperature is 5°C. Your aircraft is de iced and anti iced with SAE Type I fluid. What is the minimum holdover time you could expect?

  1. 5 minutes.
  2. 6 minutes.
  3. 8 minutes.
  4. 11 minutes.

3.19  Refer to Appendix:  SAE Type II Fluid Holdover Times (Table 2)

Freezing fog is present and the outside air temperature is 2°C. Your company uses the Ground Icing Operations Standard and your aircraft is anti iced with an undiluted SAE Type II fluid. What is the acceptable Decision Criteria Time for these weather conditions?

  1. 25 minutes.
  2. 35 minutes.
  3. 1 hour.
  4. 1 hour, 30 minutes.

3.20  Refer to Appendix:  SAE Type IV fluid Holdover Guidelines (Table 3)

Snow is falling and the temperature is 2°C. The ground operator has just completed the deicing/anti icing of your aircraft and advises you that the holdover time is between 25 and 35 minutes. According to the Holdover Times Table, the SAE Type IV fluid concentration used on your aircraft was

  1. 100/0.
  2. 75/25.
  3. 50/50.
  4. 25/75.

3.21  Refer to Appendix:  SAE Type IV fluid Holdover Times (Table 3)

Light freezing rain is falling with an OAT of 0°C and a 50/50 mixture of SAE Type IV fluid is used. What is the acceptable Decision Criteria Time for these weather conditions?

  1. 5 minutes.
  2. 10 minutes.
  3. 15 minutes.
  4. 30 minutes.

3.22  Refer to Appendix:  SAE Type IV Fluid Holdover Times (Table 3)

Freezing drizzle is present and the outside temperature is 12°C. Your company uses the Ground Icing Operations Standard and your aircraft is anti iced with a 100/0 mixture of SAE Type IV anti icing fluid. What is the acceptable Decision Criteria Time for these weather conditions?

  1. 0 minutes.
  2. 15 minutes.
  3. 20 minutes.
  4. 40 minutes.

3.23  Refer to Appendix:  Snow Visibility vs Snowfall Intensity Chart (Table 4)

The daytime visibility in snowfall is 1/2 of a statute mile and the temperature is -80 C. The snowfall rate that will be used to determine which HOT table value is appropriate for the fluid in use is

  1. light.
  2. moderate.
  3. heavy.
  4. very heavy.
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