De-icing and anti-icing on the ground - OM A Flashcards
Icing conditions on the ground can be expected when air temperatures fall below ___°C and when….
10°C;
visible moisture in any form is present, such as clouds, freezing fog, fog with visibility of 1 SM/1600m or less, rain, sleet, snow, freezing precipitation, frost, hail, ice pellets, or high humidity (on cold soaked wings).
Do not attempt a take-off in the following weather conditions:
(Because there is NO HOT for these precipitations)
Moderate and heavy freezing rain;
Heavy snowfall;
Heavy Ice pellets;
Small hail and hail.
Which type of anti-icing fluid is not allowed?
TYPE 3.
Company policy
Who is responsible for the aerodynamic cleanliness of the aircraft during ground manoeuvring all the way till take-off?
The Commander.
What is the required action when in doubt about the aerodynamic cleanliness of the aircraft?
The commander shall perform (or have performed) an inspection of the critical surfaces or simply request a further de/anti-icing treatment.
What is the main requirement regarding the critical surfaces to allow takeoff?
The commander shall never commence a take-off unless ALL the critical surfaces are free of frost, ice, snow contamination or any other deposits.
What is the responsibility of the maintenance crew in case of possible contamination of the aircraft’s surfaces?
Maintenance crew are responsible to check the aircraft for the need to de-ice. Based on own judgement they shall notify the commander.
What is a Pre-flight contamination check?
A visual contamination check of the aircraft performed by the FLIGHT CREW to establish the need for de-icing.
The presence of which type of contamination on the aircraft surfaces doesn’t require deicing?
A light coatings of frost, up to 3mm in thickness, on lower wing surfaces.
Which surfaces must be checked to ensure they are free from contamination during the Pre-flight contamination check?
- Wing surfaces including leading edges and any wingtip fences/sharklets;
- Horizontal stabiliser upper and lower surface;
- Vertical stabiliser and rudder;
- Fuselage;
- Engine cowls, intakes and fan blades;
- Air data probes, AOA sensors, and static vents;
- All intakes and outlets;
- Landing gear and wheel bays/wells;
- Nose of the fuselage;
Exceptions to the above are light coatings of frost, up to 3mm in thickness, on lower wing surfaces.
What is a Post de-icing check?
The confirmation given by the ground crew upon completion of the de/antice treatment, indicating that a post de-icing check has been completed. It is given as part of the anti-icing code and transfers the responsibility for the condition of the aircraft to the commander.
What is a Pre-take-off contamination check?
A check conducted by AUTHORIZED ground crew, required when the critical surfaces of the aircraft cannot be effectively assessed by a pre-take-off check or the HOT has been exceeded and precipitation still exists. Must be completed within 5 minutes of the start of the take-off roll.
For which type of precipitations is required to refer to the Snowfall intensities tables?
Snow, Snow Grains, Snow Pellets. (FAA HOT Guidelines 2024-2025 - TABLE 48)
In case of simultaneous presence of Snowfall and obscuring phenomenon (fog, haze, smoke, etc), is the use of Snowfall intensities tables still allowed?
The use of Snowfall intensities tables in ALL snow conditions, with or without obscurations is recommended (FAA HOT Guidelines 2024-2025 - TABLE 48).
When does the HOT start in case of a 1-step treatment and a 2-step treatment?
The HOT begins with the start of the de/anti-icing application in the case of a one-step operation, or the beginning of anti-icing application in a two-step process.
Can the HOT be disregarded to account for improving weather conditions?
NO.
What are the sources for the HOT calculation?
In order of priority:
1) SureWx application on portable EFB;
2) SureWx application contacting flight dispatch;
3) FAA HOT tables.
When shall the Adjusted HOT be used?
Adjusted HOT tables shall be used whenever the flaps/slats are configured to the take-off configuration prior to beginning the de/anti-icing treatment.
Calculation of HOT using SureWx or the FAA tables: What lower and upper time limits of the range indicate?
When using Metar to determine HOTs, the lower time limit of the range indicates the estimated time of protection during MODERATE precipitation whilst the upper limits indicates the estimated time of protection during LIGHT precipitation.
What must always be performed after a de/anti-icing treatment?
A post de-icing check shall always be carried out after the de/anti-icing.
What are the requirements for a localized de-icing?
The affected area(s) shall be sprayed with a heated fluid/water mixture suitable for a one-step procedure;
Both sides of the aircraft are treated symmetrically (same areas, same amount and type of fluid, same mixture strength), even if the contamination is only present on one side.
Is the Infrared de-icing allowed?
NO.
Company Policy
What is the content of the anti-icing code?
The report provided by the GND staff after completion of the treatment
The fluid Type;
The fluid name (except for Type I);
Concentration (except for Type I);
The local time when the final de/anti-icing application began;
Confirmation that the post de-icing check has been completed.
After a de/anti-icing treatment, the commander shall make a relevant entry on the following documents:
ATL and FOL.
