5. PUSH BACK.

Push back

At ESGG the pushback clearance is coordinated via the ground personal. We do not need to call the tower and ask for push.

The first person to contact is therefor our mechanic. This conversation is a mix of Swedish and English, normally referred to as "SASPIRANTO".
  • 1. We receive "Departure check performed" this is a must before every start up. Next in Swedish "Wings are clear, no ice" this is also a must. In this departure, I have already discussed the ice situation when I received the fuel papers from our mechanic. The wings were clear, no need for deicing.
  • 2. Brakes off and clear for push.
Next call is during the push back.
  • 1. All engines - clear to start. Bad quality due to the wind in the mech microphone.
  • 2. Some concern from the Mech regarding the wind. We are turning with the tail into the wind and this might give high temperature during engine start.
  • 3. Brakes on and engine is running.
  • 4. Disconnecting.

ICING CONDITIONS.

Today only engine ice is present. This is a short description of the whole procedure to make a departure during icing conditions.

ENGINE ICE.

During ground operation (use OAT), takeoff and approach (use RAT), engine anti-ice shall be used whenever the temperature is +6°C or less and either the dewpoint is at or within 3° of ambient temperature or moist conditions are evident ( such as rain, sleet, snow, fog or water, ice on the taxiway or runway). Engine anti-ice shall also be turned on before entering clouds when RAT is between +6° and -10°.

During ground operations at temperatures of +3° or below and simultaneous high moisture conditions (rain, sleet, snow or fog) the engine anti-ice system may not be capable of keeping the engines clear of ice during prolonged taxiing and/or long periods of idling. Periodic run-ups (70% N1 for a minimum of 15 seconds or alternately 60% for minimum of 40 seconds) shall be made in these conditions. Such run-ups need not normally be made more frequently than at 10 minutes intervals.

All takeoffs during this condition or after de/anti-ice treatment shall be preceded by an engine run-up.

AIRFOIL ICE.

Before departure the aircraft shall be free of ice, snow and slush on the wings, tail surface and fuselage.

Frost on the underside of the wing tank area is permitted provided the thickness does not exceed 3 mm. No performance corrections for this condition is required.

If taking off in icing conditions, the airfoil anti-ice system shall be switched on before takeoff to permit airfoil anti-ice immediately after liftoff. The system is not active during ground operation.
Airfoil icing conditions can exist when RAT is 6° or less and there is visible moisture in the air. Be alert for ice buildup on windshield wipers or edges of windshields.

During flight in continuous icing conditions, operate the tail de-ice system approximately every 20 minutes and also about one minute before final flap setting.

ANTI-ICE TREATMENT.

First some definitions.

Anti-icing.
Anti-icing is a precautionary method by which clean or de-iced aircraft surfaces are protected against the formation of frost or ice, or accumulation of snow or slush, for limited period of time.

De-icing.
De-icing is a procedure by which frost, ice and snow is removed from the aircraft surfaces.

Holdover time HOT.
Holdover time is the estimated time the anti-icing fluid will prevent frost, ice and snow to form or accumulate on the protected (treated) areas of the aircraft. HOT starts at the beginning of the final anti-ice treatment. A HOT table is published, giving HOT as a function of applied fluid, temperature and weather. For each condition the table gives a range of HOT (eg 30-45 minutes) and it is the responsibility of the Commander to determine what HOT can be expected under prevailing conditions.

DE/ANTI-ICING

De/anti-icing is a combination of de-icing and ant-icing. It can be performed in one or two steps:

One step de/anti-icing is performed with a anti-icing fluid. The fluid used to de-ice the aircraft remains on the treated surfaces and provides anti-icing capability. The correct fluid and concentration shall be chosen with regard to desired HOT, and dictated by ambient/aircraft surface temperature and weather conditions.

Two step de/anti-icing. The first step (de-icing) is normally performed with hot water or a heated anti-ice fluid mixture. The correct fluid shall be chosen with regard to the temperature, and shall provide protection of treated surfaces until the second step is performed. the second step (anti-icing) is an overspray with hot or cold anti-icing fluid. The correct fluid and concentration shall be chosen with regard to desired HOT, OAT or aircraft skin temperature (whichever is lowest) and prevailing weather conditions.


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