Aircraft Inspection Requirements Following De-Icing / Anti-Icing

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Sofema Online (SOL) www.sofemaonline.com considers De-icing best practices compliant with Aerospace Standard AS6285 REV.E & ICAO Document 9640

Introduction

The post-de-icing check ensures that the treated surfaces are no longer contaminated.

This check is made visually immediately following the application of de-icing/anti-icing fluids. A qualified person carries it out according to the approved air operator plan and procedures.

  • • This check should include any part of the aeroplane on which a de-icing/anti-icing treatment was performed according to the requirements identified during the contamination check.

Aircraft Inspection Requirements after Deicing/Anti-Icing

Following the deicing/anti-icing procedures and before takeoff, the critical aircraft surfaces shall be free of all frost, snow, slush, or ice accumulations following the following requirements.

  • • Wings, Tails, and Control Surfaces

- Wings, tails, and control surfaces shall be free of frost, snow, slush, or ice unless the aircraft manufacturer and state regulatory authority permit that a coating of frost may be present on wing lower surfaces in areas cold-soaked by fuel between forward and aft spars; and on upper wing surfaces within defined areas, following the aircraft manufacturer’s published documentation.

NOTE: Except for frost due to cold-soaked fuel as mentioned above, and unless otherwise specified in the Aircraft Flight Manual or other aircraft manufacturer’s documentation, contamination is not acceptable on the upper or lower surfaces of the horizontal stabilizer and elevator/tab; strakes; inboard, outboard, upper, and lower surfaces of the wing and wing tip devices; and either side of the vertical stabilizer and rudder.

  • • Pitot Tubes, Static Ports, and All Other Air Data Sensing Devices

- Pitot tubes, static ports, angle of attack sensors and other air data sensing devices shall be free of frost, snow, slush, ice, and fluid.

NOTE: Ice ridges can form on different aircraft areas, especially on the nose of the fuselage, while on the ground. These ridges disrupt airflow into the air data sensing devices, which can result in false measurements. All contamination shall be removed from these areas.

Engines

  • • Engine inlets (including the leading edge), exhaust, thrust reversers, cooling intakes, control system probes, vortex dissipators, and ports shall be free of frost, snow, slush, or ice. Engine fan blades, propellers (as appropriate), and spinner cones shall be free of frost, snow, slush, or ice and shall be free to rotate.

Air Conditioning Inlets and Outlets

  • • Air inlets, outlets, pressure-release valves, and outflow valves shall be unobstructed and free of frost, snow, slush, or ice.

Landing Gear and Landing Gear Doors

  • • Landing gear and landing gear doors shall be unobstructed and free of frost, snow, slush, or ice. Do not spray deicing/anti-icing fluids directly onto wiring harnesses, electrical components (receptacles, junction boxes, etc.), brakes, and wheel components.

Fuel Tank Vents

  • • Fuel tank vents shall be free of frost, snow, slush, or ice.

7.7 Fuselage

  • • The fuselage shall be free of ice, slush, and snow. According to the aircraft manufacturer’s documentation, frost may be present on the fuselage for take-off within specified amounts, provided that no other forms of contamination are present and inlets, outlets, and other devices (as identified by the aircraft manufacturer) are free of contamination.
  • • Flightdeck Windows and Nose or Radome Area
  • • Any significant deposits of frost, snow, slush, or ice on the flight deck windows or in areas forward of them shall be removed before departure. Heated flight deck windows will not usually require deicing.

Any forward area from which fluid may flow back onto flight deck windows during taxi or subsequent takeoff shall be free of fluid before departure.

Note:

  • • If SAE Type II, III, or IV fluids have been used, all fluid traces on flight deck windows shall be removed before departure, with particular attention paid to windows fitted with wipers.
  • • Thickened fluid (SAE Types II, III, or IV) can be removed by using a diluted Type I mixture, water (where it has been determined that refreezing will not occur), a manual method (ensuring that windscreen heat is turned off), or another cleaner as approved by the aircraft manufacturer.

Note: During falling precipitation, heated windows may cause liquid effluent to freeze near sensors, requiring deicing.

Dried Thickened Fluid Residues When the Aircraft Has Not Been Flown after Anti-Icing

  • • Dried thickened-fluid (SAE Types II, III, or IV) residues can occur when surfaces have been deiced/anti-iced, but the aircraft has not been flown and is not subject to precipitation. The fluid may then have dried on the surfaces.
  • • In such situations, the aircraft must be checked for dried residues from thickened fluids and cleaned as necessary.

Special Maintenance Considerations

Proper account should be taken of the possible side effects of fluid use. Such effects may include, but are not necessarily limited to, dried and rehydrated residues and the removal of lubricants.

Next Steps

For Training Related to Aircraft De-Icing & Anti-Icing, please see www.sassofia.com and www.sofemaonline.com. For a complete list of all our courses, check here. For questions, please email [email protected]

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