Aircraft Deicer Trucks Maintenance

Association of European Airlines (AEA) defines Deicing as a procedure by which frost, ice, slush, or snow is removed from an aircraft to provide clean surfaces. Often, deicing is misunderstood to be the same as Anti-icing, which is a preventive procedure to protect against the formation of frost or ice and accumulation of snow or slush on treated surfaces of the aircraft for a limited period (holdover time).

 

The Federal Aviation Administration (FAA) requires aircraft surfaces to be deiced and anti iced to ensure the safety of passengers. There are two basic types of deicing/anti-icing operations carried out at airports: the deicing/anti-icing of aircraft and the deicing/anti-icing of paved areas, including runways, taxiways, and gate areas.

 

Deicing – Operational Principle and Types:

As defined, deicing follows a stepwise procedure to remove Ice, snow, slush, or frost from aircraft surfaces by heated fluids, mechanical methods, alternate technologies, or combinations. Basically, deicing is based on the principle that heat in a fluid effectively melts any frost and light deposits of snow, slush, and ice. Heavier accumulations require heat to break the bond between the frozen deposits and the structure; the hydraulic force of the fluid spray is then forced to flush off the residue.

The following is the standard procedure laid out by AEA and accepted as an international standard for deicing using fluids.

 

Stage 1: Preparing the surface or Pre-step process: Upon mutual consent with the aircraft operator, a pre-step process before the de-icing process can be carried out to remove large amounts of frozen contamination (e.g., snow, slush, or ice). The pre-step process may be performed with several methods, such as using brooms, forced air, heat, heated water, and heated fluids with a negative buffer freezing point. The pre-step process can help in reducing the quantity of glycol-based de-icing fluid required during the main de-icing process..

Stage 2: Removal of frost and light ice: A nozzle setting giving a solid cone (fan) spray should be used to ensure the largest droplet patter and retain the maximum heat in the fluid.

Stage 3: Removal of snow: A nozzle setting sufficient to flush off deposits and minimize foam production is recommended. Heavier deposits often require heavier fluid flow to remove snow from the aircraft surfaces. For light deposits (both wet and dry snow), similar procedures as for frost removal may be adopted.

Stage 4: Removal of ice: Heated fluid shall be used to break the ice bond. The method makes use of the high thermal conductivity of the metal skin. A stream of hot liquid is directed at close range onto one spot at an angle of less than 90° until the aircraft’s skin is just exposed.

Note: By applying the heated fluid close to the aircraft skin, a minimal amount of fluid will be required to melt the deposit and save operational costs.

Other de-icing techniques:

 

Deicer Trucks:

Aircraft deicing trucks are mounted with a crane-lifted basket, wherein the operator sits in the basket and controls the deicing fluid sprayer. Trucks typically consist of up to 30,000-gallon glycol tanks with propylene glycol and water mixture for deicing. The tank is connected to the hose and nozzle system to spray glycol onto the aircraft surface. Deicing trucks are powered by Internal Combustion Diesel Engines, which provide rotational power to pumps to spray glycol through nozzles up to 200 LPM, varying flow.

 

Deicer Trucks – Boom and Load Tests:

Deicer Boom trucks consist of a rotating telescopic-boom crane mounted on the truck chassis. This configuration allows for ease of lifting equipment transporting to job sites and allows the boom truck to maximize utilization during a deicing process. Boom tests are usually performed to test the strength of the crane and lift ability. New York state code rule 23-8 lays out procedures for testing Mobile Cranes, Towers, and Derricks.

 

Preventative Maintenance Program for Deicer Trucks:

The AEA has laid out standard De-icing/anti-icing procedures, which sternly mention that the operations be carried out exclusively by personnel trained and qualified on this subject. Companies providing de-icing/anti-icing services should have both a Qualification Programme and a Quality Assurance Programme to monitor and maintain an acceptable level of competence.

FAA Considers the Deicing program as critical ground support equipment, and hence proper maintenance and inspection are vital. Following are the inspection and PM guidelines are laid out by the DEPARTMENT OF THE AIR FORCE, Headquarters US Air Force, Washington, D.C. 20330-1030.

 

  1. Vehicle Overview: Review the AF Form 1800, Ensure that any existing discrepancy has been corrected, and check for Damage or vehicle leaning to one side, Fresh leakage of fluids, and Hazards around the vehicle
  2. Engine Compartment: Inspect the Engine oil level, Coolant level in the radiator; condition of hoses, Power steering fluid level; hose. condition (if so equipped), Windshield washer fluid level, battery fluid level, connections and tie-downs, Automatic transmission fluid level, belts for tightness and excessive wear (alternator, water pump, air compressor)
  3. Leaks in the engine compartment: Fuel, coolant, oil, power steering fluid, hydraulic fluid, battery fluid).
  4. Electrical harness: Cracked, worn electrical wiring insulation.
  5. Oil pressure: Once the engine is started, the level Should come up to normal within seconds after the engine is started.
  6. Air pressure: Pressure should build from 50 to 90 psi within 3 minutes. Build air pressure to governor cut-out (usually around 120 – 140 psi).
  7. Ammeter and voltmeter: Should be in the normal range(s).
  8. Coolant temperature: Should begin gradual rise to normal operating range.
  9. Engine oil temperature: Should begin gradual rise to normal operating range (not more than 100 degrees Celsius)
  10. Check Signal Lights: All signal lights – turning lights, left rear and right rear lights, and color intensity should be inspected.
  11. Hydraulic systems: Test for hydraulic leaks, especially from the Brake system and Parking brakes.
  12. Nozzles and spray systems: Inspect for leaks and nozzle clogging, which can build up pressure and deteriorate the pumping systems
  13. Pumps: Spray pumps are to be tested for efficiency and discharge pressures at varying flow rates.

 

A Deicer Truck PM plan should also include load bank and boom testing to check the engine’s performance and boom load-carrying capacity. These tests simulate the high load on the engine and the cranes as a part of preventive maintenance activity.

 

Why are Deicer Truck Calibration and Preventative Maintenance essential?

Aircraft operators should assimilate that a Deicer vehicle is not just a truck. Every time while performing a deicing operation, glycol is sprayed onto the expensive Aerofoil design, and there is a potential risk of damaging the aircraft components. Therefore, it is essential to deliver clean, carefully regulated glycol while performing deicing operations. An accidental or unregulated flow could destroy sensitive and expensive aircraft electronic and avionics systems.

 

e2b calibration offers industry-leading consultancy and certified PM services for your aircraft Deicer Trucks. At e2b Calibration, we maintain and troubleshoot your deicing trucks so that you can concentrate on maintaining your aircraft. Our labs are ISO/IEC accredited and operated by a team of qualified experts providing training and consultancy services on Deicing truck maintenance and inspection. Our verifiable services are unmatched in the industry. Contact e2b calibration for all your equipment calibration needs.

 

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