August 30, 2021

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Sofema Aviation Services (SAS) www.sassofia.com Presents considerations related to best practice communication procedures during Ground De-icing / Anti-icing Operations.

Introduction – What can happen when it all goes wrong!

https://www.tsb.gc.ca/eng/rapports-reports/aviation/1995/a95q0015/a95q0015.html

Case Study – Collision with vehicle Royal Air Maroc

Boeing 747-400 CN-RGA Montreal (Mirabel) International Airport, Quebec 21 January 1995

Synopsis

The Royal Air Maroc Boeing 747-400 was parked in the de-icing centre of Montreal (Mirabel) International Airport, Quebec.

  • The aircraft was being prepared for a scheduled flight from Mirabel to Casablanca, Morocco, with a stop at New York, New York.
  • The four engines were running during the de-icing operation.
  • The crew heard “dĂ©givrage terminĂ©” (de-icing completed), and the captain asked the co-pilot to inform the apron controller that the aircraft was ready to taxi.
  • Taxi instructions were issued.
  • The aircraft started to move forward and overturned the two de-icing vehicles that were still in front of the aircraft’s horizontal stabilizers.
  • The two-vehicle drivers sustained minor injuries; the three occupants of the cherry-pickers received fatal injuries.

Accident Findings

The Board determined that the flight crew started to taxi the aircraft before its perimeter was clear, following confusion in the radio communications.

The following factors contributed to the accident:

  • A lack of de-icing procedures within Royal Air Maroc;
  • Non-compliance with procedures on the part of the Canadian Airlines International Ltd. de-icing crew;
  • Inadequate or inappropriate communications equipment;
  • Incomplete training of Snowman 1 (the chief de-icing attendant);
  • A regulatory framework less demanding of foreign air carriers than of Canadian carriers;
  • A lack of operational supervision; and a lack of adherence to radio protocol.

Conclusion & Steps to Prevent Re-occurrence

This terrible accident with a tragic loss of life shows us clearly the importance of controlled and positive communication throughout and during the conclusion of the De-icing / Anti Icing operations.

Communication Protocols

Effective communication is of critical importance to the effectiveness of aircraft ground de/anti-icing. The aircraft commander must receive accurate information on the fluid treatment carried out.

What does EASA require – Ref GM1 CAT.OP.MPA.250 Ice and other Contaminants — Ground Procedures (ED Decision 2021/005/R)

Anti-Icing Codes

Upon completion of the anti-icing treatment, qualified staff provides the anti-icing code to the flight crew as follows:

  • The fluid Type.
  • The fluid name (except for Type I).
  • Concentration (except for Type I).
  • Local time at the start of anti-icing.
  • Date (optional).
  • The statement ‘post- de-icing/anti-icing check completed’ (if check completed).

Example:

‘TYPE II / MANUFACTURER, BRAND X / 75% / 1335 / 15FEB20 / POST- DE-ICING/ANTI-ICING CHECK COMPLETED’.

When a two-step de-icing/anti-icing operation has been carried out, the anti-icing code should be determined by the second step fluid.

Communication Protocols

  • Communication should be in a standardised format.
  • This should be achieved by the use of a standard format Anti Icing Code to ensure that there is no possibility of misunderstanding in respect of the minimum required information.
  • Relevant additional information can and should be passed as well.

The Code communicates the following information to the aircraft commander by referring to the last step of the fluid treatment procedure in the following sequence:

  • The fluid type – Type 1 Fluid, Type 2 Fluid, Type 3 Fluid, or Type 4 Fluid.
  • The fluid concentration within the fluid/water mixture, expressed as a percentage by volume (this is not required for Type 1 Fluid).
  • The local time in hours and minutes at the beginning of the final (or only) de-icing/anti-icing step.
  • (optionally, for Type 2 and 4 Fluids only) the complete name of the anti-icing fluid (the “brand name”).
  • The statement “post de-icing/anti-icing check completed”.

By Example: A de-icing/anti-icing procedure in which the last step was the use of a mixture of 75% of a type 2 fluid and 25% water which commenced at 1335 local time is communicated as follows:

“TYPE 2/75 1335 [optional complete name of anti-icing fluid] post de-icing/anti-icing check completed”

Note: Communication of the anti-icing code and any related supplementary information can be by R/T, intercom, or message board display.

For Recordkeeping purposes at the service provider, the date of the treatment should also be recorded in the sequence day, month, year.

Example of Communication Procedures

Communication between the flight crew and the ground staff (call sign “Snowman”) on the remote de-icing position is carried out via VHF frequency xxx.xxx

The frequencies are listed in the appendix and are transmitted to the flight deck crew if required by means of an information board.

The whole de-icing procedure has to be coordinated via VHF frequency between the flight deck crew and the ground personnel.

The coordination must entail:

  • Fluid type(s)
  • Mixing ratios (especially type 4)
  • Aircraft parts to be de-/anti-Iced
  • Current Outside Air Temperature (OAT) or/and Wing/fuel temperature

Communication call signs on remote de-Icing Stand

Call sign Flight Deck Crew: registration of aircraft (i.e. “PH-ABC”)

Call sign de-icing ground staff: Snowman plus number of car (i.e. “Snowman 4”)

Communication prior to the de-/anti-icing procedure:

Flight deck Snowman

“PH-ABC from Snowman 4”

“Snowman 4 from PH-ABC”

“PH-ABC my recommendation is: OAT xx°C 2-step procedure with Type 1 and Type 4 100%

For wings and stabilizers, do you agree?

And please state your wing/ fuel temperature“

„ Fuel temperature equals OAT“ “Snowman 4 we accept your recommendation“

“PH-ABC, is the aircraft ready for de- icing?”

“Snowman 4, the aircraft is configured ready for de-icing.”

“PH-ABC, we start with the de-icing now and call you when we’re finished.”

Communication after the de-/anti-icing procedure :

Flight deck Snowman “PH-ABC from Snowman 4”

“Snowman 4, go ahead.” “PH-ABC we have completed the de-/anti-icing with Type 1 followed by Type 4 for wings and stabilizers.

Your Anti-icing code is: Type 4 100% at 1300 local time. Post de-/anti-icing check is performed.”

“Confirm, wings and stabilizers de-iced. Anti-Icing Code: Type 4 100% 1300 local time”

“PH-ABC from Snowman4, I’ll give you the “All Clear Sign” from the right side.

Good Bye”

“All Clear Sign from the right.

Thank you. Good bye.”

General Guidance Regarding Communication Procedures

  • The person communicating with the flight crew shall have a basic knowledge of the English language in order to communicate properly.
  • De-icing/anti-icing operation – An aircraft shall not be dispatched for departure after a de-icing/anti-icing operation until the Commander has been notified of the type of de-icing/anti-icing operation performed.
  • The standardised notification performed by qualified personnel indicates that the aircraft critical parts are checked free of ice, frost, snow, and slush, and in addition includes the necessary de-icing/anti-icing code as required to enable the Commander to estimate the holdover time to be expected under the prevailing weather conditions.

Note 1: If two different companies are involved in the de-icing/anti-icing treatment and post de-icing/anti-icing check, it must be ensured that the Anti-Icing Code is not given before the post de-icing/anti-icing check is completed.

Note 2: The company carrying out the de-icing/anti-icing treatment shall be responsible for the treatment and pass all information about the treatment to the company carrying out the post de-icing/anti-icing check.

Note 3: The flight crew shall receive a confirmation from the ground crew that all de-icing/anti-icing operations are complete and that all personnel and equipment are clear before reconfiguring or moving the aircraft.

Next Steps

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Aircraft, aviation, Ground Operations, SAS blogs, Aircraft De-icing, Aircraft Anti-icing, Aviation Flight Operations, Anti Icing Fluids, Aircraft Ground De-icing, Communication Procedures