Forward Fuselage Ice Accretion De-Icing

TASK 12-31-12-660-008-A
Forward Fuselage Ice Accretion De-Icing

WARNING: WEAR A SAFETY HARNESS WHEN YOU DO THE ANTI-ICING/DE-ICING PROCEDURES ON THE FORWARD FUSELAGE WITH THE ENGINES AT IDLE. THE SUCTION AND EXHAUST OF THE ENGINES CAN BE DANGEROUS.

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

WARNING: BE CAREFUL WHEN YOU USE ANTI-ICING AND DE-ICING MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND THE LOCAL REGULATIONS. MAKE SURE THAT THERE IS A GOOD FLOW OF AIR THROUGH THE WORK AREA. DO NOT BREATHE THE FUMES. USE PROTECTIVE CLOTHING, GOGGLES AND GLOVES. IF YOU GET ONE OF THESE MATERIALS:

ON YOUR SKIN OR IN YOUR EYES, FLUSH IT AWAY WITH A FLOW OF CLEAN WATER.
IN YOUR MOUTH, GET IMMEDIATE MEDICAL AID.

CAUTION: DO NOT USE JET EXHAUST TO REMOVE SNOW OR ICE FROM THE AIRFRAME. THE HIGH PRESSURE AND HIGH TEMPERATURE OF JET EXHAUST CAN CAUSE DAMAGE TO THE AIRCRAFT.

CAUTION: DO NOT USE HIGH-PRESSURE JETS OR VAPOR TO DO THE ANTI-ICING/ DE-ICING PROCEDURE. THIS TYPE OF EQUIPMENT CAN PUT FLUID IN PARTS, AND CAN CAUSE DAMAGE TO EQUIPMENT, SPECIALLY TO:

ELECTRICAL EQUIPMENT SUCH AS HARNESSES, PROXIMITY SENSORS AND CONNECTORS (WITH SHORT CIRCUITS OR INCORRECT INDICATIONS AS A RESULT)
EQUIPMENT SUCH AS GEAR BOX SEALS, STEADY BEARINGS, ROTARY ACTUATORS AND UNIVERSAL JOINTS.

HIGH PRESSURE JETS CAN PUSH LIQUIDS INTO BEARINGS, JOINTS, BRAKES, ELECTRICAL CONNECTORS AND OTHER SEALED COMPONENTS. LIQUIDS THAT GET INTO THESE AREAS CAN CAUSE CORROSION, FREEZE DURING AIRCRAFT FLIGHT, REMOVE NECESSARY LUBRICANTS OR START INCORRECT ELECTRICAL FUNCTIONS.

CAUTION: THE ANTI-ICING/DE-ICING MATERIAL HOLDOVER-TIME CAN DECREASE.THIS CAN OCCUR IN ONE (OR MORE) OF THESE CONDITIONS:

LOW TEMPERATURE
HEAVY PRECIPITATION
HEAVY MOISTURE
HIGH WIND SPEEDS
JET BLASTS
AN AIRCRAFT SKIN TEMPERATURE OF LESS THAN THE OAT.

CAUTION: DO THIS TASK IN A LOCATION WITH SUFFICIENT DRAINAGE FOR THE ANTI-ICING/DE-ICING FLUIDS OR MOVE THE AIRCRAFT BEFORE THE ENGINE START. THE ANTI-ICING/DE-ICING FLUIDS CAN MAKE A POOL UNDER THE ENGINE AIR INTAKE. THIS CAN CAUSE THE ANTI-ICING/DE-ICING MATERIALS TO GO INTO THE ENGINE AND PREVENT ITS CORRECT OPERATION.

1. Reason for the Job
This procedure gives guidelines for the removal of ice, frost, slush or snow (from the radome and the forward fuselage area in front of the pitot probes, the static probes and the Angle-of-Attack (AOA) sensors) immediately before departure of the aircraft (crew on board, doors closed, engines at idle, aircraft prepared for the taxiing for take-off).
It is not applicable for other areas of the aircraft.

NOTE: On the ground, in specified meteorological conditions (very low temperatures and snow fall), melted snow from the windshield can freeze again on the sides and lower part of the forward fuselage.
The ice or snow accretion can cause incorrect indications on the related cockpit instruments.

NOTE: The source of all the data related to the fluids must be the manufacturer's recommendations for application and holdover times (supplied with the fluid).
The ice protection procedures and all the data related to de-icing/anti-icing fluids are given in the SAE standards available on the website www.sae.org:

SAE AS 6285 (Aircraft Ground De-Icing/Anti-Icing Processes).
SAE AS 6286 (Training and Qualification Program for De-Icing/Anti-Icing of Aircraft on the Ground).

NOTE: The data given in this procedure are guidelines only.
These guidelines and their experience and knowledge of the local weather conditions help the operators to make correct decisions.
It is the responsibility of the operators to make the decision about the applicable protection procedures.

NOTE: The protection time against new snow/ice accretion will be shorter in very bad weather conditions. Thus, it is important to do this procedure as near as possible to departure of the aircraft.
If a high wind or jet blast occurs, the protection time will be much shorter.
The protection time can also be much shorter if the wind temperature is lower than the Outside Air Temperature (OAT).

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	SPRAYING EQUIPMENT

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.07AAA1)	Deicing Fluid-- Type I Glycol Based

C. Referenced Information

REFERENCE	DESIGNATION
TASK 12-31-00-600-001-A	Cold-Weather Maintenance Procedures

3. Job Set-up
Subtask 12-31-12-660-078-A

A. De-Icing General Information
(1) Refer to (Ref. AMM TASK 12-31-00-600-001) for:

The definition
The cold weather procedures
The de-icing and anti-icing guidelines
The materials that you can use
The general information on effects of icing
The de-icing and/or anti-icing equipment and materials.

Subtask 12-31-12-860-057-A

B. Aircraft Configuration
(1) Make sure that:

The engines are at idle
The pilots have their hands off the throttles and controls.

Subtask 12-31-12-941-061-A

CAUTION: DO NOT MAKE THE ANTI-ICING/DE-ICING FLUID IN TANKS HOT TOO MANY TIMES OR FOR LONG PERIODS. IF YOU DO, THE QUANTITY OF WATER IN THE FLUID WILL DECREASE AND THERE WILL BE A POSSIBLE DEGRADATION OF THE FLUID PERFORMANCE.

CAUTION: BEFORE YOU APPLY ANTI-ICING/DE-ICING FLUIDS, MAKE SURE THAT THE SUPPLY PRESSURE IS NOT MORE THAN THE SPECIFIED VALUES.

C. De-Icing Equipment Configuration

NOTE: Refer to AC 5-9-0 for aircraft de-iced areas.

(1) Prepare the SPRAYING EQUIPMENT and the de-icing solution with Deicing Fluid-- Type I Glycol Based (Material No.07AAA1) .

Minimum dilution: 50%.

(2) Set the de-icing solution temperature to the maximum 90 deg.C (194.00 deg.F).

NOTE: The temperature of the de-icing solution must be as high as possible (but not more than the maximum temperature) to make the removal of the ice faster.

(3) Set the pressure of the SPRAYING EQUIPMENT at low pressure, to less than 1.5 psi (0.1034 bar) impact pressure.

4. Procedure
Subtask 12-31-12-660-069-A

A. Radome and Forward Fuselage De-icing

CAUTION: FOR THIS SPECIAL PROCEDURE, MAKE SURE THAT YOU POINT THE SPRAYING EQUIPMENT NOZZLE FROM THE REAR TO THE FRONT OF THE AIRCRAFT. IF YOU DO NOT OBEY THIS PRECAUTION, THERE IS A RISK THAT THE DE-ICING FLUID WILL GO INTO THE PITOT PROBES.

CAUTION: DURING THE DE-ICING AND CLEANING PROCEDURES, MAKE SURE THAT THE HOT WATER OR HOT WATER/FLUID MIXTURES DO NOT CAUSE THE TEMPERATURE OF THE AIRCRAFT SKIN TO INCREASE TO MORE THAN +70°C. DO NOT USE STEAM. IF YOU DO NOT OBEY THESE PRECAUTIONS, YOU CAN CAUSE DAMAGE TO THE SURFACE OR TO PARTS.

(1) De-icing solution application
Apply the de-icing solution on all the ice or snow accretion.
Point the de-icing equipment nozzle from the rear to the front at a distance between 0.5 m (1.64 ft.) and 3 m (9.84 ft.) from the aircraft skin and forward of the pitot probes and the static probes.

NOTE: This is a special procedure to make sure that the fluid does not go into the pitot and static probes.

Do not apply de-icing fluid on:

The static probes,
The pitot probes,
The inlet and outlet of the avionics-compartment ventilation system.

Subtask 12-31-12-210-061-A

B. Inspection after De-Icing
(1) Make sure that there is no ice, frost, slush or snow on:

The radome and the forward fuselage, specially in front of the pitot probes, the static probes and the AOA sensors,
The ice detectors (if installed),
The AOA sensors,
The pitot probes,
The static probes,
The temperature sensor,
The inlet and outlet of the avionics-compartment ventilation system.

(2) Make sure that there is no remaining de-icing solution on:

The ice detectors (if installed),
The AOA sensors,
The pitot probes,
The static probes,
The temperature sensor.

5. Close-up
Subtask 12-31-12-942-059-A

A. Remove all the tools and equipment used during this procedure.

Subtask 12-31-12-942-060-A

B. Tell the pilots that the de-icing procedure is complete (no ice, frost, slush or snow on the radome and the forward fuselage, specially in front of the pitot probes, the static probes and the AOA sensors) and move away from the aircraft.

[Rev.8 from Aug 2017] 2026.04.02 06:10:33 UTC