12-33-01
 ALL  ú ú 02B Page 305 ú Jun 10/97
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
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A
747-400
MAINTENANCE MANUAL

_______WARNING:  PERSONS MUST STAY CLEAR OF THE DANGER AREAS IN FRONT OF THE APU INLET
AND IN BACK OF THE APU EXHAUST WHEN IT OPERATES.  THE DANGER ZONE 
GIVEN IN CHAPTER 10 MUST BE OBEYED. 

APU CAN OPERATE WHEN DEICING BUT OBEY THE PRECAUTIONS.
WARNING:PERSONS MUST STAY CLEAR OF THE DANGER AREAS IN FRONT OF THE ENGINE
INLET AND IN BACK OF THE ENGINE EXHAUST WHEN THE ENGINE OPERATES.
THE DANGER ZONE GIVEN IN CHAPTER 10 MUST BE OBEYED.
DO NOT OPERATE ENGINES WHILE DEICING IF POSSIBLE.
IF THE ENGINE MUST OPERATE WHILE DEICING, OBEY THE PRECAUTIONS.
DO NOT RELEASE THE AIRPLANE FOR TAKEOFF WITH ICE, SNOW OR FROST ON THE CONTROL OR WING OR HORIZONTAL TAIL SURFACES EXCEPT FOR A MAXIMUM OF 1/8-INCH FROST ON THE LOWER WING SURFACE BETWEEN THE SPARS.
FUSELAGE AND VERTICAL TAIL SURFACES MUST BE FREE FROM ICE AND SNOW. THIN HOAR FROST IS PERMITTED ON THE TOP OF THE FUSELAGE.
DO NOT POINT THE SPRAY OF DEICING/ANTI-ICING FLUID DIRECTLY INTO THE ENGINE OR APU INLETS, EXHAUSTS, ENGINE THRUST REVERSERS, PROBE INLETS, SCOOPS, VENTS DRAINS, ETC.
DO NOT POINT THE SPRAY OF HOT FLUID DIRECTLY ON THE WINDOWS WHEN THEY ARE COLD.
DO NOT PUSH ICE OR SNOW INTO THE OPENINGS AROUND THE FLIGHT CONTROL SURFACES DURING THE REMOVAL PROCEDURE.
DO NOT CLOSE A DOOR UNTIL YOU REMOVE ALL OF THE ICE OR SNOW WITH DEICING FLUID.
CLOSE THE VALVES FOR THE AIR CONDITIONING PACKS AND BLEED VALVES IF THE ENGINES OR THE APU WILL OPERATE.
OPERATE ALL OF THE CONTROL SURFACES THROUGH THEIR FULL CYCLE. USE A PERSON ON THE GROUND TO MAKE SURE THE CONTROL SURFACES MOVE FULL TRAVEL. IF YOU THINK THAT SEALS ARE FROZEN OR THERE ARE BLOCKAGES, THEN MOVE THE CONTROL SURFACES MANUALLY BEFORE YOU APPLY POWER.
MAKE SURE THE PITOT AND STATIC OPENINGS ARE FREE OF BLOCKAGES AT LEAST 4 FEET AWAY.
MAKE SURE THERE IS NO ICE, SNOW OR SLUSH COLLECTED ON THE LANDING GEAR OR IN THE WHEEL WELL AREA.
MAKE SURE THAT ALL THE INLETS AND EXHAUSTS ARE NOT BLOCKED.
MAKE SURE THAT ALL THE DRAINS ARE CLEAR AND NOT BLOCKED.
MAKE SURE THE ANGLE OF AIRFLOW SENSORS ARE CLEAR OF ICE AND/OR SNOW AND THAT THE SENSORS MOVE FREELY.
APU
ENGINES
PRECAUTIONS
INSPECTION FOR OPERATION
Guidelines Summary: Ice, Snow or Frost Conditions
Figure 301 (Sheet 2)

EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 12-33-01
 ALL  ú ú 02B Page 306 ú Jun 10/97
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
G34355
A
747-400
MAINTENANCE MANUAL

 CAUTION:_______ DO NOT POINT A SOLID FLOW OF FLUID DIRECTLY AT THE
 SURFACE.  APPLY THE FLUID AT A LOW ANGLE TO PREVENT DAMAGE
 TO THE AIRPLANE SURFACES.  DO NOT USE A HIGH PRESSURE

 SPRAY TO BLOW THE ICE AND SNOW OFF THE AIRPLANE SURFACES.
 (d)  
For the best results in the ice or snow removal, you must increase the temperature of the deicing fluid and hot water to 180-200°F, at the tank. A fine to medium spray is recommended to apply the fluid across a large area of ice or snow. This will cause the ice or snow to melt the fastest. A solid flow of fluid is recommended to flush the ice or snow from the airplane surfaces. Make sure the maximum force of the solid flow of fluid on the surfaces is not more than 10 psi on an area of 25 square inches. This will prevent damage to the surfaces.

 (e)  
To find the quantity of deicing/anti-icing fluid to use in the deicing mixture at a given temperature, refer to the airline procedure or the manufacturer's specifications for the fluid you use. For Type I fluids use Fig. 302 in this document. For Type II and Type IV fluids also use Fig. 302. The lower of the ambient temperature or the temperature of the airplane surface is the temperature to use for the Table. See if the mixture of melted ice or snow and deicing/anti-icing fluid freezes again on the airplane as it flows off. If it does, a larger quantity of deicing/anti-icing fluid in the mixture is necessary.

 (f)  
A layer of anti-icing fluid will give protection from ice, snow, and frost if you apply the fluid to a dry wing. A mixture of anti-icing fluid and water (the ambient temperature will have an effect on when to use a mixture with water) will also give protection if you apply it to a dry wing. The fluid must be applied before the conditions start. Use the conditions that follow to make a decision to apply anti-icing fluid fluid to a cold-soaked airplane. 1) There is precipitation. 2) The air temperature is above freezing.
　
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