12-33-01
ALL ú ú 01B Page 301 ú Feb 18/00
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL
(5) Holdover time is the approproximate time anti-icing fluid will keep the frost, ice, or snow off the airplane surfaces that have protection.
NOTE: You cannot find the level of protection or the holdover time
____ with precision. The weather conditions and the fluid/fluid mixture will have an effect on the holdover time. The person that does the procedure must use experience to make an estimate of the protection time. When there is precipitation, remove the ice from the airplane as near to the departure time as it is possible.
(6)
Type I (not thickened) deicing/anti-icing fluids usually have a minimum of 80 percent Glycol. The temperature makes the viscosity change but the shear stress does not. These fluids give anti-icing protection for only a short time.
(7)
Type II and Type IV (thickened) deicing/anti-icing fluids usually have a minimum of 50 percent Glycol. There is also 45 to 50 percent water plus thickeners and inhibitors. The temperature and the shear stress that is applied can make the viscosity of these fluids change. They are usually very viscous at low levels of shear stress. When the shear stress increases, their viscosity decreases very quickly. Type II and Type IV fluids give longer holdover times than Type I deicing/anti-icing fluids.
F. An airplane that is parked, for this cold weather procedure, is an airplane in the loading area for a short time to be prepared for the departure. If the airplane stays in the loading area through the night in cold weather conditions, refer to the Guidelines for Parked Airplanes in this procedure. Cold weather operation does not include an airplane that is parked for a long time. This is included in chapter 10.
G. Slush is ice and/or snow that is not fully melted. Thus, the ice removal/anti-icing procedures for ice and snow removal apply to slush. A special procedure for slush is not necessary.
H. Start electronic equipment in the cold weather conditions the same as in the usual conditions. A special procedure is not necessary.
I. The engine start procedure for cold weather operation is given in Chapter 71.
J. The APU start procedure is given in Chapter 49.
TASK 12-33-01-603-001
2. Cold Weather Maintenance Procedure__________________________________
A. References
(1)
AMM 10-11-03/201, Parking in High Winds
(2)
AMM 12-14-01/301, Potable Water System
(3)
AMM 12-17-01/301, Toilet Tank
(4)
AMM 71-00-00/201, Power Plant
B. Equipment
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
12-33-01
ALL ú ú 01B Page 302 ú Oct 18/00
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL
WARNING: MAKE SURE YOU USE THE CORRECT EQUIPMENT FOR THE FLUID YOU USE.
_______ MECHANICAL OR EQUIPMENT SHEAR OF THE FLUID CAN OCCUR IF THE CORRECT EQUIPMENT IS NOT USED. IF THIS OCCURS, THE VISCOSITY OF MANY TYPE II AND TYPE IV FLUIDS WILL DECREASE AND, THUS, THE APPROXIMATE HOLDOVER TIME. MAKE SURE YOU REFER TO THE MANUFACTURER'S GUIDELINES FOR THE FLUID THAT YOU USE.
(1) Ground equipment that is correct and satisfactory to use with the materials that follow:
(a)
Deicing/Anti-icing truck
(b)
Boomtruck or Cherry-picker
(c)
Water
(d)
Type I, II, or Type IV deicing fluid
(e)
Type I, II, or Type IV anti-icing fluid
(f)
Hot air source
C. Consumable Materials
NOTE: The applicable fluids which obey the Boeing document D6-17487,
____ "Certification Test of Airplane Maintenance Material" and conform to any of the following specifications, are acceptable fluids.
(1) Type I (newtonian) Fluids
(a)
G02301 Fluid SAE AMS 1424 latest revision
(b)
G00072 Fluid MIL-A-8243D Types 1 and 2
NOTE: MIL-A-8243D Type 1 fluid is acceptable in a 50/50
____ fluid/water concentration. MIL-A-8243D Type 2 fluid is acceptable in any concentration. There are no holdover time guidelines for MIL-A-8243D fluids.
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