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757 MAINTENANCE MANUAL
b) Use suitable covers on the wheels and brakes when operationally feasible.
c) Apply the parking brake to reduce incidental contamination of brake friction surfaces when operationally feasible.
NOTE: The brakes do not need to be re-applied if the _
____ wheels have not rotated since the last brake application.
2) Manually remove snow or ice accumulation from the wheels, brakes or tires. A hot air blower may be used for this purpose.
(f) Landing Gear and Doors
1) Make sure there is not a layer of ice and/or snow on the movable parts and the position indication switches for the landing gear. This could prevent the correct operation of the landing gear. Make sure you do not remove lubricants or make the lubricants thinner when you apply deicing/anti-icing fluids. Parts that are not lubricated can seize or not operate without the correct servicing.
2) Remove the ice and snow from these areas:
a) The landing gear doors
b) The door latches
c) The uplock mechanism
d) The uplock hook
e) The downlock mechanism
f) The bungee springs
g) The lock actuators
h) The position indication switches
3) It is the airline's decision to apply or not apply anti-icing fluid as protection after the ice is removed. 4) Make sure that ice did not collect on the steering cables for the nose wheel. Remove the ice if it is necessary.
5) Examine the alternate extend system for ice that has collected in these areas that are open and not heated: a) The actuators that unlock the landing gear and doors
during alternate extension b) The external mechanism for the landing gear.
CAUTION: DO NOT MOVE THE AIRPLANE IF THE TIRES FREEZE TO THE
_______ GROUND. MAKE SURE THE WHEELS TURN WHEN YOU MOVE THE AIRPLANE.
6) Remove the ice and snow from the ground areas around the landing gear. This will make it less possible that the tires will freeze to the ground. This will also prevent unwanted airplane movement because of the wind or engine operation. a) Use warm air or deicing fluid to release the tires from
the ground or to remove frozen material.
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b) Salt is not recommended since it can collect on the metal parts and cause corrosion.
(g) Wing Fuel Tanks 1) Frost can occur on the bottom of the wings in the fuel tank areas in temperatures above freezing. This is caused by the condensation of moisture in the air when it touches cold surfaces that are below freezing. The frost will usually melt when you add fuel that is a higher temperature. If the frost continues and is more than 1/8 inch thick, remove it before the takeoff. 2) Clear ice can occur on the top of the wing when these conditions occur: a) The temperature of the fuel in the tank is below freezing b) The ambient temperature is above freezing c) There is rain, drizzle or fog.
3) Carefully examine the top of the wing to see if there is clear ice. Use the equipment that is necessary to get sufficient access to the top of the wing to do this check. It is possible that the clear ice can only be found by touch. You must remove clear ice and anti-ice the wing, if it is necessary, before the takeoff.
(h) Miscellaneous 1) Pitot Probe, Static Ports, and Total Air Temperature (TAT) Probes (Fig. 303) a) Look for ice that is attached to the surface 4 feet or less from the pitot inlets, static port, and TAT probe inlets. Remove all the ice in these areas. b) Do not point a spray of deicing/anti-icing fluid directly at or into the pitot inlets, static ports, or the TAT probes. c) If ice causes a blackage of the static openings, carefully apply warm air until the ice melts. d) If you applied too much fluid to the fuselage near the static ports, examine the nearest in-line drain. Remove the water if it is collected there. 2) Drains a) Examine all of the waste water and condensate drains on the airplane to make sure there are no blockages because of ice or other material. It is not necessary to put a plug on the drains during the ice removal or anti-icing procedure. But, do not point a fluid spray at these drain areas. 3) Angle-of-Attack Sensor (Fig. 303) 4) Make sure that no ice and/or snow is on the sensors. Make sure the sensors are free to move. Apply deicing fluid if it is necessary.
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