TM 55-1520-240-23-1
1-86
COLD ENVIRONMENT MAINTENANCE
(Continued)
1-86
If closed, vent valves on rotary-wing
blade shock absorbers must be open
at temperatures below 0ºF (-18ºC).
Dangerous ground and flight reactions
can result.
NOTE
Vent valve may be open or closed at
temperatures between 0ºF (-18ºC)
and 30ºF (-1ºC).
4.
Open vent valves on rotary-wing shock absorbers
(Task 5-93).
5.
Wipe exposed pistons of rotor system
shock absorbers and pivoting and swiveling
servocylinders (Task 1-78). This prevents
accumulation of ice and dirt which damages
seals and packings. Use cloth (E120) damp with
hydraulic fluid (E197).
6.
Follow cold weather maintenance procedures for
utility hydraulic system accumulator (Task 1-65).
7.
Follow cold weather maintenance procedures for
windshields as described:
Do not scrape ice or frost from
windshields. Surface will be
scratched. Do not use wipers before
heating windshield. Scratches or
damaged wipers will result.
a.
Soften ice and frost by operating windshield
heater before using wipers.
8.
Maintain exterior surfaces covered with ice and
snow as follows:
Do not chip or scrape ice or frost from
any helicopter surface. Surface will
be damaged.
a.
Brush all loose snow or frost from helicopter
surfaces. Pay special attention to rotor
blades.
Anti-icing and deicing-defrosting fluid
(E74) is toxic. It can irritate skin and
cause burns. Avoid inhaling. Use
only with adequate ventilation. Avoid
contact with skin, eyes, or clothing.
In case of contact, immediately flush
skin or eyes with water for at least
15 minutes. Get medical attention
for eyes.
Fluid (E74) must be mixed with water.
Strong solutions can damage painted
surfaces.
NOTE
Fluid (E74) will not damage fiberglass
surfaces.
b.
Remove remaining ice. Use anti-icing and
deicing defrosting fluid (E74) diluted as
shown. Work from upper surfaces downward.
NOTE
Fluid (E74) can be heated to 150ºF
(66ºC).
Ambient Temp
Fluid (E74)
Water
30ºF(-0ºC)
20%
80%
20ºF(-7ºC)
30%
70%
10ºF(-12ºC)
40%
60%
0ºF(-18ºC)
45%
55%
-10ºF(-23ºC)
50%
50%
-20ºF(-29ºC)
55%
45%
-30ºF(-35ºC)
60%
40%
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