Section IV. COLD WEATHER OPERATION

TB 55-1500-334-25

Section IV. COLD WEATHER OPERATION

started and warms, the hydraulic fluid temperature should

4-1. Operating Temperature Limitations.

stabilize within normal operating limits.

a. Although MIL-H-83282 operates well under

4-2 Low Temperature Procedures.

normal temperatures, the viscosity of the fluid increases

as the temperature decreases. Therefore, the following

If, at any time during low temperature

minimum ambient operating temperatures have been

operation, initial flight control movement is sluggish or

established for the use of M I L-H-83282.

stiff, cycling of the flight controls may alleviate the

problem. Agitation of the fluid under pressure and radiant

Aircraft

Minimum Temperature

heat from engines and transmissions may warm MIL-H-

83282 sufficiently to allow satisfactory operation of flight

UH-1

-30F -35C

controls.

OH-58

-25F -32C

CH-47

-50F -46C

b. If the temperature drops below the limitations

OV1

-40F -40C

AH-1

-50F -46C

in para 4-1, and the procedures in para 42A are

CH-54

See note below

unsuccessful, follow procedures given below:

Servicing

Equipment

(1) OH-58A Drain the MIL-H-83282

D5A,D5B,D6

-20F -29C

hydraulic fluid from the flight control system, and service

MSU-1

-25F -32C

with MIL-H-5606.

AF5

-25F -32C

UH-60A

-40F -40C

(2) AH-1G Drain the MIL-H-83282 hydraulic

fluid from hydraulic systems No. 1 and 2, and service

with MIL-H-5606.

NOTE

(3) UH-1 Drain the MIL-H-83282 hydraulic

CH-54B aircraft based in Alaska will

fluid from the hydraulic system(s) and service with MIL-H-

retain MIL-H-5606. All CONUS based

5606.

CH-54 aircraft will be converted to MIL-

H-83282.

(4) CH-47 Drain the MIL-H-83282 hydraulic

fluid from the hydraulic systems and components, and

The above temperatures are outside air temperatures

service with MIL-H-5606.

(OAT), measured at ground level prior to engine start.

(5) OV-1 Drain the MIL-H-83282 hydraulic

b. The above temperature limitations are based

fluid from the hydraulic system, and service with MIL-H-

on a cold soak of the hydraulic fluid at low temperatures.

5606.

Aircraft that are sheltered or preheated prior to engine

start should not have any problems with stiff or sluggish

(6) UH-60A See TM 55-1520-237-23-4.

flight controls. Unless the sheltered areas are at or below

the above temperatures in para 4-1, the viscosity of MIL-

H83282 will not create any difficulty. Once the aircraft is

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