TM 55-1520-240-23-3
4-2.1
ESTABLISH HIT BASELINE
4-2.1
INITIAL SETUP
Applicable Configurations:
Without 74
Tools:
None
Materials:
None
Personnel Required:
Inspector
Army Rotary Wing Aviator (2)
References:
TM 55-1520-240-MTF
TM 55-1520-240-T
Equipment Condition:
Battery Connected (Task 1-39)
NOTE
A new baseline Health Indicator Test
(HIT) is required following replacement
of a major engine component that
affects airflow/performance (such as a
hot end).
1.
Face aircraft into wind and turnoff all bleed air.
Insure that PTIT temperatures have stabilized.
2.
Adjust engine not being HIT checked to
GROUND.
3.
Trim rotor speed to 100 percent.
4.
Enter line 1 at FAT nearest free air temperature.
5.
Set N1 percent at value indicated in line 2.
6.
Allow indicated PTIT to stabilize for 2 minutes
while maintaining rotor speed set in step 3 above.
7.
Read PTIT from indicator.
8.
Apply — PTIT A correction factor in line 3 to
indicated PTIT and record result in open space
in line 4.
9.
Apply — PTIT B correction factors in line 5 to
PTIT in line 4 and record result in line 8 for
corresponding columns.
10.
Enter baseline information in the respective
columns of the HIT PTIT LOG (4-2).
11.
Enter aircraft or engine hours and word
"BASELINE" in log section at bottom of HIT PTIT
LOG (4-2).
4-14
