CSP-HE/HS-1
ROTORCRAFT FLIGHT MANUAL
Handling, Servicing,
and Maintenance
MD 500
(Models 369HE/HS/HM
)
Revision 6
7-18
7-20. ENGINE COMPRESSOR WASH
Water wash provisions are incorporated in current configuration helicopters
(Ref. Figure 7−4).
Engine compressor cleaning should be performed by qualified personnel in ac−
cordance with the HMI and the Engine Operation and Maintenance Manual.
The following information is provided for pilots assisting qualified personnel in
the cleaning process.
The starter−generator can be used to motor the Allison 250 Series engine
for compressor cleaning cycle.
Input voltage should be 24 vdc, but it is permissible to use 12 vdc.
To prevent starter−generator damage, duty cycle (cranking) time limits that
must not be exceeded are:
24 vdc External
Auxiliary Power
24 vdc Helicopter
Battery Power
25 Seconds ON
30 Seconds ON
30 Seconds OFF
2 Minutes OFF
25 Seconds ON
30 Seconds ON
30 Seconds OFF
2 Minutes OFF
25 Seconds ON
30 Seconds ON
30 Minutes OFF
30 Minutes OFF
12 vdc External Auxiliary Power
2 Minutes ON
30 Minutes OFF
2 Minutes ON
NOTE
:
Current required by starter-generator to maintain10 percent N
1
rpm should be
approximately 150 amperes with 12 vdc input.
