4-5. OH-58 T63-A-720 Engine Compressor
Health Cheek Procedures.
a. General Information. The following pro-
cedures are to be used as a troubleshooting aid
in determining compressor health when an en-
gine fails the health check. A baseline is re-
quired with this procedure. Recommend that the
initial compressor health check baseline be performed
concurrent with the establishment of the next re-
quired hit baseline. New compressor health check
baseline will have to be established if the N
Do not operate engine above idle
speed with gage installed or
damage to gage will result.
Ensure engine de-ice and bleed air
heater are off prior to performing
b. Compressor Health Check Procedure:
fitting designed to accommodate a 0-30 PSI pressure
gage (figures 4-5 thru 4-6). Gage needs to withstand
(2) Start engine and stabilize at ground idle
(62-64 percent N
(3) Record air pressure reading (ap-
proximately 15-16 psi for OH-58A/C).
(4) Compare gage reading with baseline
(a) Readings 1 to 2 psi low indicate a
slightly dirty or eroded compressor.
(b) Reading 1 1/2 to 3 1/2 psi low indi-
cate a dirty or eroded compressor.
(c) Reading 3 1/2 psi or lower, check
for compressor air leak or possible compressor
c. This check should be performed on a 500 hour
interval and the results annotated on the 2408-15,
historical record for the aircraft, along with
and replace with a locally manufactured line with a tee
Subcomponents of P.C Gage Test Kit
Item Name and
Elbow, Tube to Hose 3
Adapter, Straight Tube 3
Hose, Nonmetallic 5 ft.
Tee, Tube 1
Coupling, Pipe 4
Adapter, Straight 1
Gage, Pressure 1
*Quantity Required for Each End- Item/System
Figure 4-5. Subcomponents of PC. Gage Test Kit.
cating system or the aircraft rigging has been
changed or if a different gage is used.
(1) Remove line from scroll to ezternal P
the N1 speed and the part and serial numbers of the