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Section 3034               GROUND TESTING ENGINES

A. WARM-UP (Cont'd)

11. Operate airspeed blow-out pump individually on each airspeed to ascertain that all lines are clear and that pump is satisfactory. Caution: Do not operate pump while changing blow-out selector switch as damage to the instrument is likely to result.

12. All instrument lights and rheostats shall be turned ON and checked by raising and lowering the intensity of the lights.

13. The electrical instrument circuit switch shall be turned off and the zero position on all instruments checked to make certain that the instruments return to open circuit position.

14. The throttles shall be operated so as to cause a difference of approximately 2 inches of manifold pressure between the two engines and the manifold pressure gauge cross-over valve operated. The action of the manifold pressure gauge in moving from the normal position to the cross-over position or to either one of the bleed positions shall be noted for sluggish or sticking manifold pressure gauges. Return corss-over [[cross-over]] manifold pressure valve to Normal Engine and Instrument.

15. The suction gauge selector valve shall be operated and vacuum checked for following readings:

Turn and Bank 2" ± 2/10"
Directional Gyro & Horizon 4" ± 1/2"

GR -1820 G-102

16. With crossfeed valve off, turn left engine tank selector valve off. Operate engines until fuel pressure on left engine drops and warning lights come on. Turn on crossfeed valve. Pressure should immediately return to normal and warning light should go out. Turn right engine tank selector valve to each individual tank which contains gasoline for a period long enough to definetly [[definitely]] establish that the fuel flow from each tank is O.K. When right engine tank selector is placed in the "off" position both engine fuel pressures should drop off and warning lights for both engines will come on.

R-1830-92

As there is no crossfeed valve on airplanes in this group, the check of the system consists essentially of turning right & left engine tank selector valves to each individual tank containing gasoline for a period long enough to definitely establish that the fuel flow from each tank is O.K. When each tank selector valve is turned to the "off" position, the fuel pressure to the respective engine should drop off and the warning light should come on. Return the right engine selector to "Left Main Tank" to resume normal operation.

                                                   DC--3 GROUND OPERATION
1/15/46                                                            Page 8