jt15d ata 73 maint

Pratt & Whitney JT15D Series (CAT C)

ATA 73 – ENGINE FUEL AND CONTROL (MAINTENANCE)

of 14 FOR TRAINING PURPOSES ONLY © JT15D - ISSUE 1, 2009





0 TABLE OF CONTENTS

1 FCU adjustment 3 1.1 Specific Fuel Gravity 3 1.2 Acceleration Check 3 1.3 Ground idle 4 1.4 Flight Idle (JT15D-5 series) 4 1.5 Minimum fuel flow adjustment 5 1.6 Flight idle (JT15D-5 series) 6 2 Flow Divider Cross Manifold Leak Test 7 2.1 Purpose 7 2.2 Procedure 8 3 FCU to FDV Rigging / Idle speed Adjustment 11 3.1 Initial rigging (engine stopped) 11




1 FCU ADJUSTMENT

1.1 Specific Fuel Gravity

Jet A/A1, JP5, JP8 = .81 Jet B, JP4 = .79 AVGAS = .73 NOTE: Only adjust if a full load of different fuel is

used

1.2 Acceleration Check

1 Start engine and set it to idle 2 Find target N1 for the day (refer to airframe chart) 3a Perform slam acceleration from idle to 6% below

target N1 (JT15D-1 and 4 series)

3b Perform slam acceleration from flight idle (52%) to 6% below the target N1 (JT15D-5 series)

4a Ensure acceleration is within 7.5 seconds with ignition OFF and 5.3 seconds with ignition ON (JT15D-1 and 4 series)

4b Ensure acceleration is within 5.0 to 7.5 seconds (JT15D-5 series)

NOTE: The difference in acceleration time is

caused by the step modulator that is energised when the ignition is switched ON (JT15D-1 and 4 series)

NOTE: If adjustment is required, turn ACCEL screw

CW to increase and CCW to decrease NOTE: ¼ turn changes ACCEL time by 0.4 seconds

NOTE: Engine should be stopped when adjustment is made




1.3 Ground Idle

1 Start engine and set idle speed 2a Ensure engine speed is 49% ± 1% N2 for Citation

II, SII, Diamond I and IA (JT15D-1 and 4 series)

2b Ensure engine speed is 46% ± 1% N2 for Citation I (JT15D-1 and 4 series)

2c Ensure engine speed is 46% N2 (JT15D-5 series)

NOTE: If adjustment is required, turn min

governing screw CW to increase CWW to decrease

1.4 Flight Idle (JT15D-5 series)

1 Start engine and set to ground idle (46% N2) 2 Switch flight idle "ON" 3 Ensure N2 is 52% NOTE: If adjustment is required, turn flight idle

solenoid CW to increase and CCW to decrease.




1.5 Minimum fuel flow adjustment

1.5.1 Above 2000 ft

1 Disconnect PY plug from FCU (blue plug) 2 Start engine, stabilise for 3 minutes 3 Record actual N2 speed and pressure altitude 4 Compare with chart in maintenance manual to ensure N2 is within the limits

1.5.2 Below 2000 ft

If adjustment if performed below 2000 ft, vacuum pump must be used to ensure metering valve is against minimum flow stop. NOTE: No bleed or power extraction during

test NOTE: If adjustment is required, turn min

flow screw CW to increase minimum flow speed and CCW to decrease




1.6 Flight Idle (JT15D-5 series)

1 Deploy trim stop 2 Start engine and bring power lever against trim stop 3 Record actual N1 speed and OAT and ensure it is within chart limit NOTE: If adjustment is required, turn max N2 stop screw CCW to

increase and CW to decrease N1 speed NOTE: Stow trim stop after check and adjustments are completed




2 FLOW DIVIDER CROSS MANIFOLD LEAK TEST

2.1 Purpose

The cross manifold leak test allows pinpointing which of the three components (flow divider, fuel nozzles, or automatic shut-off valve) is defective.




2.2 Procedure

1 Remove the secondary fuel line from flow divider outlet. 2 Cap off secondary outlet from flow divider. 3 Start engine and run at idle. 4 Use a clean container and collect fuel that comes out from secondary

inlet tube. 5 If less than 60 CC per minute are collected, replace flow divider. 6 If more than 60 CC per minute are collected, replace O-ring on shut-off

valve and perform cross manifold leak test on fuel nozzles. NOTE: 60 CC equals approximately 2 ounces (

1/4 cup)




3 FCU TO FDV RIGGING / IDLE SPEED ADJUSTMENT

3.1 Initial rigging (engine stopped)

1 Disconnect FCU/FDV interconnecting rod and airframe

power lever cable from FCU arm. 2 Move FCU arm CCW until "pick up point" is found

(spring tension is felt). Mark the position of the "pick up point" on the FCU quadrant (always near the 20° mark on quadrant).

3 With FDV in the idle detent position and FCU arm at the pickup point, adjust interconnecting rod length to align bolt holes.

4 With the FDV in full shutoff position, adjust the FCU minimum stop to provide a gap of .001" to .003". This ensures a positive shutoff position at the FDV.

5 Position FDV in the idle detent position. Move cockpit power lever from cut-off to the idle detent position. Adjust to match and connect power lever cable to FCU arm (ref to airframe maintenance manual).

6 Verify full power lever travel, shutoff stop at FDV, maximum stop at FCU, FDV detent friction adjustment and if necessary lubricate control rod end bearings.

7 Start engine and run it at idle speed. 8 Adjust idle adjustment screw to give recommended

engine idle speed. 9 Shutdown engine.




NOTE: Refer to airframe maintenance manual for

complete procedure.




PAGE INTENTIONALLY LEFT BLANK

jt15d ata 73 maint

Documents

n2 jt15d

flight idle jt15d

jt15d issue

engine fuel

seconds jt15d

series note

ia jt15d

engine speed