chapter 73 engine fuel and control - extra aircraftfuel pressure low orifice in engine fuel pressure...

CHAPTER 73PAGE 1

EXTRASERVICE MANUAL EXTRA 300L

PAGE DATE: 4. June 2009

Chapter 73

Engine Fuel and Control

CHAPTER 73PAGE 2



Table of Contents

Chapter Title

73-20-00 CONTROLLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373-20-10 Throttle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373-20-11 Throttle Control Cable . . . . . . . . . . . . . . . . . . . . . . . . . 473-20-12 Rear Throttle Control Lever . . . . . . . . . . . . . . . . . . . . . 673-20-12 Front Throttle Control Lever . . . . . . . . . . . . . . . . . . . . . 873-20-20 Mixture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 873-20-21 Mixture Vernier Control Cable . . . . . . . . . . . . . . . . . . . 9

73-30-00 INDICATING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1373-30-10 Fuel Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1373-30-11 Fuel Pressure Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . 1473-30-12 Sense Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1473-30-15 Engine Fitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

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73-20-00 CONTROLLING

73-20-10 Throttle

Refer to Figure 1. The throttle is controlled by means of thethrottle control levers located in the left side of the cockpit.These levers are interconnected by the throttle controllinkage. The throttle control levers transfer their movementsto the throttle by means of the throttle control cable. Thiscable is routed on the left side of the fuselage, penetrates thefirewall and is then routed centrally below the exhaustmuffler to the throttle. In the engine compartment this cableis covered with a fire sleeve. The cable is attached to thefuselage using clamp blocks at its ends, self-clinching plasticstraps in the cockpit area, and a cushioned clamp at theexhaust muffler. The clamp blocks serve also as a means forrigging. The fire wall penetration is sealed with PRC-812(Products Research & Chemical Corp., USA) firewall sealantand covered with clamp sheets.

Figure 1,Throttle Control

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73-20-11 Throttle Control Cable

Removal

1 Ensure master switch is off.

2 Remove engine cowling per Chapter 71.

3 Remove main fuselage cover per Chapter 53.

4 Remove cotter pin, castle nut, washers and bolt fromthe rod end (2, Figure 4) to throttle actuator (1)attachment.

5 Loosen counter nut and remove the rod end from thethrottle control cable.

6 Remove rod end counter nut and throttle control cablerubber parts.

7 Remove clamp block (3) attachment bolt.

8 Remove clamp block from the throttle control cable.

9 Remove cushioned clamp (4) and self-clinching plasticstraps in engine compartment.

10 Cut wires and remove fire sleeve from the throttlecontrol cable.

11 Remove clamp sheets from the firewall.

12 Mark throttle control cable routing and remove theattachment self-clinching plastic straps in the cockpitarea.

13 Remove cotter pin, castle nut, washers and bolt andremove the rod end (6, Figure 3) from the throttlecontrol lever (5).

14 Loosen counter nut and remove the rod end from thethrottle control cable.

15 Remove rod end counter nut and throttle control cablerubber parts.


17 Remove clamp block from the throttle control cable (8).

18 Pull complete throttle control cable aft to remove fromaircraft. Secure clamp sheets.

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Installation

Install in reverse sequence of removal observing the followingitems:

1 Thread the respective clamp sheet on the throttle controlcable before penetrating the firewall.

2 Install both rod ends with 8 rotations to the throttlecontrol cable. Ensure thread is visible in the inspectionhole. Apply inspection lacquer on the counter nut.

3 Ensure distance between clamp sheet and clamp blockis 705 mm (refer to Figure 2).

Figure 2,Firesleeve Length

4 Renew the sealing of the bushing grooves and gaps atthe engine side of the firewall. Use PRC-812 (ProductsResearch & Chemical Corp., USA) firewall sealant. Letthe sealant slightly cure before thightening the clampsheet attachment bolts. This will strengthen the clamping.

5 Tighten the castle nuts slightly. Ensure movability oflevers.

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73-20-12 Rear Throttle Control Lever

Figure 3,Throttle Control Levers

Removal




4 Remove cotter pin, castle nut, washers and bolt andremove the control cable rod end (6, Figure 3) and thethrottle control linkage (3) from the throttle controllever (5).

5 Pull the smoke switch out of the throttle lever handle.

6 Disconnect smoke switch wiring.

7 Remove intercom switch attachment nut.

8 Remove throttle control lever attachment bolt (7) andremove throttle control lever. Thread the intercomswitch through the throttle control lever.

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Installation


1 Thread the intercom switch and the smoke switch wiringthrough the throttle control lever (5, Figure 3) beforepositioning it.

2 Tighten the throttle control lever castle nut (7) slightly.Ensure movability of levers (1 & 5).

Rigging

1 Bring throttle control lever (5, Figure 3) in a positionparallel to the adjoining fuselage structure steel tube.

2 Check the travel stop at the throttle is reached.

3 If not, loosen the attachment bolt of the front clampblock (3, Figure 4) and adjust the vernier control cableposition in the clamp block.

Figure 4,Throttle Control Cable Rigging

4 Fasten clamp block attachment bolt.

5 Check full travel. In the rearmost throttle control leverposition the residual travel shall be 8 mm.

6 If necessary adjust rod end (2) by the following steps:

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a Remove cotter pin, castle nut, washers and bolt fromthe rod end to throttle actuator (1) attachment.

b Loosen the counter nut and adjust rod end by turning.Ensure thread is visible in the inspection hole whenfastening. Apply inspection lacquer on the counter nut.

c Reinstall the rod end to the throttle actuator (1).

73-20-12 Front Throttle Control Lever

Removal/Installation




4 Disconnect the throttle control linkage (3, Figure 3) fromthe front throttle control lever (1).

5 Disconnect the throttle control handle (2) from the frontthrottle control lever (1).

6 Remove front throttle control lever attachment bolt (9)and remove throttle control lever.

7 Install in reverse sequence of removal. Tighten thethrottle control lever castle (9) nut slightly. Ensuremovability of levers.

73-20-20 Mixture

Refer to Figure 5. The mixture is controlled by means of themixture vernier control cable located on the left side of thecockpit. This cable is routed on the left side of the fuselage,penetrates the firewall and is then routed to the mixer. In theengine compartment this cable is covered with a fire sleeve.The cable is attached to the fuselage using a clamp block atits front end and self-clinching plastic straps in the cockpitarea. The clamp block serves also as a means for rigging. Thefire wall penetration is sealed with PRC-812 (ProductsResearch & Chemical Corp., USA) firewall sealant andcovered with a clamp sheet.

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Figure 5,Mixture Control

73-20-21 Mixture Vernier Control Cable

Removal



3 Remove main and bottom fuselage cover per Chapter53.

4 Remove cotter pin, castle nut, washers and bolt fromthe rod end (2, Figure 7) to mixer actuator attachment(3).

5 Loosen counter nut and remove the rod end (2) fromthe mixture control cable.

6 Remove rod end counter nut and mixture vernier controlcable rubber parts.


8 Remove clamp block (1) from the mixture verniercontrol cable.

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9 Remove clamp sheet attachment bolts on the firewalland remove plastic grommets.

11 Mark mixture vernier control cable routing and removethe attachment self-clinching plastic straps.

12 Remove attachment nut and washer of the mixturecontrol unit.

13 Pull the vernier control unit aft (about 15 cm) and theninside the cockpit to remove.

14 Pull complete mixture vernier control cable aft toremove from aircraft. Secure clamp sheets.

Installation


1 Thread the respective clamp sheet on the mixture controlcable before penetrating the firewall.

2 Install rod end with 8 rotations to the mixture verniercontrol cable. Ensure thread is visible in the inspectionhole. Apply inspection lacquer on the counter nut.

3 Renew the sealing of the bushing grooves and gaps atthe engine side of the firewall. Use PRC-812 (ProductsResearch & Chemical Corp., USA) firewall sealant.

5 Tighten the castle nut slightly. Ensure movability ofactuator 3, Figure 7).

Rigging

1 Bring mixture control knob to the foremost position.

2 Check that the travel stop is reached, and if the gap (seeFigure 6) between mixture control knob and unit is 5mm (tolerance +/-1 mm).

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Figure 6,Gap on Mixture Control Unit

3 If not, loosen clamp block (1, Figure 7) attachment boltand adjust the mixture vernier control cable position inthe clamp block.

4 Fasten clamp block (1) attachment bolt.

Figure 7,Mixture Vernier Control Cable Rigging

5 Check full travel.

6 If necessary adjust rod end (2) by the following steps:

a Remove cotter pin, castle nut, washers and bolt fromthe rod (2) end to mixer actuator (3) attachment.

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b Loosen the counter nut and adjust rod end (2) by turning.Ensure thread is visible in the inspection hole whenfastening. Apply inspection lacquer on the counter nut.

c Reinstall the rod end (2) to the mixture actuator (3).

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73-30-00 INDICATING

Fuel pressure is sensed on the EXTRA 300L engine and isindicated to the pilot in command.

Trouble Shooting

Trouble Possible Cause Remedy

No fuel pressure indication Gauge defective Replace gauge

Fuel pressure low Orifice in engine fuelpressure fitting defective Clean fittingSense line leakage Replace sense line

73-30-10 Fuel Pressure

The fuel pressure gauge is located in the rear instrumentpanel. The instrument takes fuel pressure from the wet line(refer to Figure 8.) and because the fuel flow to the enginecylinders is restricted, there is a direct relation between fuelpressure and fuel flow.

Figure 8,Fuel Pressure Wet Line

CHAPTER 73PAGE 14



73-30-11 Fuel Pressure Gauge


Refer to Chapter 31.

73-30-12 Sense Line


1 Remove cowling per Chapter 71.

2 Remove clamps.

3 Disconnect the sense line from the fitting.

4 Remove the sense line.

5 Install in reverse sequence of removal. Torque sense linefittings with 15.3 – 16.9Nm (135-150lbs-inch) and applyinspection lacquer.

73-30-15 Engine Fitting


1 Remove cowling per Chapter 71

2 Disconnect the sense wet line.

3 Remove the fitting.

chapter 73 engine fuel and control - extra aircraftfuel pressure low orifice in engine fuel pressure...

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