Learjet 60XR Pilots Manual

data may be used by the operator for flight planning. REVISING THE MANUAL Periodically, Numbered Changes may be issued against this manual. Pages included in Numbered Changes supersede like numbered pages in the Pilot’s Manual. Each page of a Numbered Change will contain a “Change” number located at the lower inside margin of the page. Por- tions of the text affected by the change are indicated by a vertical bar at the outer margin of the page. The vertical bars may not appear on pages that contain graphs or tables. Additionally, when a “changed” page oc- curs as the result of a rearrangement of material due to a change on a previous page, no vertical bar will appear. Pilot’s Manual ii PM-133 REVISING THE MANUAL (CONT) The List of Effective Pages provides the user with a guide to establish the current effective date of each page in the Pilot’s Manual and may be used as an instruction sheet for incorporating the latest Numbered Change into the Pilot’s Manual. Information included in the List of Ef- fective Pages states the current “Change” number for each page and the dates of Original issue and Numbered Changes. An asterisk (*) next to a page number indicates the page was changed, added, or deleted by the current change. ADDRESSES Your comments and suggestions concerning this manual are solicited and should be forwarded to: Learjet, Inc. P.O. Box 7707 Wichita, Kansas 67277-7707 Attn: Technical Publications Pilot’s Manual PM-133 I-1 TABLE OF CONTENTS TABLE OF CONTENTS Aircraft General Description.................................................................... 1-1 Airplane Three-View (Figure 1-1)........................................................ 1-2 General Arrangement - Exterior (Figure 1-2) .................................... 1-3 Cabin Entry Door ...................................................................................... 1-5 ENTRY DOOR Light ............................................................................. 1-5 Cabin Door Operation........................................................................... 1-6 Opening Cabin Door (From Outside) (Figure 1-3)....................... 1-6 Closing Cabin Door (From Inside) (Figure 1-4)............................ 1-7 Opening Cabin Door (From Inside) (Figure 1-5).......................... 1-8 Closing Cabin Door (From Outside) (Figure 1-6) ........................ 1-9 Emergency Exit/Baggage Door............................................................. 1-10 AFT CAB DOOR Light........................................................................ 1-10 Emergency Exit/Baggage Door Operation ...................................... 1-10 Emergency Exit/Baggage Door Operation (From Inside) (Figure 1-7).............................................................. 1-11 Emergency Exit/Baggage Door Operation (From Outside) (Figure 1-8)........................................................... 1-12 External Doors ......................................................................................... 1-13 EXT DOORS Light ............................................................................... 1-13 Tailcone Baggage Compartment........................................................ 1-13 Turning Radius (Figure 1-9)................................................................... 1-14 Danger Areas (Figure 1-10) .................................................................... 1-15 Pedestal (Typical) (Figure 1-11) ............................................................. 1-16 Instrument Panel (Typical) (Figure 1-12) ............................................. 1-17 Pilot’s Circuit Breaker Panel Layout (Figure 1-13) ............................. 1-19 Copilot’s Circuit Breaker Panel Layout (Figure 1-14) ........................ 1-21 SECTION I GENERAL DESCRIPTION Pilot’s Manual PM-133 1-1 SECTION I GENERAL DESCRIPTION AIRCRAFT GENERAL DESCRIPTION The Learjet 60XR aircraft, manufactured by Learjet, Inc., is an all metal, pressurized, low-wing, turbofan-powered monoplane. The high-aspect ratio, fully cantilevered, swept-back wings with winglets are of conven- tional riveted construction except for the upper section of the winglets, which is full-depth honeycomb core bonded to the outer skin. The fu- selage is of “area rule” design and semi-monocoque construction. Two inverted “V” ventral fins (delta fins) are fitted to the aft section of the tailcone to provide the aircraft with favorable stall recovery character- istics and additional lateral/directional stability. Thrust is provided by two pod-mounted PW305A turbofan engines manufactured by Pratt and Whitney Canada, Inc. Independent fuel systems supply fuel to the engines with fuel storage available in wing and fuselage tanks. Engine- driven hydraulic pumps supply hydraulic power for braking, extend- ing and retracting the landing gear, wing flaps, and spoilers. The land- ing gear system is a fully retractable tricycle-type gear with dual main- gear wheels, anti-skid braking, and nose-wheel steering. The flight con- trols are manually controlled through cables, bellcranks, pulleys, and push-pull tubes. Lateral and directional trim is accomplished by means of electrically-actuated trim tabs installed on the left aileron and on the rudder. Longitudinal trim is accomplished by changing the angle of in- cidence of the horizontal stabilizer with an electrically-operated linear actuator. Aircraft air conditioning systems provides heating, cooling, and pressurization for the crew, passenger, and cabin baggage com- partments. Pilot’s Manual 1-2 PM-133 AIRPLANE THREE-VIEW Figure 1-1 58 ft 8 in (17.89 m) 56 ft 2 in (17.12 m) 14 ft 7 in (4.44 m) 43 ft 10 in (13.35 m) 8 ft 3 in (2.51 m) 14 ft 8 in (4.48 m) NOTE: All dimensions shown for aircraft in static position. Pilot’s Manual PM-133 1- 3 GENERAL ARRANGEMENT - EXTERIOR Figure 1-2 1. Fwd Avionics Compartment 2. Stall Warning Vane 3. Pitot-Static Tube 4. Lower Cabin Entry Door 5. Upper Cabin Entry Door 6. Inboard Wing Stall Fence 7. Boundary Layer Energizers 8. Outboard Wing Stall Fence 9. Wing Fuel Filler Cap 10. Wing Navigation Light 11. Aft Baggage Compartment Door 12. Tailcone Compartment Access Door 13. Rudder 14. Elevator 15. Tail Navigation Light 16. Tail Strobe/Beacon 17. Recognition Light 18. Ram Air Inlet 19. Fuselage Fuel Cell 20. Flap 21. Spoiler/Spoileron 22. Aileron 23. Emergency Exit/Baggage Door 1-3/1-4 (Blank) Pilot’s Manual PM-133 1 - 5 CABIN ENTRY DOOR The cabin door consists of an upper portion that forms a canopy when open and a lower portion with integral steps. The upper portion has gas-charged struts (gas springs) installed to assist in door opening. A latch, when over centered, retains the door in the open position. A door release handle, located on the aft door frame, mechanically releases the latch to allow the upper door to close. The gas-charged struts soften door opening and closing movements. The lower portion of the door incorporates a torsion bar system to provide closing assistance. Cables attached to take-up reels are installed on the forward and aft lower door structure to aid in closing and prevent damage if the door is inad- vertently allowed to drop open. A self-contained hydraulic damper is also attached to the lower door as an additional protection against dropping the door. Each door half has a locking handle which, when ro- tated, drives a series of locking pins into the fuselage structure and through interlocking arms secure the halves together. When the pins are engaged, the door becomes a rigid structural member. There is a secondary safety latch installation on the lower door separate from the door locking system. This installation will hold the lower door against the door frame seal, and align the locking pins with the pin holes. When the lower door is unlocked, the safety latch will keep the door from fall- ing open. This latch may be operated from either inside or outside the aircraft. A key lock is provided on the upper door to secure the aircraft from the outside. Rotating the key lock will move a locking bar over the inside upper door handle, preventing it from rotating to the open position. ENTRY DOOR LIGHT A red ENTRY DOOR warning light is installed on the glareshield an- nunciator panel to provide the crew with visual indication of cabin door security. The light will illuminate and flash to indicate that one or more of the locking pins is not fully engaged or that the key lock is in the locked position. The light will illuminate steady when the entry door is full open and power is on the aircraft. If all pins are fully en- gaged, and the locking bar is recessed, the most probable cause for illu- mination is a switch malfunction or misalignment. Pilot’s Manual 1-6 PM-133 CABIN DOOR OPERATION To open the cabin door from the outside: 1. Insert key in key lock and rotate. The key lock will retract the upper door handle locking bar. 2. Insert finger in the handle finger pull door and pull out handle halves. Rotate the handle halves clockwise to the stop. 3. Raise upper door to the full open position. 4. Reach inside and rotate lower door locking handle to OPEN position. 5. Release safety catch, located on forward side of middle step, from the inside, or outside using exterior button. 6. Gently lower door to the full down position. OPENING CABIN DOOR (FROM OUTSIDE) Figure 1-3 Pilot’s Manual PM-133 1 - 7 CABIN DOOR OPERATION (CONT) To close cabin door from inside: 1. Raise lower door, using forward cable knob, until safety latch fully engages. 2. Rotate lower door locking handle to the locked position. 3. Release upper door with door release handle on aft door frame. 4. With the upper door locking handle in OPEN position, pull door tightly against door seal and rotate locking handle to the locked position. (If preparing for flight, check ENTRY DOOR warning light extinguished.) CLOSING CABIN DOOR (FROM INSIDE) Figure 1-4 Pilot’s Manual 1-8 PM-133 CABIN DOOR OPERATION (CONT) To open cabin door from the inside: 1. Lift upper door locking handle to the OPEN position. 2. Push upper door outward and up to the full open position. 3. Rotate lower door locking handle to OPEN position. 4. Release safety latch, located on forward side of middle step. 5. Gently lower the lower door to full down position using the for- ward cable knob. OPENING CABIN DOOR (FROM INSIDE) Figure 1-5 Pilot’s Manual PM-133 1 - 9 CABIN DOOR OPERATION (CONT) To close and lock cabin door from the outside: 1. Raise lower door until the safety latch fully engages. 2. Reach inside and rotate lower door locking handle to the locked position. 3. Release upper door with door release handle on aft door frame. 4. With upper door locking handle in the OPEN position, gently lower upper door and push tightly against door frame. 5. Rotate exterior handle halves counterclockwise to the stop and ensure each half recesses into door structure. 6. Insert key in key lock and rotate. This will extend the upper door locking bar over the locking handle. CLOSING CABIN DOOR (FROM OUTSIDE) Figure 1-6 Pilot’s Manual 1-10 PM-133 EMERGENCY EXIT/BAGGAGE DOOR The emergency exit/baggage door, located on the aft right side of the cabin, serves a dual function. It provides egress from the cabin during emergencies and access from the outside to the aft cabin baggage area. The door is attached to the airframe by hinges at the top and secured by locking pins at the side and lower edge. The door structure incorpo- rates a window similar to those installed in the cabin. Gas-charged struts (gas springs) are installed to assist in door opening and closing and to hold the door open when fully extended. For security on the ground, the inner door latching handle has a red streamered locking pin installed through a hole in the handle to restrict movement. This pin must be removed before every flight. AFT CAB DOOR LIGHT To provide cockpit visual indication as to the flight status of the emer- gency exit/baggage door, a red AFT CAB DOOR warning light is in- stalled on the glareshield annunciator panel. The light will illuminate and flash if the locking pins are not fully engaged, the handle mecha- nism is not in the latched position, or the red streamered locking pin has not been removed for flight. The light will illuminate steady when the handle is at the full open position. If all components are found to be properly positioned, a switch malfunction or misalignment is the prob- able cause for illumination. EMERGENCY EXIT/BAGGAGE DOOR OPERATION To open emergency exit/baggage door from the inside: 1. Remove red streamered locking pin. 2. Rotate locking handle to the OPEN position. 3. Push door outward and up to the full open position. To close the emergency exit/baggage door from the inside: 1. With the door locking handle in the OPEN position, gently lower the door. 2. Pull door tight against door seal and rotate the locking handle to the locked position. 3. If preparing for flight, no further action is required except to check AFT CAB DOOR warning light extinguished. If securing door on the ground, rotate pin cover knob and insert red streamered lock- ing pin. Pilot’s Manual PM-133 1 - 11 EMERGENCY EXIT/BAGGAGE DOOR OPERATION (FROM INSIDE) Figure 1-7 Pilot’s Manual 1-12 PM-133 EMERGENCY EXIT/BAGGAGE DOOR OPERATION (CONT’D) To open emergency exit/baggage door from the outside: 1. Insert finger in the handle finger pull door and pull out handle halves. Rotate the handle halves clockwise to the stop. 2. Raise door upward to the full open position. Stand clear if there is a chance the cabin is still pres- surized. EMERGENCY EXIT/BAGGAGE DOOR OPERATION (FROM OUTSIDE) Figure 1-8 To close the emergency exit/baggage door from the outside: 1. With the door locking handle in the OPEN position, gently lower the door and push tightly against door frame. 2. Rotate exterior handle halves counterclockwise to the stop and ensure each half recesses into door structure. 3. If preparing for flight, no further action is required except to check AFT CAB DOOR warning light extinguished. NOTE Pilot’s Manual PM-133 1 - 13 EXTERNAL DOORS External doors are installed to provide for baggage loading and main- tenance access. The nose area forward of the cockpit is accessible through four doors — two on the left side and two on the right side. The tailcone is accessible through the tailcone access door and aft baggage door, both located on the left side. Two doors provide access to the sin- gle-point pressure refueling system. These doors are located side by side on the right side of the fuselage beneath the right engine. Access to the external servicing provisions for the toilet is through a door on the underside of the fuselage below the toilet. EXT DOORS LIGHT Illumination of the red EXT DOORS warning light, located on the glareshield annunciator panel, indicates the tailcone access door and/ or the aft baggage door is not properly closed and latched. The primary purpose of the light is to indicate a door open condition prior to takeoff. If the doors were properly latched prior to takeoff and the light illumi- nates in flight, the most probable cause is a switch failure. TAILCONE BAGGAGE COMPARTMENT The tailcone baggage compartment is accessed through a door located under the left engine pylon. A slight pressure differential (0.25 psi) is maintained to prevent fluids from entering the compartment. The pres- sure is provided by ram air entering the dorsal inlet. An outflow valve, located on the top of the baggage compartment, controls the pressure. Pilot’s Manual 1-14 PM-133 Turning radius expressed above is based upon 60° nose wheel travel (full-authority/low-speed steer- ing). Limited authority steering provides 24° of nose wheel travel. Turning radius will increase accordingly. TURNING RADIUS Figure 1-9 36.5 feet (11.1 meters) 29.3 feet (8.9 meters) N O S E W H E E L W I N G T I P NOTE Pilot’s Manual PM-133 1 - 15 DANGER AREAS Figure 1-10 WEATHER RADAR ENGINE EXHAUST ENGINE INTAKE 240 feet (73.2 m) 75°F (24°C) 1000°F (538°C) Engine danger area shown for takeoff RPM. 35 feet (10.7 m) 35 feet (10.7 m) 2 feet (0.6 m) Pilot’s Manual 1-16 PM-133 PEDESTAL (TYPICAL) Figure 1-11 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 1. Thrust Levers 2. Thrust Reverser Levers 3. APR Switch (Recessed) 4. Flap Switch 5. Check List Switch 6. Copilot Course (CRS) Control 7. Copilot Cursor Control Panel (CCP) 8. Control Display Unit #2 (CDU) 9. Fuel Control Panel 10. Dual HF Comm Control Head 11. AIRSHOW Flight Deck Controller 12. Emergency Exit Lights Control Panel 13. Radio Tuning Unit #2 (RTU) 14. Trim Control Panel 15. Control Display Unit #1 (CDU) 16. Pilot Cursor Control Panel (CCP) 17. Pilot Course (CRS) Control 18. Nose Steer Switch 19. Parking Brake Handle 20. Engine Sync Switches 21. Emergency Brake Handle 22. Spoiler Lever Pilot’s Manual PM-133 1 - 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 1. Pilot’s Switch Panel 2. Pilot’s Audio Control Panel 3. Pilot’s EFIS Control Panel 4. Pilot’s Flight Instruments (PFD & MFD) 5. Pilot’s Display Control Panel (DCP) 6. Electronic Standby Instrument System (ESIS) 7. Flight Control Panel (FCP) 8. Heading Speed Altitude Panel (HSA) 9. Annunciator Panel 10. Fuel Quantity Indicator 11. Copilot’s Display Control Panel (DCP) 12. Copilot’s Flight Instruments (MFD & PFD) 13. Copilot’s EFIS Control Panel 14. Copilot’s Audio Control Panel 15. Copilot’s Switch Panel 16. Cockpit Voice Recorder Control Panel 17. Landing Gear Control Panel 18. Radio Tuning Unit #1 (RTU) 19. Center Switch Panel 20. ELT Control Switch 16-125B 1-17/1-18 (Blank) INSTRUMENT PANEL (TYPICAL) Figure 1-12 Pilot’s Manual PM-133 1 - 19 1-19/1-20 (Blank) PILOT’S CIRCUIT BREAKER PANEL LAYOUT Figure 1-13 L EMER BUS CONT FLOOD LTS WARN LTS NAV LTS L INV EMER BAT 1 L INSTR LTS L EL LTS L AC BUS L DC BUS 1 CENTER PANEL— PED LTS CHART HOLDERS BAT TEMP L DC BUS 2 PRI PITCH TRIM L STALL WARN CABIN PWR BUS L DC BUS 3 ROLL TRIM WHEEL MASTER L GEN L DC BUS 4 YAW TRIM SQUAT SW L IAPS AP 1 PITCH SERVO ROLL-YAW SERVO MACH TRIM L PITOT HEAT L WSHLD DEFOG L NAC HEAT L STALL VANE HEAT L WSHLD DEFOG L ICE DETECT LIGHT FUEL QTY PWR 1 FUS TANK XFR PUMP ICE DETECTOR L STBY —SCAV PUMP L JET PUMP —XFR VALVE L BLEED AIR TEMP CONTROL IND CABIN PRESS IND XFLO VALVE OXYGEN VALVE BLEED AIR OV HT MANUAL TEMP CONTROL L FIRE DETECT L FW SOV COOL CONTROL L FIRE EXT L START AHS 1 PFD 1 MFD 1 L ENG CH A L ENG CH B ADC 1 LO SPD WARN1 L IGN CH A L IGN CH B L CLOCK EFIS CONTROL 1 ENGINE SYNC AUDIO 1 RTU 1 L AVIONICS MASTER L TR CONT L TR AUTO STOW COMM 1 NAV 1 ATC 1 L ENGINE VIB MON ADF 1 DME 1 PFD 1 HEAT DATA LINK RADIO IAPS TEMP HF 1 FDR PHONE GPS 1 XM WEATHER TAWS SATCOM HOT CUP GALLEY DRN WATER HEATER READ LTS AISLE LTS OVEN TOILET TABLE LTS MICRO WAVE CABIN LTS TOILET SERVICE VIDEO STEREO CABIN CABIN AVIONICS AVIONICS INSTRUMENTS L ENGINE FUEL ENVIRONMENT ANTI-ICE AFCS LIGHTS TRIM-FLT CONT ELECTRICAL Denotes DC circuit breakers Denotes AC circuit breakers Denotes circuit breakers on the emergency bus Denotes unused circuit breaker positions EMER BAT 3 L FUEL FLOW L OIL PRESS MFD 1 HEAT FMS DISPLAY 1 DISPLAY CONTROL 1 FSU 1 MFD CONTROL 1 DCU 1 EDC 1 SELCAL RADIO ALT TAWS VANITY DRN Pilot’s Manual PM-133 1 - 21 1-21/1-22 (Blank) COPILOT’S CIRCUIT BREAKER PANEL LAYOUT Figure 1-14 EMER LTS WARN LTS WING INSP LT R EMER BUS CONT EMER BUS TIE BEACON- STROBE LTS R EL LTS R INSTR LTS EMER BAT 2 AC BUS TIE FLASH LTS LOGO LT PULSE RECOG LT R DC BUS 1 DC BUS 1 TIE NOSE STEER R STALL WARN SEC PITCH TRIM R DC BUS 2 DC BUS 2 TIE NOSE STEER SPOILER FLAPS R DC BUS 3 DC BUS 3 TIE RUDDER PEDAL ADJUST SPOILERON TRIM-FLAP -SPOILER IND R DC BUS 4 R INV HYDRAULIC PRESS IND GEAR R AC BUS R GEN AIR PRESS IND ANTI SKID AP 2 R IAPS SYSTEM TEST R NAC HEAT R WSHLD DEFOG R PITOT -STALL- TAT HEAT FUS TANK AUX PUMP FUEL QTY PWR 2 R ICE DETECT LIGHT R WSHLD DEFOG STANDBY PITOT HEAT R JET PUMP -XFR VALVE R STBY -SCAV PUMP STAB HEAT WSHLD HEAT R STALL VANE HEAT WING HEAT ALCOHOL SYSTEM TAT PROBE HEAT R FW SOV R FIRE DETECT CABIN PRESS SYS R BLEED AIR R START R FIRE EXT AUTO TEMP CONT CREW FAN CABIN AIR R ENG CH B R ENG CH A CABIN FAN AUX CABIN HEAT R IGN CH B R IGN CH A MFD 2 PFD 2 AHS 2 ENGINE DIAGNOSTIC SYSTEM LO SPD WARN 2 ADC 2 R TR AUTO STOW R TR CONT EFIS CONTROL 2 R CLOCK STATIC SOURCE R ENGINE VIB MON R AVIONICS MASTER RTU 2 AUDIO 2 MFD 2 HEAT ATC 2 NAV 2 COMM 2 NOSE FAN INSTR PANEL FANS TCAS DME 2 ADF 2 RADAR CVR GPS 2 HF 2 ELT NAV ELT EDC 2 HOUR METER PASS SPKR CABIN DISPLAY CABIN FIRE DETECT AFT BAG LT PASS INFO CABIN AUDIO ENTRY LTS LIGHTS ELECTRICAL Denotes DC circuit breakers Denotes AC circuit breakers HYDRAULICS R ENGINE AFCS ANTI-ICE TRIM-FLT CONT O P E N AVIONICS AVIONICS CABIN CABIN Denotes circuit breakers on the emergency bus Denotes unused circuit breaker positions INSTRUMENTS ENVIRONMENT R OIL PRESS FUEL FSU 2 DISPLAY CONTROL 2 FMS DISPLAY 2 STORM SCOPE DATA LINK AUX CREW HEAT R FUEL FLOW PFD 2 HEAT MFD CONTROL 2 DCU 2 PASS AUDIO PASS CONTROL 220 VAC OUTLETS 110 VAC OUTLETS 110 VAC INV 220 VAC INV Pilot’s Manual PM-133 II-1 TABLE OF CONTENTS Engines........................................................................................................ 2-1 Engine Fuel and Control System ......................................................... 2-1 Engine Control Logic Diagram (Figure 2-1)....................................... 2-2 Thrust Levers.......................................................................................... 2-3 Engine-Driven Fuel Pump.................................................................... 2-3 Hydro-Mechanical Fuel Control Unit ................................................. 2-3 Full Authority Digital Electronic Control (FADEC) ......................... 2-4 ENG CMPTR Switches..................................................................... 2-4 ENG CMPTR Lights ......................................................................... 2-5 Variable Inlet Guide Vanes and Variable Stator Vanes ..................... 2-5 Surge Bleed Control............................................................................... 2-5 Automatic Performance Reserve (APR)................................................. 2-6 APR Switch ............................................................................................. 2-6 APR ARM Indicator .............................................................................. 2-6 APR ON Indicator ................................................................................. 2-7 Engine Synchronizer ................................................................................. 2-7 ENG SYNC Switches ............................................................................. 2-7 ENG SYNC Indicators........................................................................... 2-8 Ground Idle System .................................................................................. 2-8 Engine Oil System ..................................................................................... 2-8 Pressure System ..................................................................................... 2-8 Engine Oil System Schematic (Figure 2-2) ......................................... 2-9 Scavenge System .................................................................................. 2-10 Breather System.................................................................................... 2-10 Engine Ignition System........................................................................... 2-10 IGNITION Switches ............................................................................ 2-11 Ignition Lights ...................................................................................... 2-11 Engine Indicating System (EIS) ............................................................. 2-11 EIS Engine Page (Figure 2-3) .............................................................. 2-11 N1 Indicators......................................................................................... 2-12 ITT Indicators ....................................................................................... 2-12 N 2 Indicators......................................................................................... 2-13 FUEL FLOW (FF) Indicators .............................................................. 2-13 Engine Oil Indicators (Pressure and Temperature) ........................ 2-13 Oil Pressure Lights............................................................................... 2-13 Engine Chip Lights .............................................................................. 2-14 ENG FILTERS Light............................................................................. 2-14 ENG VIB Lights.................................................................................... 2-14 SECTION II ENGINES & FUEL II-2 PM-133 Pilot’s Manual TABLE OF CONTENTS (Cont) Engine Diagnostic System (EDS) ...................................................... 2-14 Engine Diagnostic System (Figure 2-4) ............................................ 2-15 Engine Diagnostic Unit (EDU) ..................................................... 2-16 Isolation Units................................................................................. 2-16 Control Display Unit (CDU) ......................................................... 2-16 EDS FAULT Annunciator .............................................................. 2-16 EDS Record Switch......................................................................... 2-16 Engine Fire Detection System ............................................................... 2-17 SYSTEM TEST Switch — Fire Detection Function ......................... 2-17 ENG FIRE PULL Light ....................................................................... 2-17 Engine Fire Extinguishing System........................................................ 2-18 ENG FIRE PULL Handle and ENG EXT ARMED Lights ............. 2-18 Engine Fire Extinguishing System (Figure 2-5)............................... 2-19 Fire Extinguisher Discharge Indicators ............................................ 2-20 Thrust Reverser System ......................................................................... 2-20 Deploy................................................................................................... 2-21 Stow ....................................................................................................... 2-21 Auto Stow ............................................................................................. 2-22 Thrust Reverser Assembly ................................................................. 2-22 Thrust Reverser System Schematic (Figure 2-6) ............................. 2-23 Thrust Reverser Lever ........................................................................ 2-25 Throttle Balk Solenoid ........................................................................ 2-25 Hydraulic Control Unit (HCU) ......................................................... 2-26 Thrust Reverser Relay Box ................................................................. 2-26 Aircraft Fuel System ............................................................................... 2-27 Wing Tanks ........................................................................................... 2-27 Fuselage Tank....................................................................................... 2-27 Fuel Control Panel Switches and Annunciators ............................. 2-27 Fuel Control Panel (Figure 2-7) ......................................................... 2-28 JET PUMP Switches ....................................................................... 2-28 Fuel System Schematic (Figure 2-8) .................................................. 2-29 STBY PUMP Switches.................................................................... 2-31 XFLO VALVE Switch ..................................................................... 2-31 NORM XFR Switch ........................................................................ 2-32 AUX XFR Switch ............................................................................ 2-33 GRVTY XFR Switch........................................................................ 2-34 FILL Switch ..................................................................................... 2-34 Fuselage Tank Switch Priority ...................................................... 2-35 Fuselage Tank Full Light ............................................................... 2-35 Fuselage Tank Empty Light .......................................................... 2-35 LO FUEL PRESS Lights ................................................................. 2-35 Pilot’s Manual PM-133 II-3 TABLE OF CONTENTS (Cont) Fuel Gaging System............................................................................. 2-36 Fuel Quantity Indicator.................................................................. 2-36 Fuel Quantity Probes...................................................................... 2-36 Total Quantity Indicator (SPPR) ................................................... 2-36 Fuel System Glareshield Lights ......................................................... 2-37 FUEL PRESS Lights ........................................................................ 2-37 LOW FUEL Light ............................................................................ 2-37 FUEL SYS Light............................................................................... 2-37 Ram Air Fuel Vent System.................................................................. 2-38 Single-Point Pressure Refuel (SPPR) System ................................... 2-38 Single-Point Refuel System Schematic (Figure 2-9) ........................ 2-39 WING and FUS PRECHECK Valves............................................ 2-41 SPPR BATT Switch ......................................................................... 2-41 Refuel Selector Switch .................................................................... 2-42 FUS FULL Light .............................................................................. 2-42 VENT OPEN Light ......................................................................... 2-42 Fuel Drains (Figure 2-10) .................................................................... 2-43 Fuel Anti-Icing Additive..................................................................... 2-44 Refueling ............................................................................................... 2-44 Auxiliary Power Unit (APU) ................................................................. 2-45 APU Control Panel .............................................................................. 2-46 APU Control Panel (Figure 2-11) ....................................................... 2-46 APU AMPS Indicator ..................................................................... 2-46 APU FIRE......................................................................................... 2-46 APU FAULT/STOP Switch ........................................................... 2-47 APU RUNNING/START Switch.................................................. 2-47 APU MASTER Switch .................................................................... 2-47 APU ON Indicator .......................................................................... 2-47 APU SYSTEM TEST Switch........................................................... 2-47 APU Relay Panel.................................................................................. 2-48 APU Relay Panel (Figure 2-12) .......................................................... 2-48 FIRE DET BITE Indicator............................................................... 2-48 GEN FAULT BITE Indicator.......................................................... 2-48 FAULT Reset Switch ....................................................................... 2-48 APU BITE Annunciator Box............................................................... 2-49 APU BITE Annunciator Box (Figure 2-13) ....................................... 2-49 APU Generator..................................................................................... 2-49 APU Operating Procedures................................................................ 2-50 APU Pre-Start Check ...................................................................... 2-50 APU Start-Up .................................................................................. 2-50 APU Shutdown ............................................................................... 2-51 APU Shutdown Features (Automatic)......................................... 2-51 Pilot’s Manual PM-133 2-1 ENGINES The Learjet 60XR is powered by two PW305A Pratt and Whitney two- spool, front-fan engines. Each engine is rated at 4600 pounds thrust at sea level. A spinner and an axial-flow fan, located at the forward end of the en- gine, are driven by the low-pressure rotor. The low-pressure rotor con- sists of an axial-flow fan (low-pressure compressor) and a three-stage low-pressure axial turbine, mounted on a common shaft. The high- pressure rotor consists of a high-pressure compressor (four axial stages and a single centrifugal stage) and a two-stage high-pressure axial tur- bine, mounted on a common shaft. The rotor shafts are concentric, so that the low-pressure rotor shaft passes through the high-pressure rotor shaft. The high-pressure rotor drives the accessory gearbox through a driveshaft geared to the N2 rotor shaft. An annular duct serves to bypass fan air for direct thrust and also di- verts a portion of the fan air to the high-pressure compressor. The by- pass ratio (bypass flow to core flow) is 4.55:1. Air from the low-pressure compressor flows through variable inlet guide vanes and first-stage variable stator vanes to the high-pressure compressor and is dis- charged into the annular combustor. Combustion products flow through the high- and low-pressure turbines and are discharged axially through the exhaust duct to provide additional thrust. ENGINE FUEL AND CONTROL SYSTEM The engine fuel and control system pressurizes fuel routed to the en- gine from the aircraft fuel system, meters fuel flow, and delivers atom- ized fuel to the combustion section of the engine. The system also supplies high-pressure motive-flow fuel to the aircraft fuel system for jet pump operation. The major components of the system are the thrust levers, the engine-driven fuel pump, the hydro-mechanical fuel control unit (HFCU), the full authority digital electronic control (FADEC), vari- able inlet guide vanes, variable stator vanes, and the surge bleed control. SECTION II ENGINES & FUEL Pilot’s Manual 2-2 PM-133 ENGINE CONTROL LOGIC DIAGRAM Figure 2-1 N1 P3 N2 T4.5 IGV BOV Servo Pressure Fuel Shutoffs Standby Shutdown Fuel In Pump Metering Valve Torquemotor Valves IGV Position Demand Inlet Flight Conditions Wf Fuel Demand Overspeed Trip Metered Fuel (Wf) 28V DC Power Pilot Select and Aircraft Discretes Engine Trims Cockpit Displays Full Authority Digital Electronic Control (FADEC) Thrust Lever (TLA) Aircraft Air Data Computer Hydro-mechanical Fuel Control Unit (HFCU) Surge Bleed Control Pilot’s Manual PM-133 2 - 3 THRUST LEVERS Two thrust levers (one for each engine) are located on the upper portion of the pedestal, and operate in a conventional manner with the full for- ward position being maximum thrust. Stops at the IDLE position pre- vent inadvertent reduction of the thrust levers to CUT-OFF. The IDLE stops can be released by lifting a finger lift on the outboard side of each thrust lever. Detents are provided for CUT-OFF, IDLE, maximum cruise (MCR), maximum continuous thrust (MCT), takeoff (TO), and auto- matic performance reserve (APR). Each thrust lever is mechanically linked to a rotary variable differential transformer (RVDT) position transducer. The RVDT provides dual electrical signals to the FADEC which correspond to the thrust lever angle (TLA). A switch, which ac- tuates in the CUT-OFF position, provides a discrete signal to the FADEC to initiate the normal shutdown sequence. ENGINE-DRIVEN FUEL PUMP The engine-driven fuel pump provides high-pressure fuel to the engine fuel control system as well as motive-flow fuel for operation of the air- craft jet pumps. The pump consists of a low-pressure pump element, high-pressure pump element, relief valve, and motive flow provisions. The pump itself is housed in the hydro-mechanical fuel control unit. Fuel from the low-pressure element passes through a filter before it en- ters the high-pressure element. In the event the pressure differential across the fuel filter increases to a preset level, the impending bypass indicator will actuate and the white ENG FILTERS light will illuminate. If the pressure differential continues to increase, due to clogging, the fil- ter bypass valve will open to allow fuel to bypass the filter. HYDRO-MECHANICAL FUEL CONTROL UNIT (HFCU) The HFCU mounts to the permanent magnet alternator on the aft side of the accessory gearbox. The HFCU’s main function is to control fuel flow to the engine’s fuel nozzles. Fuel flow is regulated in response to commands from the FADEC which computes the necessary settings for the existing conditions. The HFCU also provides servo pressure to the variable guide vane actuator, houses the engine-driven fuel pump, and provides fuel pressure regulation. Pilot’s Manual 2-4 PM-133 FULL AUTHORITY DIGITAL ELECTRONIC CONTROL (FADEC) There are two FADECs installed, one on each engine. Each FADEC has two channels (A and B), each fully capable of controlling the engine. During normal operation (ENG CMPTR switch in AUTO), the most ca- pable channel is automatically selected to control the engine. FADEC functions include: • Thrust Management • Surge Protection • Overspeed Protection • Fault Detection • Bleed-Off Valve Control • N1 Bug Setting • Automatic Performance Reserve • Engine Synchronization • Inlet Guide Vane & • Starting & Shutdown Inlet Stator Vane Control Control • Igniter Operation • Digital ITT The crew is able to control the engine through the FADEC by changing the TLA input to change desired thrust level. The FADEC receives in- put from several engine sensors and the aircraft’s air data computers and together with the TLA input it determines the appropriate signals to send to the HFCU, the inlet guide vane and stator vane actuator, and the bleed-off valve solenoid to achieve the desired engine operation. The aircraft’s air data computers provide inlet static pressure (PAMB ) and Mach number as primary signals to the FADEC. PAMB and Mach number are also measured by the FADEC transducer but used only as a backup to the air data computer signals. Sensors on the engine pro- vide inlet total temperature (T T0 ) signals to the FADEC. A TT0 signal is provided by the air data computer, but used only as a backup to the en- gine sensor signals. Electrical power is supplied by an engine-driven permanent-magnet alternator. Backup power and power for starting is provided through the ENG CH A and ENG CH B circuit breakers on the pilot’s and copilot’s circuit breaker panels. Backup power is avail- able to channel A during EMER BUS mode. ENG CMPTR SWITCHES Two switches, one for each engine, on the center switch panel labeled ENG CMPTR CH. A/AUTO/CH. B enable the flight crew to select the FADEC channel (A or B) to be used to control the engine. Normally, the switches are left in the AUTO position which allows the FADEC to au- tomatically select the most capable channel. During abnormal situa- tions, the crew may use this switch to force the desired channel to take control of the engine. Pilot’s Manual PM-133 2 - 5 ENG CMPTR LIGHTS Two ENG CMPTR lights are provided for each engine and reside in the annunciator panel. One light is white and one is amber. Illumination of a white light indicates a minor malfunction in one or both channels of the associated FADEC. Illumination of an amber light indicates a major malfunction in one channel of the associated FADEC. Illumination of both the white and amber lights indicates a malfunction in both chan- nels of the associated FADEC. Dispatch is not permitted with any white or amber light illuminated. VARIABLE INLET GUIDE VANES AND VARIABLE STATOR VANES The engine is equipped with variable inlet guide vanes to direct air into the first stage axial compressor and variable stator vanes to direct air into the second stage axial compressor. This feature permits peak com- pressor efficiency throughout various operating conditions. A variable guide vane actuator is used to simultaneously position the guide vanes and stator vanes. The FADEC computes the desired vane position and commands the HFCU to provide servo pressures (fuel) to the actuator which positions the vanes. A rotary variable differential transformer (RVDT) position transducer, mounted on the actuator, sends an electri- cal feedback signal to the FADEC. SURGE BLEED CONTROL Each engine has a surge bleed control system which allows surge free operation throughout various operating conditions and improves en- gine starting characteristics. The system consists of a solenoid control valve and three bleed-off valves (BOV). Two valves bleed compressor air from station 2.5 while the third valve bleeds air from station 2.8. BOV position is controlled by the FADEC via the solenoid control valve. Compressor discharge air (P 3) is used to provide servo pressure to close the bleed-off valves. The solenoid control valve applies P 3 pres- sure to the BOVs to close them and vents P 3 pressure to open them. In the event a solenoid control valve fails, the bleed-off valves will go to the open position. Pilot’s Manual 2-6 PM-133 AUTOMATIC PERFORMANCE RESERVE (APR) The APR system provides for an automatic change from the takeoff N1 rating to the APR rating for the operative engine in the event of loss of thrust from one engine during takeoff. The amount of thrust change will depend on ambient conditions. Since the engines installed on the Learjet 60XR are flat rated, the difference between takeoff and APR thrust will be very small under some ambient conditions. The system consists of an APR switch on the forward pedestal, APR ARM and APR ON indicators which display on the EIS Engine Page normally dis- played on the pilot’s MFD, and associated aircraft wiring. To detect loss of thrust, the FADEC continuously monitors the opposite engine’s N 1 and N 2 signals. Loss of thrust is defined by the FADECs as meeting one or more of the following criteria: • The N 1 of one engine differs more than 15% from the N1 of the oth- er engine. • The N2 of one engine differs more than 7.5% from the N 2 of the other engine. • The N 1 of one engine differs more than 4% from the N 1 of the other engine and N1 is decreasing at a rate greater than 5% per second. • The N 2 of one engine differs more than 2% from the N 2 of the other engine and N2 is decreasing at a rate greater than 2% per second. APR SWITCH APR system automatic operation is pilot controlled through the APR ARM-OFF switch located on the right side of the pedestal adjacent to the thrust levers. The switch is recessed to prevent inadvertent APR ac- tivation. The switch has two positions: OFF and ARM. For automatic operation the switch is set to ARM. When ARM is selected, the APR ARM indicator on the EIS will illuminate provided no faults exist which affect the APR function. When a loss of thrust is detected by one of the FADECs, an uptrim of the operative engine is commanded. The FADEC checks that the change to the appropriate APR N1 setting has been triggered and if it has, the APR ON indicator on the EIS will illu- minate. Should automatic activation of APR fail to occur, APR thrust can be manually obtained by setting the thrust lever to the APR detent. In this case, the APR ON indicator on the EIS will not illuminate. Once invoked, the APR thrust schedule will remain active until the APR switch is set to OFF. APR ARM INDICATOR The green ARM indicator on the EIS will illuminate when the APR switch is in the ARM position provided no faults exist which affect the APR function. Pilot’s Manual PM-133 2 - 7 APR ON INDICATOR If APR is activated automatically by the FADEC, the amber APR ON in- dicator on the EIS will illuminate once APR thrust has been achieved. The APR ON indicator will not illuminate if APR thrust is obtained manually using the thrust lever detent. ENGINE SYNCHRONIZER The engine synchronizer system consists of two ENG SYNC switches, an amber or green SYNC indicator on the EIS Engine Page, and engine synchronizer circuits within the FADECs. During flight, the engine syn- chronizer, if selected, will maintain the two engines’ N1 or N 2 in sync with each other. The engine synchronizer must not be used during takeoff, landing, or single-engine operations. Engine synchronization is not available on the ground or whenever APR is armed. Electrical pow- er for the engine synchronizer is 28 VDC supplied through the ENGINE SYNC circuit breaker on the pilot’s circuit breaker panel. Synchronization is accomplished by maintaining the speed of the slave engine in sync with the speed of the master engine. The master engine is determined and so designated during installation. The following cri- teria must be satisfied before the system will operate: • The ENG SYNC switch is set to SYNC. • The difference between the N 1 speed of each engine is no more than 5%. • Thrust levers are in the range from IDLE to MCT. • Thrust reversers are stowed. • APR is disarmed. Deviating from any of these criteria will cancel engine synchronization. The system will raise flight idle of the master engine by a maximum of 1% N 1 when activated. ENG SYNC SWITCHES Two ENG SYNC switches are installed on the pedestal immediately be- low the thrust levers. The ENG SYNC control switch is labeled SYNC- OFF and the ENG SYNC selector switch is labeled N 1-N 2 . When moved to the SYNC position, the control switch will activate the engine syn- chronizer and remove N 1 Indicator compensation; therefore, the N 1 and N 1 bug presentations will reflect actual N 1 speed. When SYNC is selected, N 1 or N 2 synchronization is selected by moving the ENG SYNC selector switch to N1 or N 2 as desired. Pilot’s Manual 2-8 PM-133 ENG SYNC INDICATORS The green SYNC indicator on the EIS will illuminate when the SYNC- OFF switch is in the SYNC position. The amber SYNC indicator on the EIS and the amber ENG SYNC light on the glareshield will illuminate when the nose gear is not up and the SYNC-OFF switch is in the SYNC position. GROUND IDLE SYSTEM The ground idle system provides reduced engine idle speeds for ground operations. When the thrust lever is in the IDLE detent and the squat switch is in the ground mode, idle speed is reduced from approx- imately 65% N2 (flight idle) to approximately 52% N2 (ground idle). In flight, the idle speed setting is selected to ensure adequate transient re- sponse to full takeoff power. The system incorporates a 10-second delay after touchdown before ground idle is activated. ENGINE OIL SYSTEM The engine oil system provides lubrication and cooling for the main- shaft bearings, all accessory drive gears and all accessory bearings. The system consists of a pressure system, a scavenge system, and a breather system. PRESSURE SYSTEM The oil tank is an integral part of the engine intermediate case. Oil is drawn from the tank by a gear-type pressure pump. Pump output is di- rected through a pressure adjusting valve which bleeds excess pressure back to the pump inlet. From there, oil passes through an oil filter and fuel/oil heat exchanger before being routed to the mainshaft bearings, accessory drive gears, and accessory bearings. A cold-start valve di- verts oil from the pump outlet into the accessory gearbox sump if pres- sure exceeds 200 psi during cold weather operation. The oil filter incorporates a bypass valve allowing oil to bypass the fil- ter should it become clogged. An impending bypass indicator provides both a pop-up type visual indicator and an electrical signal to activate the ENG FILTERS light in the cockpit. To avoid false indications at en- gine start-up with cold oil, a thermal lockout inhibits the impending bypass indication if oil temperature is below 38° C (100° F). Pilot’s Manual PM-133 2 - 9 An anti-siphon device is incorporated to prevent oil from being si- phoned out of the oil tank following engine shutdown. The device con- tains a small hole drilled through to the expansion space at the top of the oil tank. This breaks the siphon action caused by the oil tank level being higher than the main bearing oil jets. ENGINE OIL SYSTEM SCHEMATIC Figure 2-2 L OIL PRESS L ENG FILTERS FUEL/OIL HEAT EXCHANGER L ENG CHIP # 4 Bearing # 3 Bearing # 2 Bearing # 1 Bearing Oil Tank Sump SIPHON BREAK Breather OIL SUPPLY LINE OIL PRESSURE LINE OIL SCAVENGE LINE OIL BYPASS LINE OIL FILTER BYPASS VALVE CHIP DETECTOR IMPENDING BYPASS INDICATOR PRESSURE ADJUSTING VALVE PRESSURE PUMP SCAVENGE PUMP ELECTRICAL COLD START VALVE STRAINER OIL TEMPERATURE SENSOR OIL PRESSURE SENSOR OIL PRESSURE SWITCH Pilot’s Manual 2-10 PM-133 SCAVENGE SYSTEM The scavenge system incorporates three gear-type scavenge pumps in- stalled in the accessory gearbox. Oil from the number 1 and 2 bearing compartments drains by gravity into the accessory gearbox sump. Oil from number 3 and 4 bearings is pumped by scavenge pumps into the accessory gearbox sump. Scavenge flow from all bearing compart- ments is aided by pressurizing airflow through the labyrinth air seals. Bypass valves are incorporated around the number 3 and 4 bearing scavenge pumps to prevent pressure build-up in the scavenge lines at higher bearing cavity pressure conditions. Oil collected in the accessory gearbox sump is pumped to the top of the oil tank by a separate scav- enge pump. BREATHER SYSTEM Air from the bearing compartments, accessory gearbox, and oil tank is vented overboard through an impeller-type centrifugal air/oil separa- tor installed in the accessory gearbox. ENGINE IGNITION SYSTEM Each engine ignition system consists of an IGNITION switch, a green annunciator, two ignition exciter units, two shielded cables, two igniter plugs, and associated aircraft wiring. The ignition exciter unit is a solid- state, high-voltage unit which provides a spark rate of 1 to 4 sparks per second at an output of 24,000 to 35,000 volts. The igniter plugs are mounted at four and five o’clock positions in the combustion chamber case. The plugs are operated by separate cables and spark when pulsed by the ignition exciter units. During the start cycle, the ignition system is automatically energized by the FADEC when the thrust levers are placed in the IDLE position and N 2 is above approximately 6%. The ig- nition system is automatically de-energized by the FADEC at approxi- mately 40% N 2. At pressure altitudes below 20,000 feet and TLA at or above IDLE, the FADEC will sequence the ignition system on should N 2 speed fall below 40%. This feature provides for an immediate relight when the aircraft is below 20,000 feet. The ignition system may be op- erated continuously through the corresponding IGNITION switch. The ignition system light will be illuminated whenever the associated igni- tion system is operating either continuously (IGNITION On) or auto- matically (FADEC control). The ignition system is powered by 28 VDC from the L and R IGN CH A and IGN CH B circuit breakers on the pi- lot’s and copilot’s circuit breaker panels. The ignition system is opera- tive during EMER BUS mode. Pilot’s Manual PM-133 2 - 11 IGNITION SWITCHES The IGNITION switches, located on the center switch panel, are used to obtain continuous engine ignition. The switch controlling the left en- gine ignition system is labeled L-OFF. The switch controlling the right engine ignition system is labeled R-OFF. When an IGNITION switch is placed in the On (L or R as applicable) position, 28 VDC from the cor- responding L or R IGN CH A and IGN CH B circuit breakers is applied to the corresponding ignition exciter units. IGNITION LIGHTS Green lights above each IGNITION switch are installed to indicate ig- nition system operation. The corresponding light will be illuminated when the associated ignition system is operating either continuously (IGNITION On) or automatically (FADEC control). ENGINE INDICATING SYSTEM (EIS) The EIS Engine Page consists of full time displays, normally on the pi- lot’s MFD, of N 1, ITT, N2 , Fuel Flow, Oil Pressure, and Oil Temperature. The EIS Engine Page can be displayed on any Adaptive Flight Display (AFD) by pressing the SYS button on the respective DCP or pressing a line select key (LSK). Unless in reversionary mode, EIS pages normally displayed on the MFDs when selected to a different EIS page will redis- play after 20 seconds. The EIS Engine Page information is also available on the RTU STBY DISPLAY page. EIS ENGINE PAGE Figure 2-3 Pilot’s Manual 2-12 PM-133 N 1 INDICATORS There is a N 1 indicator for each engine. Each indicator utilizes both a digital display and an arc-sweep display with a pointer to indicate N1 . The N 1 pointer shares the same sweep display as the ITT indicator for each engine. The digital display shows the fan speed to the nearest tenth of a percent. Each indicator also has a trapezoid-shaped N 1 bug driven by a signal from the associated FADEC. The N 1 bug represents the speed the engine should achieve given the ambient conditions, thrust lever setting, flap setting, and squat switch position. N1 is an in- dication of engine speed plus compensation. The FADEC takes into consideration its inputs to calculate and transmit the proper N1 bug set- tings for the ambient conditions. While airborne with the flaps up, the N 1 bugs will show the proper N1 for the selected throttle detent or, if the throttles are in between detents, the next higher setting. While on the ground, or inflight with flaps 3° or lower, the N 1 bugs will show takeoff power. On the ground with the thrust reversers deployed, the N 1 bugs will show the maximum reverse N1 for the current conditions. Each engine FADEC has an externally mounted trim plug which pro- vides trim compensation to the N 1 signal. This trim plug will ensure consistent N 1 indications for a specific paired throttle position. When ENG SYNC is On, compensation is removed. Each engine is also equipped with two induction-type speed sensors at the aft end of the low-pressure rotor. A toothed wheel is attached to the low-pressure shaft rotating adjacent to the stationary speed sensors. As the toothed wheel turns, its teeth cause the frequency output of the speed sensors to change proportionally. The frequency of the output signal represents the speed of the rotating N1 group. One sensor provides output signals to the N1 indicator, and channel A of the FADEC while the other sensor provides output signals to channel B of the FADEC and the opposite engine’s FADEC (used for APR and engine synchronizer). ITT INDICATORS There is an ITT indicator for each engine. Each indicator utilizes digital display and an arc-sweep display with a pointer to indicate ITT. The ITT pointer shares the same sweep display as the N1 indicator for each engine. The digital display shows the turbine temperature to the near- est degree. Interstage turbine temperature for each engine is sensed by Chromel-Alumel parallel wired thermocouples positioned between the high- and low-pressure turbine sections at engine station 4.5. The ther- mocouples provide an average T4.5 signal to the FADEC. The ITT indi- cator is driven by a signal from the FADEC.