Flashcards in Drive System Deck (101):
Primary function of the drive system
To transmit torque from the engines to the proprotors
Secondary functions of the drive system
1. Provides synchronization of the proprotors and single engine operation of the proprotor system through the Interconnect Drive System (ICDS)2. Provides a drive for electrical, pneumatic, and hydraulic power generation.
Proprotor Gearbox - Transmit power and provide a speed reduction from the engine to the proprotor mast
PRGB Overrunning Clutch
Transmits engine torque during normal operation and permits overrunning during single engine operation, autorotation, or if engine speeds are not matched
Total reduction of PRGB
Reduces 15,000 RPM engine input speed to 397 RPM (100% Nr) at the proprotor shaft
Pressure regulating bypass valve in PRGB Lubrication System
Protects the system by returning excess high pressure oil back to the inlet side of the pump
How many debris sensors are there on each PRGB and where are they located?
3; No. 1 sensor is on the air/oil separator, No. 2 sensor is on the front of each PRGB, No. 3 sensor is below the air/oil separator
What provides cooling for the PRGB lubrication system
Nacelle heat exchangers. Airflow through the heat exchangers is provided by the TAGB driven blowers
Nacelle heat exchanger thermostatic bypass valve
Directs a percentage of oil flow around the heat exchanger when oil temperature is below approx. 82 degrees C
Emergency Lubrication System - Provides automatic backup lubrication to either PRGB in the event of a primary lubrication system failure to allow the postponement of an otherwise immediate requirement for landing.
When is the ELS activated? When is it deactivated?
Any time primary lubrication pressure drops below 30 psi. it is deactivated if pressure fluctuates back up to 35 psi or more
ELS has capability to supply oil at a reduced rate for___. How should timing be managed in the event ELS is operated?
30 min. Timing should commense at first indication of PRGB PRESS LOST and should be maintained without interruption until landing and shutdown regardless of whether there is a temporary suspension of ELS.
Functions of the TAGB
1. Change the angle of drive2. Transmit power from the same side PRGB to the MWGB3. Reduce input shaft speed to the ICDS
TAGB gear reduction
Reduces 11,905 RPM input shaft speed to 6574 RPM output to the interconnecting drive shafts
During single engine operations the additional stress placed on operating side TAGB will result in ___
increased oil temperature
5 components mounted on and driven by the TAGB accessory section
1. Generator 2. Gearbox oil pump3. Dual-stage oil filter assembly4. Hydraulic Pump5. Nacelle Blower Driveshaft
How many debris sensors are in the TAGB and where are they located
2; No. 1 is on the sump and No. 2 is on the air/oil separator
What provides cooling for the TAGB lubrication system
Nacelle heat exchangers
Midwing Gearbox - Multiple output unit that transmits power between the left and right interconnect driveshafts without changing speed or direction of rotation.
What components are mounted on and interact with the MWGB
APU, Rotor Positioning Unit (RPU), and rotor brake
Which way do the proprotors turn?
The right proprotor turns clockwise as seen from the aft of the aircraft and the left proprotor turns counterclockwise
what causes the proprotors to turn in opposite directions
An extra idler gear in the first stage gear train of the left PRGB causes the left proprotor to turn counterclockwise.
Major Components of the drive system
1. Proprotor gearbox (PRGB)2. Pylon support assembly 3. Tilt axis gearbox (TAGB) 4. Interconnect Drive System (ICDS)5. Midwing gearbox (MWGB)
Input Quill Assembly
Mounted on the lower aft portion of the PRGB. Provides the forward engine mount where the engine output shaft drives the first stage input gear train through an overrunning clutch.
Pylon Driveshaft Quill
The pylon driveshaft is connected to the pylon driveshaft quill and connects the PRGB to the TAGB.
Allows overrunning during single engine operation, autorotation, or if engine speeds are not matched. During single engine operations, it disengages the PRGB from the failed engine allowing the input quill to freewheel
Nacelle Heat Exchanger
Divided into 3 sections which provide oil/hydraulic fluid cooling for: The PRGB, TAGB/Generator, Hydraulic Pump
Drive System Interface Unit - located in the midwing forward equipment shelf.
Functions of the DSIU
1. Monitors for oil debris in PRGBs, TAGBs, and MWGB and reports all debris to the MCs2. Monitors and controls the ELS and reports ELS status to MCs.
What automatically occurs when the DSIU detects debris on PRGB, TAGB, or MWGB sensors
The DSIU automatically initiates up to 3 attempts to electrically burn off the debris
How many debris sensors are in the TAGB
What activates the ELS
When should ELS endurance timing be commenced
At the first indication of PRGB PRESS LOST and should be maintained without interruption until landing and shutdown.
Pylon Support Assembly
Primary load bearing structure between the wings and nacelles and functions as a pivot point for converting the nacelles
During single engine operation the additional stress placed on the operating engine side TAGB will result in ____
increased oil temperature
Difference in high temperature warning limit on the TAGB during single engine operations
121 degrees C during single engine operations versus 132 degrees C during normal operations
Difference in low pressure warning limit on the TAGB during single engine operations
50 psi versus 30 psi during normal operations
With respect to generators the left TAGB drives ___ and the right TAGB drives ____
left drives VFG No. 3right drives CFG No. 2
With respect to hydraulic pumps the left TAGB drives ___ and the right TAGB drives
left drives No. 1 Hydraulic System pumpright drives No. 2 Hydraulic System pump
Interconnect Drive System - Purpose is to synchronize the proprotors and transfer power between the proprotor systems and all accessory equipment which also enables single engine operation.
1. Pylon driveshaft2. Nacelle blower driveshaft3. Interconnecting driveshafts4. Coupling support assemblies
ICDS Pylon driveshaft
Transfers torque between the PRGB and TAGB
ICDS Nacelle blower driveshaft
Transfers power from the TAGB to the nacelle heat exchanger blower
ICDS Interconnecting driveshafts
5 interconnecting driveshafts that connect the TAGB to the MWGB.
ICDS Coupling support assemblies
(4) located in each wing to provide attachment points that stabilize the 5 driveshafts of the ICDS. Each has vibration/temperature transducers that are monitored by the Vibration Structural Life and Engine Diagnostic (VSLED) system.
What drives the MWGB
Either the APU or the ICDS
When does the ICDS drive the MWGB
When Nr is 84% or greater the ICDS powers the MWGB and the APU is disengaged
What is not being driven when the APU is powering the MWGB
The No. 4 VFG
What accessories are mounted on and driven by the MWGB
1. No. 1 CFG2. No. 3 Hydraulic Pump3. No. 4 VFG4. Shaft driven compressor
Electrically controlled, hydraulically operated unit mounted on the MWGB that is designed to stop the proprotors from 40% Nr in 12 seconds, and from 100% Nr in case of an emergency in 20 seconds
Rotor Positioning Unit - Used to position the rotor blades during the blade fold cycle.
When does the MWGB bypass valve kick in
if differential pressure reaches 142 psi
How many debris sensors does the MWGB have
Oil Cooler and Fan Assembly
located on the aft section of the MWGB that has 4 cores and provides cooled oil for: MWGB/No. 1 CFG, No. 3 Hydraulic pump, No. 4 VFG, and the Shaft Driven Compressor.
Delay takeoff until gearbox oil temperatures reach____
20 degrees C
Indicates PRGB failure and ELS has failed to activate
What triggers PRGB or TAGB warnings
Low oil pressure in the respective system and/or high oil temperature sufficient to indicate an impending catastrophic failure of the PRGB or TAGB
Single engine with an ICDS failure is unrecoverable below ___
170 to 175 KCAS
What triggers ICDS warnings
When proprotor azimuth sensors detect that the proprotors are not synchronized
How should the crew respond to sustained RPM LOW condition indicated
Slow control inputs and monitor Qm as there may be insufficient power to maintain Nr resulting in a severely degraded condition
FCCs detect that Nr has dropped below 80.9% in APLN mode or below 94.7% in VTOL/CONV mode
What triggers L/R PRGB HOT Caution
PRGB temperature is greater than or equal to 110 degrees C
What triggers L/R PRGB PRESS CRIT HI Caution
PRGB oil pressure is greater than 150 psi
L/R PRGB PRESS LOST Caution
PRGB is indicating low oil pressure with both engines operating satisfactorily and the ELS on
What triggers the L/R PRGB PRESS LOST Caution
When primary PRGB lubrication is lost (less than 30 psi) but the ELS is providing supplemental lubrication.
What triggers the L/R PRGB PRESS LOW Caution
PRGB oil pressure between 30 to 60 psi normal operations, or 50 to 60 psi with single engine operations
What triggers the L/R PRGB PRESS HIGH Advisory
PRGB Oil pressure between 95 to 150 psi
___is not available with PRGB oil pressure invalid and subsequent loss of PRGB oil pressure could result in ___
ELS; catastrophic failure in as little as 2 minutes
Failure of the DSIU will affect the availability of ____
ELS and Debris sensors, therefore you will also get an EMERGENCY LUBE FAIL Caution and CHIP DETECTOR FAIL Advisory
Loss of ELS function with subsequent PRGB PRESS LOST dictates ____
an immediate landing
EMERG LUBE HEAT FAIL Advisory
Indicates that an ELS wing heater has failed and the system oil temperature is less than -7 degrees C
What triggers the L/R TAGB HOT Caution
TAGB oil temperature greater than or equal to 110 degrees C
What triggers the L/R TAGB PRESS CRIT HI Caution
TAGB oil pressure is greater than 150 psi
What else will you lose with a Right TAGB PRESS LOST
CFG No. 2
What triggers a L/R TAGB PRESS LOST Caution
TAGB oil pressure less than 30 psi with both engines operating
What triggers a L/R TAGB PRESS LOW OEI Caution
TAGB oil pressure between 50 and 60 psi with only one engine operative
What triggers L/R TAGB PRESS HIGH Advisory
TAGB oil pressure is between 95 and 150 psi
What triggers L/R TAGB PRESS LOW Advisory
TAGB low oil pressure between 30 and 60 psi
What triggers MWGB HOT Caution
MWGB oil temperature at or above 110 degrees C. There will not be a Warning if temperature increases to the warning range of 132 degrees C, but landing criteria changes from land as soon as practical to land as soon as possible
What triggers MWGB PRESS CRIT HI Caution
MWGB oil pressure above 100 psi
MWGB is designed to run without oil at minimum loads for
What triggers MWGB PRESS LOST Caution
MWGB oil pressure is less than 25 psi
What triggers MWGB PRESS HIGH Advisory
MWGB oil pressure between 65 and 100 psi
What triggers MWGB PRESS LOW Advisory
MWGB oil pressure between 25 and 40 psi
Purpose of the ICDS
To synchronize the proprotors and transfer power between the proprotor systems and all accessory equipment.
Nacelle Blower Driveshaft
transfers power from the TAGB to the nacelle heat exchanger blower
Transfers torque between the PRGB and TAGB
How many Interconnecting driveshafts are there
Purpose of the MWGB
To transmit power between the left and right sides of the ICDS without changing speed or direction of rotation.
The MWGB is driven by
Either the APU or ICDS
When can the rotor brake be operated
Only when the ECLs are in the OFF position
What happens to the ECLs when the rotor brake is ON
ECLs are mechanically blocked from movement past the CRANK position
PRGB/TAGB Oil Pressure Limitations
Above 150 psi - High Warning95 to 150 psi - High Caution60 to 95 psi - Normal30 to 60 psi - Low Caution (Both Engines)50 to 60 psi - Low Caution (Single Engine)Below 30 psi - Low Warning (Both Engines)Below 50 psi - Low Warning (Single Engine)
MWGB Oil Pressure Limitation
Above 100 psi - High Warning65 to 100 psi - High Caution40 to 65 psi - Normal25 to 40 psi - Low CautionBelow 25 psi - Low Warning
PRGB/TAGB Oil Temperature Limitation
Above 132 degrees C - High Warning (Both Engines)Above 121 degrees C - High Warning (Single Engine)110 to 132 degrees C - High Caution (Both Engines)110 to 121 degrees C - High Caution (Single Engine)20 to 110 degrees C - NormalBelow 20 degrees C - Low Caution
MWGB Oil Temperature Limitation
Above 132 degrees C - High Warning 110 to 132 degrees C - High Caution 20 to 110 degrees C - NormalBelow 20 degrees C - Low Caution
When will ICDS Failure Warning Post when ICDS is intact
triple Nr sensor failure on one side
30 minutes of PRGB operation with only ELS lubrication is predicated on __
Minimum Qe on the effected engine. Up to 29% in APLN and 62% in VTOL/CONV
What do you lose with an inoperative DSIU
All chip detectors and the ELS
What is the result of a NAC BLOWER FAIL Caution and what pilot action should be taken
fluid temperatures in the affected nacelle will rise rapidly while in VTOL/CONV. Transitioning to APLN will provide sufficient cooling airflow.