Systems 01 Flashcards
(146 cards)
1
Q
A red ________ annunciator indicates a situation that could result in personal injury or loss of life and normally requires immediate attention.
A
warning
Warning lights are critical for pilot awareness and safety.
2
Q
In section ____, there is a chart of the main annunciator panel which relates illumination of a warning/caution light to section I and section III of TO 1T-1A-1.
A
3
This section provides essential information for understanding annunciator responses.
3
Q
After the annunciator that caused the illumination of the master warning or master caution switchlight is identified, the crew should ______ the appropriate master warning or master caution switchlight.
A
reset
Resetting is crucial for clearing warnings after addressing the issue.
4
Q
To cancel a flashing MASTER CAUTION or MASTER WARNING switchlight, ________ switchlight.
A
press the
This action is necessary to acknowledge and clear the warning.
5
Q
Aural warnings in the T-1A may or may not be ___________, include tones and bell sounds, and include voice warnings.
A
silenced
Aural alerts are vital for situational awareness during flight.
6
Q
The annunciators on the ___________ are designed to keep important information in the pilot’s direct field of view.
A
shroud panel
The shroud panel enhances pilot awareness by displaying critical alerts.
7
Q
Fan is connected to the fan turbine by a shaft running __________ impeller shaft.
A
through the center of a hollow
This design is crucial for efficient engine operation.
8
Q
The speed of the engine fan is displayed by the _____ gauge.
A
N1
N1 indicates the speed of the low-pressure turbine and fan.
9
Q
Bypass airflow provides most of the engine thrust at ______ altitudes.
A
low
Understanding thrust generation is important for flight performance.
10
Q
The ________________________ must be functioning for an engine to operate.
A
hydromechanical metering unit (HMU)
The HMU is critical for fuel metering and engine control.
11
Q
The engines will not run unless the ________________ is working.
A
hydromechanical metering unit (HMU)
The HMU’s failure directly affects engine operation.
12
Q
The engine vibration indicator assists in reporting ________ engine vibration.
A
excessive
Monitoring vibration is key for engine health assessment.
13
Q
The engine vibration indicator displays the ________ of vibration in both engines.
A
excessive
Excessive vibration can indicate mechanical issues.
14
Q
Used oil is collected and returned to the oil pump by _____________ on each engine.
A
scavenger pumps
Scavenger pumps are essential for maintaining oil circulation.
15
Q
Oil is cooled by _______________ with aircraft fuel.
A
fuel oil heat exchanger
This system ensures optimal engine temperature management.
16
Q
During engine failure or fire on takeoff, you should not secure the engine until reaching _______ AGL, or clear of obstructions.
A
400
This altitude ensures safety during emergency procedures.
17
Q
Failure of the left engine with synchronization ON could result in a rollback of up to _____ N1 in the right engine.
A
1.5%
Engine synchronization is critical for maintaining balanced flight.
18
Q
If the ENG FIRE PUSH switchlight goes out after retarding the throttle to idle due to an engine fire indication during flight, you should assume there is an ___________________.
A
engine fire. continue boldface procedures.
Adhering to procedures is vital in emergency situations.
19
Q
Pressing the guarded LH ENG FIRE PUSH switch closes the _____ and ___________ system valves.
A
left fuel / hydraulic
This action is necessary to prevent further fuel and hydraulic flow.
20
Q
If engine failure is accompanied by a loud bang and zero N2, _____________ a restart.
A
do not attempt
Safety protocols dictate avoiding restart attempts in this scenario.
21
Q
The crew chief reports a flame in the left engine tailpipe on start. At the same time, you see the LH ENG FIRE PUSH switchlight. You should accomplish the procedures for ________.
A
engine fire during ground operations
Immediate action is required to handle ground fire situations.
22
Q
Oil bypasses the filter to continue lubricating the engine if the oil filter has become ________ with contaminants.
A
clogged
This mechanism is crucial for ensuring engine lubrication continuity.
23
Q
The fire extinguisher agent __________ is a mild ____________, it displaces ____________ air, and it should be avoided by the crew.
A
HALON narcotic breathable
HALON is effective for extinguishing fires but poses inhalation risks.
24
Q
The right fire bottle can be used in _____ engine.
A
either
This flexibility is important for fire suppression strategies.
25
The fire extinguisher agent in a single bottle is fired into an engine all at once when the _______ switchlight is pressed.
bottle discharge button (BOT ARMED PUSH)
## Footnote
Proper activation is essential for effective fire suppression.
26
The engine fire sensing system senses __________ caused by fire or high temperatures caused by an overheat.
excess heat
## Footnote
Heat detection is critical for early fire warning.
27
After retarding the throttle to idle due to illumination of the LH ENG FIRE PUSH switchlight, the LH ENG FIRE PUSH switchlight goes out. The crew should ________.
test fire circuit (for burnouts)
## Footnote
Testing the circuit helps ensure the fire detection system is operational.
28
With electronic fuel control (EFC) OFF, do not attempt to turn the EFC ON with the throttle above the _________ position.
NORM T.O
## Footnote
Adhering to throttle limits prevents engine issues.
29
With electronic fuel control failure, move the throttle of the affected engine slowly in order to avoid ________.
compressor stall / flameout
## Footnote
Careful throttle management is critical in this scenario.
30
If the electronic fuel control fails, expect some _______ and slower engine acceleration.
loss of thrust
## Footnote
Understanding thrust loss is essential for flight safety.
31
Flight with the electronic fuel control off can result in carbon build up (coking) on the ________.
fuel nozzles
## Footnote
Regular checks are necessary to maintain fuel system integrity.
32
The electronic fuel control provides a refinement of the fuel control signals to the ______________.
hydromechanical metering unit
## Footnote
This refinement improves engine performance.
33
The engine ignition system provides a source of ignition for recovery from engine flameout, icing condition problems, and ____________ problems.
stall attitude
## Footnote
The ignition system is critical for maintaining engine operation during challenging conditions.
34
After takeoff, when ignition is not required, the ignition switches should be set to the ________ position.
STBY
## Footnote
This setting conserves resources while keeping systems ready.
35
Ignition switches should be placed to the _______ position for takeoffs, landings, and approaches.
ON
## Footnote
Ensuring ignition is active during critical phases of flight is essential.
36
With the ignition switches in _______ position, the igniters fire automatically when the AOA system detects an approach to stall condition (and ENGINE anti-ice on).
STBY
## Footnote
This automatic function enhances safety during flight.
37
The engine synchronization system uses the ________ engine as the master.
left
## Footnote
Synchronization helps maintain balanced performance between engines.
38
The engines can be synchronized to either ______ or _______ speed.
N1 N2
## Footnote
Synchronization is crucial for reducing engine noise and improving efficiency.
39
Engine synchronization should not be used during ______ and ________.
TO landing
## Footnote
Avoiding synchronization during critical phases ensures safety.
40
To confirm the stall warning system is functioning correctly, use the MASTER TEST switch on the ______________.
overhead panel
## Footnote
Regular testing of the stall warning system is essential for safety.
41
What drives the oil pump?
the accessory gear bx
## Footnote
Understanding the oil pump mechanism is vital for engine lubrication.
42
What returns excess oil to the pump?
pressure relief valve
## Footnote
The pressure relief valve ensures proper lubrication system function.
43
What returns used oil back to the oil tank?
scavenger pumps
## Footnote
Scavenger pumps are crucial for maintaining oil levels.
44
Where are the sensors that measure oil temp and pressure?
between the oil filter and the engine
## Footnote
Sensor placement is key for accurate oil monitoring.
45
What do igniters do?
ignite air/fuel mixture during engine start
## Footnote
Igniters are essential for engine startup.
46
What are the ignition switches on during start?
STBY
## Footnote
This setting ensures ignition readiness during engine start.
47
When should the ignition switches be ON?
TO, approach, landing flight thru visible turbulence or precipitation low level operations
## Footnote
Active ignition during these phases is critical for safety.
48
Ignition in STBY arms the igniters when --
anti ice is engaged AOA detects approach to stall inflight engine restart
## Footnote
This feature is important for maintaining engine function.
49
What does the fuel control subsystem include?
HMU EFC
## Footnote
The fuel control subsystem is vital for managing fuel flow.
50
The HMU meters fuel based on ________.
throttle position
## Footnote
Throttle position is a key factor in fuel management.
51
How long is HMU solely responsible for fuel flow during engine start?
up to 38% N2 or when EFC OFF annunciator extinguishes
## Footnote
Understanding this timeframe is crucial for engine start procedures.
52
What does the EFC do?
refines the mixture of fuel flow and air
## Footnote
This refinement enhances engine efficiency.
53
What does the EFC use to refine fuel/air mixture?
engine speed, total air pressure, ambient conditions, throttle angle
## Footnote
These variables are critical for optimal engine performance.
54
What does the EFC do for the HMU?
allows for faster acceleration and generates the same percentage of max thrust for a given throttle angle
## Footnote
Faster acceleration is vital for performance.
55
EFC requires what type of power to operate?
DC
## Footnote
DC power is necessary for EFC functionality.
56
When does the safety shutoff valve turn off?
if it senses a failure of the turbine rotor shaft
## Footnote
This safety feature prevents further damage during a failure.
57
What is a turbine shaft failure indicated by?
loud bang and reading of zero RPM on N2
## Footnote
Recognizing these indicators is critical for safety.
58
When does the ENG FIRE PUSH switch light illuminate?
excess heat in the engine nacelle
## Footnote
Heat detection is vital for early fire warning.
59
What might an engine fire be indicated by?
high ITT, engine vibrations, sounds, trailing smoke
## Footnote
Recognizing these signs is essential for timely action.
60
What does the engine synchronization system do?
allows the crew to match engine RPMs to eliminate excess sound waves
## Footnote
Synchronization improves passenger comfort by reducing noise.
61
Which engine is the master in synchronization?
left
## Footnote
The left engine serves as the reference for synchronization.
62
Crew must match RPMs within _______ before the engine synch system takes control.
1.5%
## Footnote
This tolerance is crucial for maintaining engine balance.
63
If either engine EFC fails, what happens?
the synch system is inoperative
## Footnote
EFC failure affects engine synchronization capabilities.
64
What is bleed air used for?
heating, cooling, anti ice, pressurization
## Footnote
Bleed air plays a vital role in aircraft environmental control.
65
Does engine bleed air degrade performance?
yes
## Footnote
Understanding the implications of bleed air use is important for performance management.
66
What are vibration indicators used for?
helpful in spotting engine difficulties
## Footnote
Monitoring vibrations is key for early detection of engine issues.
67
Where are vibration indicators?
on each engine
## Footnote
Placement on each engine allows for localized monitoring.
68
Where does fuel start and end?
aft cabin, aft fuselage, main tanks, wing tanks, fuel feed chamber, engines
## Footnote
Understanding fuel flow is essential for managing fuel systems.
69
What does the fuel tank ventilation system handle and how?
pressure changes and surges, through allowing air to enter and exit the tanks
## Footnote
This system is crucial for maintaining fuel tank integrity.
70
What sends signals to the fuel fuselage quantity display on the MFD?
four fuel quantity probes
## Footnote
Accurate fuel measurement is vital for flight safety.
71
When are fuel quantity displays unreliable?
high AOA, angles of side slip
## Footnote
Understanding these conditions is important for accurate fuel management.
72
What is an electric pump?
utilizes electric power to turn and move fuel under pressure
## Footnote
Electric pumps are essential for fuel delivery.
73
What pumps do electric pumps operate?
transfer pumps and boost pumps
## Footnote
These pumps are critical for fuel system functionality.
74
What does the engine driven pump use for operation?
uses pressure from a mechanical pump driven by the engine accessory gearbox to provide pressurized fuel to the engine fuel control system
## Footnote
Understanding the engine-driven pump's operation is crucial for fuel management.
75
What must be operating for the engine driven pump?
the engine
## Footnote
The engine's operation is linked to the fuel delivery system.
76
What does the jet pump rely on?
motive flow with induced flow
## Footnote
Jet pumps are essential for transferring fuel efficiently.
77
What is the primary source of fuel for the engine driven fuel pump?
jet pumps
## Footnote
Jet pumps are crucial for maintaining engine fuel supply.
78
What feeds the fuel from the inboard bay into the feed chamber?
transfer jet pumps
## Footnote
Transfer jet pumps ensure proper fuel flow to the engines.
79
How does fuel transfer from aft cabin to aft fuselage to main tanks?
gravity
## Footnote
Gravity feed is a simple yet effective method of fuel transfer.
80
How do the mid tank get fuel to the wing tanks?
electric transfer pump
## Footnote
Electric transfer pumps are essential for moving fuel between tanks.
81
When do the transfer pumps stop sending fuel to wing tanks?
1. when pilot valve sends signal to shutoff valve 2. pressure switch in transfer line reads pressure is below 5 PSI +/- .5
## Footnote
These conditions ensure safe fuel management.
82
What is the normal position for the fuel trans switch?
AUTO
## Footnote
The AUTO setting optimizes fuel transfer operations.
83
How does the fuel move from wing tanks to engines?
gravity - outer to inner tanks. they feed fuel feed chamber
## Footnote
Gravity feed is a fundamental principle in fuel delivery.
84
What does the fuel feed chamber contain?
electric boost pump primary jet pump forward transfer jet pump aft transfer jet pump
## Footnote
The fuel feed chamber is critical for maintaining fuel pressure.
85
What do the forward and aft transfer jet pumps do in the fuel feed chamber?
move fuel from inboard bay inside
## Footnote
These pumps are vital for ensuring adequate fuel supply.
86
Where do the forward and aft transfer jet pumps get their power?
forward - motive flow from boost pump (only working if boost pump is active) aft - motive flow from boost pump or primary jet pump
## Footnote
Understanding power sources is essential for pump operation.
87
What does the primary jet pump do?
provides fuel under pressure from fuel feed chamber thru fuel feed line
## Footnote
The primary jet pump is crucial for maintaining engine fuel supply.
88
What does the primary jet pump require?
motive flow from engine driven fuel pump
## Footnote
The engine-driven fuel pump is essential for the primary jet pump's operation.
89
What does the primary jet pump setting do?
NORM - motive flow valve is open, allows jet pump to work OFF - closes valve; ceases operation
## Footnote
Understanding pump settings is critical for fuel system management.
90
What purpose does the electric boost pump serve?
fuel pressure during engine start (allows motive flow for primary jet pump) backup for primary jet pump origin of motive flow for aft and forward transfer jet pumps source of fuel pressure during xfeed
## Footnote
The electric boost pump is vital for ensuring fuel delivery during critical phases.
91
When does the boost pump turn on automatically?
engine start pressed fuel xfeed selected fuel feed chamber volume below full pressure in fuel feed line <5PSI
## Footnote
Automatic activation is crucial for maintaining fuel pressure.
92
What does the engine driven fuel pump supply and to what?
high pressure fuel to the engine fuel control system
## Footnote
High-pressure fuel is essential for proper engine operation.
93
When is xfeed used?
when one wing tank has more fuel than another
## Footnote
Crossfeed helps balance fuel loads between tanks.
94
Is pressure or gravity refueling better? Why?
pressure; faster, more gas
## Footnote
Pressure refueling is preferred for efficiency.
95
When does L or R XFR PRESS light up?
line pressure below 5 +/- .5 psi
## Footnote
Recognizing pressure issues is critical for fuel transfer.
96
Why would fuel transfer pumps in AUTO cause low pressure?
1. failure of transfer pumps (not moving from fuselage to wings) 2. failure of auto shutdown of transfer pumps (happens when fuel in mid tanks is near low AND pressure in fuel transfer line is below 5 +/- .5 psi)
## Footnote
Understanding potential failures is essential for troubleshooting.
97
What to do for low fuel transfer pressure checklist?
see if pump is operating. if it is and the tank is empty - pop circuit breaker to remove power from pump
## Footnote
Following checklists ensures safety during operations.
98
What to do for transfer pump if operation light is on, there is fuel in fuselage, and the XFER PRESS light is on?
remove power from pump, use xfeed as required
## Footnote
Proper troubleshooting is vital for fuel system issues.
99
What to do when -XFER PRESS - with fuel in fuselage, operation light is NOT on?
fuel transfer switch to ON - force pump to run. if annunciator continues; pull circuit breaker
## Footnote
Manually activating the pump can resolve transfer issues.
100
What does L or R WG TNK OV PRESS indicate?
pressure exceeds 3.5 +/- .5 psi in wing tank
## Footnote
Overpressure can lead to fuel system failures.
101
Why would WG TNK OV PRESS occur?
1. blockage in vent system 2. fuel transfer malfunction (if pilot or shutoff valve stops fuel from entering the wing via transfer pump; overfill = overpressure)
## Footnote
Identifying the cause is essential for resolving overpressure situations.
102
What to do in WG TNK OV PRESS?
level off. check to see if fuel transfer light is on - should be OFF when overpressure is sensed. light is off - RESET then AUTO for fuel transfer switch light is on - pull circuit breaker
## Footnote
Prompt action is necessary to prevent fuel system damage.
103
What does L or R FUEL LEVEL LO mean? What should you do?
wing has less than 200lbs / 32g of fuel left. verify, declare situation, land ASAP
## Footnote
Low fuel levels require immediate attention for safety.
104
What does L or R FUEL FEED mean?
fuel feed level low; fuel feed chamber has 70 lbs / 11g of fuel left
## Footnote
Monitoring fuel feed levels is critical for engine operation.
105
What to do in L or R FUEL FEED situation?
verify, place boost pump ON (takes fuel from inboard bay to feed chamber via forward/aft jet pumps & motive flow), if fuel LOW = land ASAP
## Footnote
Quick action is necessary to maintain engine fuel supply.
106
When does L or R F FLTR BYPASS annunciate?
when a 2.3 +/- .2 psi differential through the fuel filter is present. fuel is NOT being filtered
## Footnote
Filter bypass indicates a potential contamination risk.
107
What should you do when L or R F FLTER BYPASS lights?
land ASAP. if engine is erratic - consider shutting it down. if both lights light - suspect dual engine failure
## Footnote
Immediate landing is crucial to ensure safety.
108
What does L or R FUEL PRESS LO indicate?
pressure in fuel feed line drops below 5 +/- .5 psi
## Footnote
Low pressure can lead to engine fuel starvation.
109
What to do when L or R FUEL PRESS LO lights?
boost switch - ON jet pump - OFF (closes motive flow) these provide positive fuel pressure. if light continues complete engine shutdown during flight checklist
## Footnote
Following procedures is critical for safe operations.
110
Which sound annunciator cannot be silenced?
overspeed
## Footnote
The overspeed alert is critical for maintaining engine safety.
111
What detects the temperature of the gasses leaving the engine core? How many are there?
6 ITT thermocouples aft of high pressure turbine. compensated by 2 T1 probes
## Footnote
Accurate temperature monitoring is vital for engine health.
112
What does the low pressure turbine extract energy from?
exhaust gases from the engine core
## Footnote
This extraction is crucial for engine efficiency.
113
What does the fan and axial booster do?
draw air into the engine and split it into bypass (66%) and core flow (33%). most air bypasses core and provides thrust
## Footnote
Understanding airflow dynamics is key for engine performance.
114
What does bypass air aid in?
cooling the engine and quiets jet engine noise
## Footnote
Bypass air is essential for engine thermal management.
115
L and R FLTR BYPASS indicate _______ is being supplied to the engine.
unfiltered fuel
## Footnote
Unfiltered fuel can lead to engine damage.
116
L F FLTR BYPASS indicates a clogged ________.
left fuel filter
## Footnote
Monitoring filter status is crucial for engine health.
117
When the L F XFR PRESS LO annunciator lights before the fuselage tanks are empty, a possible malfunction to the left ______________ has failed.
transfer pump
## Footnote
Identifying pump failures is essential for troubleshooting fuel issues.
118
If a wing fuel tank overpressure occurs during a climb, you should ________.
maintain level flight
## Footnote
Level flight helps mitigate the risks associated with overpressure.
119
During flight with the R F FLTR BYPASS annunciator illuminated, consider shutting down the right engine if you observe ________.
rough engine operation
## Footnote
Engine performance monitoring is critical during flight.
120
With the amber L FUEL FEED annunciator lit, approximately _______ pounds (____ gallons) of usable fuel remains in the left fuel feed chamber.
70 pounds (11 gallons)
## Footnote
Low fuel feed levels require immediate attention.
121
The L WG TK OV PRESS lights if the left wing level control pilot valve malfunctions during ______________.
fuel transfer
## Footnote
Monitoring fuel transfer systems is crucial for operational safety.
122
Pressing the guarded LH ENG FIRE PUSH switch closes the ___________ and ___________________ system valves.
left fuel left hydraulic
## Footnote
This action is crucial for preventing further fuel and hydraulic flow.
123
A popped ___________ circuit breaker should not be reset.
fuel system
## Footnote
Resetting certain circuit breakers can lead to unsafe conditions.
124
The fuselage quantity gauge receives its input from probes in the ______________, ______________________, and _____________ tanks.
aft cabin, aft fuselage, and mid fuselage
## Footnote
Accurate fuel measurement is vital for flight safety.
125
The ____________ indicator displays the amount of fuel remaining in all fuselage tanks.
fuselage
## Footnote
Monitoring fuel levels in fuselage tanks is critical for operational safety.
126
Low fuel quantity is indicated by L or R FUEL LEVEL LO when approx ____ pounds or ____ gallons of usable fuel remain in the respective tank.
200 pounds / 32 gallons
## Footnote
Low fuel levels require immediate attention for safety.
127
guarded LH ENG FIRE PUSH switch closes the ___________ and ___________________ system valves
left fuel left hydraulic
## Footnote
This switch is critical for emergency procedures in case of engine fire.
128
a popped ___________ circuit breaker should not be reset
fuel system
## Footnote
Resetting a popped breaker can lead to further issues.
129
the fuselage quantity gauge receives its input from probes in the ______________, ______________________, and _____________ tanks
aft cabin, aft fuselage, and mid fuselage
## Footnote
These probes measure the fuel levels for accurate readings.
130
the ____________ indicator displays the amount of fuel remaining in all fuselage tanks
fuselage
## Footnote
This indicator is crucial for monitoring total fuel availability.
131
low fuel quantity is indicated by L or R FUEL LEVEL LO when approx ____ pounds or ____ gallons of usable fuel remain in the respective wing tanks
200 lbs 32 gallons
## Footnote
This alert helps prevent fuel exhaustion during flight.
132
during the fuel transfer process, gravity flow is used to move fuel from the ________ to the ____________ tank and then to the mid tanks
aft cabin, aft fuselage
## Footnote
Gravity flow is a simple and effective method for fuel transfer.
133
there are ________ fuel tanks located in the fuselage of the T1
4
## Footnote
Understanding the number of tanks is important for fuel management.
134
with the FUEL TRANS switch to the AUTO position, the transfer pump operates continuously until fuel in the mid tank is exhausted and the line pressure drops below __________
5 +/- .5 psi
## Footnote
This pressure threshold ensures efficient fuel transfer.
135
fuel to the ___________ comes directly from the fuel feed chamber
engine
## Footnote
Direct feed is essential for engine operation.
136
each wing tank contains ____________
3 bays
## Footnote
The configuration of bays affects fuel distribution.
137
during normal in-flight operations, the BOOST PUMP switch remains in _________
AUTO
## Footnote
This setting is optimal for fuel delivery under standard conditions.
138
if the BOOST PUMP switches are in AUTO, the appropriate boost pump automatically activates when the volume in the fuel feed chamber falls below approx ____ gallons
11
## Footnote
This automatic activation helps maintain fuel supply.
139
if the boost pump switches are in the ________ position, the electric boost pumps stop automatically following ___________
AUTO engine start
## Footnote
This feature prevents unnecessary energy use.
140
if the pressure in the left fuel feed line drops below 5 +/- .5 psi, the _______________ annunciator illuminates and the ____________ automatically starts
L FUEL PRESS LO boost pump
## Footnote
This alert is critical for maintaining fuel pressure.
141
the engine driven fuel pump supplies the motive flow to maintain primary ___________ operation
jet pump
## Footnote
The jet pump relies on motive flow for effective operation.
142
during normal operating conditions, positive fuel pressure is provided to the ______________ by the primary jet pump
engine driven fuel pump
## Footnote
This relationship is vital for engine performance.
143
during total electric failure, the __________ pumps are not affected (why?)
jet pump
## Footnote
Jet pump operation continues due to power from the engine driven fuel pump.
144
the motive flow line shutoff valve can be closed by placing the _____________ switches to _______
JET PUMP OFF
## Footnote
This action is necessary for maintenance or emergency procedures.
145
if icing inhibitor is not included in commercially purchased fuel, the fuel cannot be used unless the pilot ensures the proper amount of icing inhibitor is added _____________ refueling
BEFORE
## Footnote
Adding icing inhibitor is crucial for safe fuel use in cold conditions.
146
using fuel without icing inhibitor is __________________
prohibited
## Footnote
This prohibition is in place to ensure safety and prevent engine issues.
