CE 680 FlightSafety PTM Sytem Questions Flashcards
1
Q
1 Aircraft General
The CE 680 is certified according to?
A
CFR Part 25
2
Q
1 Aircraft General
The micro switch that signals the amber [NOSE DOOR OPEN L-R] CAS message is located where?
A
At the mechanical latches
3
Q
1 Aircraft General
How can the emergency over-wing exit be opened?
A
Can be removed from inside or outside of the aircraft
4
Q
1 Aircraft General
Which publication must be immediately available to the Flight Crew?
A
The FAA approved AFM
5
Q
2 Electrical Power Systems
What can be expected if the RED [BATTERY O’TEMP] CAS message is displayed and the affected battery button is placed in the “OFF” position with the generators online?
A
Battery is isolated, but all Main DC powered items operate normally.
6
Q
2 Electrical Power Systems
If the AMBER [REMOTE CB TRIPPED] CAS message is displayed what has happened?
A
A circuit breaker has tripped that is not readily accessible by the Crew.
7
Q
2 Electrical Power Systems
What is permissible if a generator current is greater than the maximum flight limitation?
A
Is permissible provided the AMBER [DC GEN O’CURRENT] CAS message is not displayed.
8
Q
2 Electrical Power Systems
Primary DC Electrical Power sources include?
A
Engine Generators, APU Generator, GPU
9
Q
2 Electrical Power Systems
With regard to the batteries during engine starts, when are they included?
A
In every engine start ( except windmilling )
10
Q
2 Electrical Power Systems
How does the Electrical Bus Tie operation function?
A
Automatically on the ground and must be manually closed in flight.
11
Q
2 Electrical Power Systems
Which engine must be started first?
A
Either Engine may be started first.
12
Q
2 Electrical Power Systems
In the event of the RED [DC GEN OFF L-R-APU] CAS message is displayed:
A
(NJA) Consult the - DC Gen Off QRH
13
Q
2 Electrical Power Systems
The APU generator power is supplied to?
A
Left Emergency Bus only when the left Engine Gen is offline or unavailable.
14
Q
2 Electrical Power Systems
The AMBER [BUS TIE CLOSED] CAS message is displayed when?
A
In flight if the BUS TIE button is selected closed for more than 5 minutes with both Engine Gens online.
15
Q
2 Electrical Power Systems
If the Bus Tie is manually selected closed in flight, when does it automatically open?
A
When an overcurrent condition of over 600A is detected.
*Bus Tie will be latched open until aircraft is powered down.
16
Q
2 Electrical Power Systems
What triggers a RED [BATTERY O’TEMP L-R]?
A
When a battery temp exceeds 63° C.
17
Q
2 Electrical Power Systems
Considering electrical bus tie operation, primary sources of power consist of?
A
Engine Gens, APU Gen, GPU
18
Q
2 Electrical Power Systems
How and when does the Electrical Bus Tie open and close?
A
Automatically on the Ground and Manually in Flight. One exception in Flight is an over current of 600A + in which the bus tie will open Automatically and latch open.
19
Q
2 Electrical Power Systems
What kind of system is the Main Aircraft Electrical System?
A
A split bus system with two DC Generators and two DC Batteries.
20
Q
2 Electrical Power Systems
What does the WHITE AVAIL light signify on GPU Power Switch?
A
That the GPU is plugged in, running and the proper voltage is “Available” on the GPU Bus
21
Q
2 Electrical Power Systems
During a Ground Battery Start of the first Engine, what is the minimum Battery Voltage required?
A
Must indicate 24V or higher.
22
Q
2 Electrical Power Systems
What position should the generator switches be in for engine start?
A
On for all starts.
23
Q
2 Electrical Power Systems
What takes place when placing the INTERIOR Button to OFF on the electrical panel?
A
Remove all electrical power to the cabin except for Cabin Emergency lighting.
24
Q
2 Electrical Power Systems
If the left engine generator is powering the Left EMER bus what happens to the APU generator?
A
The APU generator will not come online.
25
2 Electrical Power Systems
How are the batteries used during engine start?
Both batteries assist in every engine start. Except windmilling starts.
26
3 Lighting
When are the Cabin Entry lights available?
With the batteries installed and connected the Cabin Entry lights illuminate if selected ON.
27
3 Lighting
What powers the Cabin Entry light button?
Cabin Entry lights are powered by the Right Battery Bus and on a timer.
28
3 Lighting
Selecting the PAX SAFETY button illuminates the….?
No Smoking Light and Cabin Emergency Lights.
29
3 Lighting
With the emergency light switch armed what turns on the emergency lights?
Cabin emergency lighting illuminates automatically upon loss of Main DC Power, a 5G impact, or with PAX SAFETY button selected on.
30
3 Lighting
With batteries installed and connected, but no power has been turned on in the cockpit, the following items are powered:
Book answer…Tail Cone Service lights, and Baggage Compartment lights.
Full answer.. Battery Hot Bus. PLANET CB
Pylon work light
Lav service door light
APU service panel
NWS bleed button light
ELT panel
Tail cone bay light
Cabin entry light
Baggage light
31
4 Master Warning System
Which Modular Avionics Units (MAUs) process aircraft Crew Alerting System (CAS) messages?
MAUs 1 and 4
32
4 Master Warning System
What is the purpose of the left and right monitor warning system (MW1 or MW2)?
To process and display CAS messages.
33
4 Master Warning System
How does the loss of a single Monitor Warning System affect the Master Warning System?
A loss of redundancy occurs for the monitor warning.
34
4 Master Warning System
What causes the large red “X” across the CAS display in the Engine Indicating and Crew Alerting System (EICAS) window?
The loss of MAUs 1 and 4.
35
4 Master Warning System
What is the default position of the EICAS window?
The default position is DU2.
36
4 Master Warning System
How is the EICAS system powered?
It is selected with its own switch separately from the avionics buttons.
37
4 Master Warning System
Can EICAS messages be displayed elsewhere?
EICAS window can be selected to the DU3 position with the EICAS reversion button after the AVIONICS buttons are selected on.
38
4 Master Warning System
How are RED CAS messages displayed?
Flash inverse video RED until acknowledged (reset) and illuminate the Flashing MASTER WARNING buttons.
39
4 Master Warning System
How are Amber CAS messages displayed?
Flash inverse video Amber until acknowledged (reset) and illuminate a steady Amber MASTER CAUTION light.
40
4 Master Warning System
How are CYAN CASS messages displayed?
Flash inverse video cyan and automatically self acknowledge after five seconds.
41
4 Master Warning System
How is invalid data displayed on the EICAS?
*Are displayed as Amber dashes in the place of numbers
*Does not activate any CAS messages
*Can be the result of a sensor failure
42
4 Master Warning System
Can EICAS messages be scrolled?
Only Amber and Cyan CAS messages can be scrolled up and down on the CAS display.
43
4 Master Warning System
How does the Engine Shut Down Inhibit (ESDI) function?
*ESDI is activated when the Engine Throttle is placed in Cut Off.
*The Amber [Engine Shut Down L – R] CAS message illuminates during ESDI.
*During engine start, ESDI is deactivated at start completion.
44
4 Master Warning System
What is the purpose of the standby annunciators?
The standby annunciators are a back up to selected EICAS instrument indications.
45
4 Master Warning System
Can you takeoff with a DU in reversionary mode?
No, dispatch with a DU and reversionary mode is prohibited.
46
4 Master Warning System
What is the limitation when a Comparison Monitor Warning is displayed ?
Autopilot operation is prohibited if any Comparison Monitor Warning is active.
47
5 Fuel System
How does a fault in the fuel quality system make itself known to the pilots?
By amber dashes displayed in the respective tanks EICAS fuel quantity digits display (invalid data).
48
5 Fuel System
The CE – 680 maximum fuel capacity is:
10,800 using single point fueling.
11,200 over the wing fueling.
49
5 Fuel System
When is it required for the single point refueling pre-check procedure to be completed?
Must be completed prior to every single point refueling operation.
50
5 Fuel System
How does a Main DC power failure affect the fuel Crossfeed Valve?
The Fuel Crossfeed Valve fails in its current position, parks.
51
5 Fuel System
The left fuel tank has 200 pounds more fuel than the right tank. What are the correct cockpit indications during crossfeed from left tank to right engine?
Cyan [FUEL BOOST L] and Cyan [FUEL CROSS-FEED] CAS message are displayed.
*Amber [FUEL CROSS-FEED] denotes fuel being cross fed from the incorrect tank (low tank, wrong way)
52
5 Fuel System
What can be done when one pre-check lever is pulled out on the single point refueling panel.
The selected fuel tank can be de-fueled, but not refuel.
53
5 Fuel System
If the left engine experiences low fuel pressure:
Amber [FUEL BOOST PUMP ON L] CAS message is displayed and the boost pump is auto on.
54
5 Fuel System
Fuel crossfeed from left tank to right engine may not occur if the:
Amber [FUEL MOTIVE FLOW VLV FAIL R] CAS message is displayed.
*Denotes associated Motive Flow Valve has failed to close and stop the engine feed jet pump.
55
5 Fuel System
With the fuel boost pump buttons in a NORM position, when will the boost pump run?
Fuel boost pump automatically activates for Engine Start, Fuel Crossfeed, and Low Fuel Pressure.
56
6 APU
What happens when the Red [APU FIRE} illuminates?
APU automatically shuts down and after eight seconds the BAG/APU fire bottle discharges.
57
6 APU
What does APU provide?
DC Electrical Power and Bleed Air?
58
6 APU
What happens when an APU fire detection system has failed?
Amber [APU FIRE DETECT FAIL] CAS message is displayed in the APU automatically shuts down.
59
6 APU
What happens if the shared BAG/APU fire bottle becomes low?
The APU shuts down.
60
7 Powerplant
The normal way to check the engine oil is?
Check for the Amber [OIL LEVEL LOW L-R] CAS message.
61
7 Powerplant
The PW 306 sea engines on the Sovereign are rated to?
Rated at 5770 pounds thrust at sea level up to 30° C.
62
7 Powerplant
The Amber [GROUND IDLE] CAS message illuminates when?
When the FADEC remains in ground idle mode while the aircraft is airborne.
63
7 Powerplant
The N1 target indicator (bugs) turn amber when?
When the monitoring FADEC channel is unable to set the N1 bug and it is subsequently posted by the controlling FADEC channel.
64
7 Powerplant
How is Engine Sync indicated when it is active?
It is displayed as a green SYNC annunciation above the EICAS N1 tapes when the engines are synchronized.
65
7 Powerplant
What makes up the FADEC system?
The FADEC consist of two EEC’s (A and B channel) and an Engine Diagnostic Unit (EDU).
66
7 Powerplant
What happens with the ignition switch is in a NORM position.
With the ignition switch in the norm position, Ignition is applied as required by the FADEC.
67
7 Powerplant
What does pressing the event marker button accomplish?
Records 5 minutes of the Engine Parameters in the EDU for later inspection. Four minutes prior to the button one minute after.
68
8 Fire Protection
What happens when the Smoke Detector detects smoke in the baggage compartment?
The BAG FIRE light illuminates and the Baggage Heat Shutoff Valve automatically closes.
69
8 Fire Protection
What areas are monitored by the Fire Detection System?
Engines (Fire), APU (Fire), Baggage Compartment (Smoke).
70
8 Fire Protection
During flight with respect to the fuel system, what occurs when the LH ENG FIRE PUSH button is pressed?
The Cyan [FUEL F/W SHUTOFF] CAS message illuminates after the valve closes.
71
8 Fire Protection
What happens if the Red BAG FIRE button is pushed?
Immediate Discharge of the BAG/APU fire bottle located in the Tail Cone (HDR) and a Metered Discharge of the Baggage Fire Bottle (MDR) located in nose compartment into the baggage compartment.
*The APU also shuts down if running due to loss of Fire Portection.
72
9 Pneumatics
What does the Pressure Source Selector on the Bleed Air panel control?
Bleed Air from the Engines for Environmental and Pressurization applications only.
73
9 Pneumatics
What does the NORM selection on the L/R Bleed Air Selectors do?
Selects LP or HP pressure according to Normal Logic.
74
9 Pneumatics
What happens when the Bleed Air Leak Detection Systems detects and over temperature situation?
Specific Bleed Air Valve close to isolate the Zone where the condition was detected.
75
9 Pneumatics
What does the Left Bleed Air Selector control?
It controls engine bleed air entering the Left Pylon Pre-cooler.
76
9 Pneumatics
When is Baggage Heat available?
It is available airborne only with the left engine bleed operating.
77
9 Pneumatics
With the Baggage Heat button in the NORM position and after landing the aircraft, what happens to the baggage heat valve?
It Closes
78
9 Pneumatics
What happens with an ACM BLEED LEAK.
Emergency Pressurization Bleed Air activates automatically.
79
10 Ice and Rain Protection
What powers the windshield heat.
Two Engine Driven Alternators.
80
10 Ice and Rain Protection
The Electrically Powered Anti-Ice systems on the Sovereign include?
RAT Heat, Windshields, Pitot/Static Heat, AOA Heat.
81
10 Ice and Rain Protection
Which Anti Ice Systems use Bleed Air?
Engine Spinner (Always heated), Engine Inlet and Stators, Wing Leading Edges, Horizontal Stab Leading Edges.
82
10 Ice and Rain Protection
What happens with a Main DC power failure with respect to the Pneumatic Anti Ice System
Bleed Air for Anti-Icing is still on but bleed air temperature monitoring is off.
83
10 Ice and Rain Protection
The Amber [WING ANTI-ICE O’TEMP L] CAS message means?
Left wing anti-ice is too hot and the shut off valve has closed.
84
10 Ice and Rain Protection
The Cyan [ENG ANTI-ICE COLD] CAS message indicates?
That after the anti-ice system Is selected on it is inhibited for two. Five minutes on the ground and 2.5 minutes in flight.
85
10 Ice and Rain Protection
How are the RAT anti-ice heaters powered?
They are electrically heated when the ENG/STAB anti-ice buttons are on.
86
10 Ice and Rain Protection
Windshield rain removal is provided by?
W/S fan on the ground or in-flight and a rain repellent coating during flight.
87
10 Ice and Rain Protection
The amber [RAT HEAT FAIL] CAS message indicates?
The ENGINE/STAB ant-ice buttons are ON and the engines RAT probes are not receiving electrical current.
88
10 Ice and Rain Protection
The windshield anti-system contains the following components:
AC alternators, DC controllers, heating elements in the front and side windows, and temperature sensors.
89
10 Ice and Rain Protection
The Cyan [INBD WING A/I COLD L-R] CAS message on the ground indicates that?
ENGINE/STAB anti-ice was selected ON and the Wing LE Surface has not reached it’s minimum operating temperature.
90
10 Ice and Rain Protection
Ice detection is provided by?
Two Red ice detention lights pointed at the underside of the windshield and two wing inspection lights.
91
10 Ice and Rain Protection
What happens when ant-ice over temperatures are detected?
Anti-ice over temperature sensors automatically shut off bleed air to the affected area.
92
10 Ice and Rain Protection
What happens when selecting the WING/STAB XFLOW button to XFLOW?
The CYAN [WING A/I CROSSFLOW OPEN] CAS message is displayed when the valve opens.
93
10 Ice and Rain Protection
What is heated when the ENG/STAB ANTI-ICE is selected ON?
Bleed Air is supplied to the Nacelle, Stator Vanes and INBD Wing Leading Edge, and Electrical Heat is sent to the RAT probes.
The Nose Cone is heated anytime the engine is operating and so is the Engine Spinner.
94
5 Fuel
What is the meaning of the Reverse Highlighted Amber Fuel Indication?
If an individual tank quantity display is less than 500 pounds, or if total fuel quantity display is less than 1000 pounds, then the respective quantity indication will turn from Green to Amber inverse video.
95
5 Fuel
What does an Amber [FUEL LEVEL LOW L-R] indicate?
Fuel in the respective hopper has dropped below 540 lbs +/- 60.
Fuel Boost Pump on the affected side will be turned on per the QRH.
96
11 Air Conditioning
The temperature control valves TCV’s control Cockpit/Cabin temperature by?
Mixing cold ACM air with pre-cooled bleed air bypassing the ACM for the under floor ducting.
97
11 Air Conditioning
Air entering the cabin through the overhead WEMAC system is?
Recirculated cabin air mixed with cold air from the ACM.
98
11 Air Conditioning
How can you monitor the air entering the cockpit or cabin through the underfloor duct?
Temperatures can be monitored with the SUPPLY position on the temperature controller.
99
12 Pressurization
The amber fault light illuminator on the pressure controller indicates?
The controller has failed and automatically switch to manual mode.
100
12 Pressurization
When does the Cyan [CABIN ALTITUDE] CAS message illuminate?
The cabin altitude cast message illuminates when the cabin altitude has exceeded 8000 feet and the Pressurization controller is set for the high altitude airfield mode.
101
12 Pressurization
How is the cabin altitude limited to its maximum altitude?
Maximum Cabin altitude is limited to approximately 14,500 feet by cabin altitude limiters.
102
12 Pressurization
What happens if the Pressurization controller fails or if there is a loss of Main DC power?
Cabin pressure must be controlled with the Red CABIN ALT manual toggle lever.
103
13 Hydraulic Power System
The hydraulic systems main components include?
A reservoir and fluid, two engine driven pumps, an auxiliary pump, and pressure/volume indicators.
104
13 Hydraulic Power System
What systems are hydraulically powered?
Speedbrakes/Roll Spoilers, Landing Gear, Brakes/Anti-skid, and Nose Wheel Steering.
105
13 Hydraulic Power System
While airborne, what signals the loss of both hydraulic pumps?
An AMBER [HYDRAULIC PRESSURE LOW L-R] CAS message
106
13 Hydraulic Power System
In an emergency standby hydraulic pressure may be obtained by?
There is no standby hydraulic pressure available in flight.
107
13 Hydraulic Power System
What does the Main Hydraulic System Reservoir preflight require?
Reference to a temperature/pressure placard on the ground service panel to determine the correct reservoir pre-charge pressure.
108
14 Landing Gear and Brakes
What does the Amber [ANTISKID FAIL] CAS message indicate?
It illuminates if an anti-skid fault is detected or if the switch is turned off.
109
14 Landing Gear and Brakes
The proper method of checking brake wear during pre-flight is to set the parking brake and ensure that?
The brake wear indicator pen is not recessed into the caliber housing.
110
14 Landing Gear and Brakes
If the Amber [ANTISKID FAIL] CAS Message illuminates prior to landing and the message cannot be extinguish what do you have available?
Power breaking is still available, but antiskid protection is lost and landing distance must be extended.
111
14 Landing Gear and Brakes
What is required for nose wheel steering to be operable.
You need hydraulic system pressure and main DC power for nose wheel steering to operate.
112
14 Landing Gear and Brakes
How is nose wheel steering deactivated when there is an uncommitted nose wheel deflection?
An uncommitted nose wheel to flexion can be overcome by pressing, and holding, the red AP/TR I M/NWS button on either yoke.
113
15 Flight Controls
How are the primary flight controls operated
All primary flight controls are manually operated no hydraulic system pressure required.
114
15 Flight Controls
Roll controls consist of what components?
Ailerons and hydraulically actuated Roll Spoilers.
115
15 Flight Controls
What happens when a jammed roll control occurs and the PITCH/ROLL DISCONNECT handle is pulled?
The primary flight controls are broken out and the Pilot’s control column is connected to the Ailerons and Left Elevator, and the Co-Pilot’s control column is connected to the spoilers and Right Elevator.
116
15 Flight Controls
What flight controls does the PITCH/ROLL DISCONNECT affect?
It breaks out the ailerons and spoilers and the left and right elevator.
117
15 Flight Controls
What is the minimum altitude for the speedbrakes to be deployed?
Speedbrakes should be stowed below 500’ AGL.
118
15 Flight Controls
What does the primary pitch trim system control?
The electrically controlled movable horizontal stabilizer.
119
15 Flight Controls
Can the flap handle be set in between flap positions?
No the flap handle may only be set in the slotted positions 0° 7° 15° and 35°. If the handle is set anywhere in between a [FLAP FAIL] CAS message will occur and the flap reset button will illuminate.
120
15 Flight Controls
What does the flap stabilizer interconnect system do?
It automatically trims the horizontal stabilizer when the flaps are in motion between 15 and 35 with or without the auto pilot engaged.
121
15 Flight Controls
What does the MACH trim system do?
It trims a stabilizer/elevator flow tabs above 0.77 Mach.
122
15 Flight Controls
How does the Rudder Bias system function?
It requires bleed air pressure from the engines.  It is rigged so that the loss of air pressure from one of the engines will cause the actuator to kick the rudder in the proper direction for single engine operation.
123
15 Flight Controls
How does speed affect the Rudder Bias operation?
The amount of travel is less above 125 KIAS if an engine fails.
124
15 Flight Controls
When the Rudder Gust Lock is engaged how is takeoff prevented?
The Cyan [GUST LOCK] CAS message is illuminated and contributes to the [NO TAKEOFF] warning system.
125
15 Flight Controls
How is the crew alerted to a fault in aileron ratio changer
The Amber [ROLL SYSTEM CONTROL FAULT] CASS message is displayed on the EICAS.
126
15 Flight Controls
What controls the primary flight controls?
Primary flight controls are manually controlled with the yoke via pulleys and cables.
127
15 Flight Controls
What will happen if you try to take off with either the ROLL/PITCH DISCONNECT and/or the Stabilizer trim not in a takeoff position?
It would trigger the [NO TAKEOFF] warning system on the EICAS.
128
16 Avionics
What happens when the standby power switch is selected on?
The lead acid battery and the nurse compartment powers of standby instruments for 180 minutes during emergency bus operation.
129
16 Avionics
When will the Auto Pilot EMERGENCY DESCENT mode activate?
When the auto pilot is engaged, the airplane is above FL310 and the cabin altitude exceeds 14,500 feet.
130
16 Avionics
How is the TOLD/V speed information originating from the FMS displayed?
FMS derived data is displayed in magenta digits.
131
16 Avionics
What temperature indications are displayed in the Primus EPIC system?
SAT, ISA, and RAT are displayed on the MFD. RAT is also displayed on the EICAS.
132
16 Avionics
The changer-over (C/O) button on the flight guidence control panel does what?
It allows the crew to change the digital speed indication on the PFD between IAS and Mach speed.
133
16 Avionics
During cruise flight, altitude hold is verified when?
The green ALT annunciation is displayed in the top of each PFD scorecard.
134
16 Avionics
When the left HSI is an arc mode how can you change the range?
The left CCD can select range on the left HSI and the right CCD changes the range on the right HSI
135
16 Avionics
The standby flight display SFD displays navigation information from what source?
From NAV1 or FMS1 through the menu button only if the standby HSI fails.
*This answer doesn’t make sense! Need to verify*
136
16 Avionics
When are the AOA indication shown on the left PFD?
Continuous or automatic operation is selected through the left MCDU.
137
17 Oxygen System
How many oxygen bottles are on the Sovereign?
One oxygen storage bottle in the fuselage fairing. There is an option for a second long range bottle.
138
17 Oxygen System
What is the acceptable pressure for an oxygen during pre-flight?
Pressure within the green arc on the oxygen pressure gauge indicates an acceptable preflight pressure range.
139
17 Oxygen System
What does selection of the PASS OXY knob to AUTO do?
It arms a mask for automatic deployment at 14,500 feet of cabin altitude.
140
17 Oxygen System
What does selecting the PASS OXY knob to OFF do?
Shut off O2 pressure to the passenger oxygen mask only crew masks still have oxygen available.
141
17 Oxygen System
How are the crew oxygen mask tested during pre-flight?
They are preflight tested while remaining stowed in their service box.
142
17 Oxygen System
How are the passenger oxygen mask operated after being deployed?
A lanyard/cord that attaches the mask to it’s respective dropbox must be pulled in order to receive oxygen through the mask.
143
17 Oxygen System
Either the normal or extended range oxygen system quantity can be pre-flight from where?
Requires oxygen quantity preflight from the cockpit only.
144
17 Oxygen System
When do the red indicator lights on the extended range control panel Illuminate?
They illuminate only if the pressure in the supply line from the respective bottle is low.
145
17 Oxygen System
During the emergency bus condition, how does the PASS OXY knob function?
It deploy’s the passenger masks when in the ON position. Auto function requires Main DC
146
17 Oxygen System
Memory items associate with SMOKE/FIRE/FUME (NJA)
Oxygen mass and goggles Don in emergency, establish crew communications, and then call for the Smoke/Fire/Fume QRC.
*This is NJA specific.
147
17 Oxygen System
What is the highest cabin altitude for crew and passenger oxygen masks?
Crew and passenger oxygen mask or not approved for use about 40,000 feet cabin altitude.
148
17 Oxygen System
What qualifies the crew masks as quick dawning masks?
The crew masks must be properly stowed in their containers to qualify as quick donning oxygen masks.
149
17 Oxygen System
With respect to the oxygen system if the aircraft has been exposed to prolong temperatures below -9° C what must be accomplished?
The cabin must first be warmed up to at least 60° F on the cabin temperature gauge if the aircraft is to be flown above FL250.
