Flight Management/Navagation Flashcards
Components of the Navigation System
- 2 GPS receivers (GPS L and GPS R)
- Inertial Reference System (IRS)
- 3 Inertial Reference Units (IRUs)
- IRS Mode Selector Panel
- 2 ADFs (L and R)
- 2 DMEs - 5Chs each (L and R)
- 3 ILSs (L, C, R)
- 2 VORs (L and R)
- 2 Transponders (L and R)
- 2 WX Radar units (L and R)
- Flight Management System (FMS)
- 2 Flight Management Computers
- 3 Control Display Units (CDUs)
Inertial Reference System
- gyros and accelerometers (acceleration sensors) are used to calculate:
- airplane position
- acceleration
- track
- vertical speed
- ground speed
- heading (T and M)
- attitude
- 3 Inertial Reference Units (IRUs) translate date to other aircraft systems
Normal and Fast Alignment times
Normal Alignment - 10 mins
*must be completed when arrival time since previous full alignment exceeds 18 hrs
Fast Alignment - 30 sec
When is ILS Approach tuning inhibited?
- AP on and LOC or GS captured
- Below 500 RA; FD engaged and LOC or GS captured
- On the Ground; LOC alive; within 45º of course; great than 40 knts GS
Data required in the FMS Preflight phase
- initial position
- routed of flight
- performance data
- takeoff data
How does FMC update/calculate position
On the Ground:
- IRS and/or GPS data
- with GPS inactive, TO/GA buttons update to runway threshold/position shift position
* with GPS active TO/GA update is inhibited
In Flight:
- IRS position updated by GPS/Nav Radio data (compensates for inertial ref errors)
ILS/LOC approach
- LOC signal updates FMC position
Priority source for FMC position data
1) GPS
2) Nav radio source
3) IRS(at lease 1 IRU required)
Standard Radio Navigation Performance (RNP) levels
RNP 0.15 - RNAV/RNP Approach RNP 0.3 - RNAV/GPS; RNAV/GNSS Approach RNP 1.0 - Terminal area RNP 2.0 - Enroute operation RNP 10 - Oceanic
What speed is commanded in VNAV at acceleration height?
At Accel height:
- flap speed -5 knts
After flap retraction:
- V2+100, or
- speed transition associated with departure airport
Databases contained in FMC
- navigation (2 sets, updated every 28 days)
- operation program configuration (OPC) -airplane manufacturer configurable data
- aero engine database (AEDB) - engine performance data
- MAGVAR tables
- airline modifiable information (AMI)
Reference Thrust setting options
- TO
- TO-1
- TO-2
- D-TO
- D-TO-1
- D-TO-2
- CLB
- CLB-1
- CLB-2
- CRZ
- CON
- GA
Reduced Thrust Takeoff options
Derated/Variable
- TO-1, TO-2
- thrust setting parameter is considered a limitation for Takeoff
- thrust levers should not be moved further forward except in an emergency
Assumed Temperature
- reduces takeoff thrust depending on assumed temperature entered
- max thrust reduction is 25%
- thrust setting is not considered a limitation
Derated Thrust Climb
CLB 1:
- 10% of climb thrust to 10,000’
- thrust increases to CLB thrust at 15,000’
CLB 2:
- 20% of climb thrust to 10,000’
- thrust increases to CLB thrust at 15,000’
When is FUEL USED value reset
- at each engine start
- after a long power interruption on the ground
What are fuel predictions based on
- the active route
- flaps, landing gear up during climb, cruise, and descent
What is unusable during DUAL FMC Failure?
- VNAV
- LNAV
- Autothrottle
IRS POS entry options during initialization
- LAST POS
- REF AIRPORT
- GATE
- GPS POS
- manual Lat/Long
When do LNAV/VNAV activate after being armed prior to takeoff?
- LNAV at 50’
- VNAV at 400’
What is Econ Cruise Speed based on?
Cost Index
What does DES NOW prompt command?
- descent guidance at approx 1250 fpm until established on planned descent path
- descent rate can be adjusted by manually repositioning thrust levers
How is information displayed with dual FMC failures?
- Alternate Navigation
- CDUs use internal computing and respective IRUs for performance calculations
- CDUs continuously memorize and copy FMC flight plan
- CDU L: provides info to CA
- CDU R: provides info to FO
- CDU C: backup based on selector
How are Radios tuned in Alternate Nav mode?
- CDU L tunes left radios
- CDU R tunes right radios
- CDU C tunes center ILS
*Autotune is not avail
What does VNAV command after takeoff?
V2 +10 to V2 + 25
How is speed controlled in VNAV SPD and VNAV PTH
VNAV SPD - speed controlled by pitch
VNAV PTH - speed controlled by thrust
What is VNAV PTH during descent based on?
- idle thrusts
- Speedbrakes retracted
- FMC Cruise wind
- wind entries
- planned use of anti-ice
- target speeds
How is a fast alignment accomplished?
- Airplane must be parked
- Position the selectors to ALIGN
- Enter present position
- Reposition the selectors to NAV
- Takes 30 seconds
What happens when IRS alignment is lost in flight?
• The navigation mode is inoperative for the remainder of the flight
• Attitude information can be obtained by moving the selector to ATT
*Heading info is available by inputting heading in FMC
What happens to the center IRU when operating on DC power?
Center IRU operates for 5 mins and then shuts down
How are navigation calculations performed during Alternate navigation
- each CDU uses its internal memory and inputs from respective IRU
- CDU’s do not have performance or nav database
- CDU continuously copies the active route from the FMC during normal operations
Waypoint operations during Alternate Nav
- new waypoint (lat/long only)
- remove existing waypoints
- change sequence of existing waypoints
- connect discontinuities
Alternate Navigation CDU pages
- Alternate Navigation Legs (IRS LEGS)
- Alternate Navigation Progress (IRS PROGRESS)
- Alternate Navigation Radio
What is the meaning of PARK displayed in the ILS frequency
No frequency is tuned
Arrows next to traffic targets when TCAS is displayed
Traffic climbing or descending at 500 fpm or greater
Red or Amber TRAFFIC displayed on ND
- RA (red) or TA (amber) is occurring
- displayed in all ND modes
- regardless if TCAS traffic is displayed or not
IRS position updating priority
- LOC and GPS
- LOC and DME/DME
- LOC and collocated VOR/DME
- LOC
- GPS
- DME/DME
- collocated VOR/DME
What is calculated by the Inertial Reference System (IRS)
- airplane position
- acceleration
- track
- vertical speed
- ground speed
- true and magnetic heading
- wind speed and direction,
- attitude data
What happens if you move an IRS selector out of NAV?
Alignment is lost
What is accomplished with a realignment of the IRS?
- accumulated track, ground speed, and attitude errors are removed
- relevels the system
- updates present position
Where does HDG information on the PFD and ND come from?
- operating IRU in NAV mode
- independent of IRS source selector if operating FMC is selected
What is provided in IRS ATT mode?
- Attitude
- Heading
