A320: Flight Management
Terms in this set (72)
What is Flight Management?
2) Vertical and horizontal Flight planning management.
3) Performance prediction and optimization.
4) Navigation radio management.
5) Display management.
What are the navigation functions of FM?
-Evaluation of position accuracy
-Radio navigation tuning
-Alignment of IRS
What is "FM position"?
a position computed by each FMGC using either
MIX IRS+[(MIX IRS+GPIRS position)bias]
MIX IRS+[(MIX IRS+Radio Position)bias]
Pls refer FCOM if unclear. May need verification.
What is "Bias"?
The vector calculated from its MIX IRS position to its radio position or GPIRS position by each FMGC is called the bias.
What would happen if an FMGC were to lose its radio/GPIRS position?
The bias would be memorized and this would not change. The memorized bias is used to compute FM position until the radio postion or the GPIRS position is restored.
Can the flight crew manually update the FM position?
Yes. This also updates the bias.
When is the FM position update at takeoff inhibited?
When GPS primary is active.
What is a "Takeoff shift"?
a correction entered in the PERF page when the departure is from an intersection so as to provide the most accurate starting point for position calculations.
What is EPU?
Estimated Position Uncertainty. It is an estimate of how much the FM position diverged and is a function of the navigation mode in use. Highest UNCERTAINTY in IRS only. Lowest in IRS/GPS.
When is position accuracy considered HIGH?
When is position accuracy considered LOW?
What are the default area RNP values?
En route: 2 nm
Terminal 1 nm
~ GPS 0.3nm
~Other 0.5 nm
What is the priority logic for RNP?
Nav database procedure value
System default value
When a switch between NAV accuracy HIGH or LOW takes place, what is the indication you get?
MCDU and ND display NAV ACCUR UPGRAD (or DOWNGRAD) message.
In IRS/GPS mode, how many criteria do the GPS primary status combine?
1) Accuracy criterion (HIGH/LOW)
2) Integrity criterion (The capability to detect a failure and privide appropriate warning of it. This indicates the level of confidence the crew can have in the FMS position.
In terms of GPS accuracy, there are two criteria, namely-Accuracy criterion and Integrity criterion.
How would you know if both criteria have been met?
"GPS PRIMARY" is displayed on the MCDU and temporarily on the scratchpad.
In terms of GPS accuracy, there are two criteria, namely, Accuracy criterion and Integrity criterion.
How can you tell if one of these criteria are NOT met?
GPS PRIMARY LOST message appears on the MCDU and permanently on the ND. (The MCDU scratchpad memo can be cleared, but not the one on the ND)
What should the flight crew do if they lose GPS PRIMARY?
Periodically check position accuracy
-at 10 000 ft in descent.
When does the "GPS DESELECTED" message appear?
If GPS was deselected manually, "GPS DESELECTED" appears 80 nm before Top of descent or at the approach phase transition.
When does the ECAM display NAV/FM GPS POS DIAGREE message?
When GPS PRIMARY is active+FM position deviates from its respective GPS position by more than
-0.5' latitude below 55°
-0.9' latitude at or above 55°, but below 70°
What is predictive GPS?
GPS availabitlity prediction within ±15 min of ETA at a destination or a waypoint defined by the pilots.
When must the crew monitor navigation accuracy?
When entering a terminal/approach area
What are the ways in which the navigation radios can be tuned?
-Automatically via FMGS software.
-Manually via MCDU
-Manually via RMP (If both MCDUs or both FMGCs fail)
If one radio receiver fails, can the FMGC use the operative one to compute position?
When does the "SPECIFIC VOR-D UNAVAIL" message appear?
when the VOR/DME the flight crew requires for tuning is deselected,
When does the FMGC automatically tune an ILS?
1) Preflight or Takeoff phase- When the runway has an associated ILS
APPROACH or GO AROUND phase-
When the type of approach in flight plan is ILS
What are the protection in place in terms of ILS tuning?
-If the flight crew manually tunes an ILS that is different from that requested for automatic tuning, a "RWY/ILS MISMATCH" message appears.
-The FMGS logic prevents the flight crew from altering the course of an ILS when its frequency is identical to that selected in the flight plan.
What is the normal method of aligning the IRS?
by entering the company route or city pair and then pressing the ALIGN IRS line key of the MCDU.
How long does a normal alignment take?
How long does a rapid alignment take?
What is the purpose of a rapid alignment?
to refine the aircraft position when time is limited.
How can you tell that the alignment process has NOT been successful?
"IRS IN ALIGN" memo flashes in the E/WD
In what instances would the "IRS IN ALIGN" memo flash?
-when excessive motion has been detected. (Auto realignment starts)
-when a disagreement between the last memorized IRS position and the position sent by the MCDU occurs.
-mismatch in latitude computed and latitude sent by the MCDU
-IRS has not received a position altogether from the MCDU
What is overall navigation performance based on?
accuracy of the aircraft position computaion
validity of the flight path definition
what is an ARINC cycle?
the 28 day nav database update cycle
Can the aircraft takeoff with an outdated nav database?
Yes, but ONLY in exceptional cases after taking prior authorization from the national authorities and taking other precautionary measures.
What are the purposes of having an Active plan?
1) Lateral and Vertical guidance.
2) MCDU and ND display.
3) Radio navigation autotuning.
4) Performance predictions
5) Fuel planning
What are the purposes of having a Secondary flight plan?
1) to account for the probability of an alternate takeoff runway.
2) to plan a diversion
3) to prepare the next flight
4) to compare predictions or evaluations.
What are the main components of the ACTIVE flight plan or the SECONDARY flight plan?
1) Primary flight plan (from origin to destination and missed approach.
2) Alternate flight plan (From destination to alternate destination)
How can you enter a flight plan into the FMGC?
1) Automatically, by selecting a company route.
`i) Flight crew is aware of the presence of a company route-load that directly.
ii) Flight crew is unaware of the presence of a company route-enter the city pair and any and all company routes available will be automatically displayed in the route selection page.
2) By entering a city pair and then manually selecting the other information such as waypoints and other constraints.
What are the segments of a lateral flight plan?
Give examples for "Defined legs"
SID. STAR - TRANS
What is a "Discontinuity"?
When two waypoints have no leg defined between them.
What does the FMGS do with a "Discontinuity"?
It reverts to HDG(TRK) mode and flies direct between the two legs.
What type of legs can the flight crew create?
What is a DEPARTURE?
Departure=SID+En route transition
What is an ARRIVAL?
Arrival=APR VIA+STAR+En route transition
What are En Route Transitions?
in a SID:
the various possible trajectories between the last SID point and the first en route waypoint
and vice-versa for a STAR
What is an APPR VIA?
the various possible trajectories between the last point of a STAR and first point of an a APPR
What is a MANUAL LEG?
a pre-programmed leg in a SID or a STAR and these type of legs do not have termination points. the aircraft flies a constant TRK or HDG but NAV mode remains engaged on the assumption that the aircraft will proceed direct to the next way point when cleared.
Can a MANUAL LEG be user created?
No. Manual legs are parts of SIDS or STARS.
How many flight plans can the FMS hold?
How many legs can a flight plan hold?
200 Total=135 primary flight plan legs+65 alternate flight plan legs
What is the purpose of the temporary flight plan?
any changes that should be made to the active flight plan are made on the temporary flight plan and then entered in into the active flight plan.
Can waypoints be entered directly into the active flight plan without them being entered on a temporary flight plan first?
Where are predictions displayed?
ND and MCDU, each based on its own specific assumptions.
What is a Vertical deviation prediction?
in a descent, the system idicates the current vertical deviation from computed descent profile and predicts where the flight crew can rejoin it.
Where are short term predictions shown?
on the ND, based on the assumption that the aircraft will maitain its currently engaged modes.
Where are long term predictions shown?
on the MCDU, based on the assumption that managed guidance is active, or about to be re engaged.
What is REC MAX?
Recommended Maximum Altitude
is the lowest of the max altitude the aircraft
1) can reach with a 0.3g buffet margin.
2) can fly straight and level at MAX CRZ rating
3) can maintain V/S 300 f/m at MAX CLB thrust.
4) can fly at a speed higher than green dot and lower than VMO/MMO
5) the aircraft is certified at.
Where is REC MAX displayed?
on the PROG page
What is the "Energy circle"?
It represents the required distance to land from the aircraft's position down to the elevation airport at VAPP speed, considering all constraints on the vertical profile.
What causes the need for Performance and Idle factors?
To account for changes in
1) Actual aircraft drag
2) Actual engine performance
What is Performance Factor?
It corrects the predicted fuel flow model used for fuel prediction computations.
What is Idle Factor?
1) modifies the IDLE PATH (vertical descent profile)
2) makes a ∆ correction to nominal idle thrust.
When does the FMGS consider the aircraft to be in an "Engine out" condition?
-One engine master switch off
-N2 below idle
while the other is>22
-FADEC shows an engine fault
What speed does the aircraft maintain if an engine is lost in climb??
What would happen if terms of FM if an engine is lost in climb?
-Managed target speed changes to green dot.
-LVR MCT flashes white on the FMA
-Climb mode reverts to OP CLB and the aircraft slowly decelerates down to green dot speed.
-MCDU shows PERF CLB page with EO CLR promt
-PROG page shows the EO MAX REC ALT
What would happen in terms of FM if an engine is lost in cruise?
-Managed target speed is set to the higher of
~ Engine out cruise mach number/speed
-LVR MCT appears in white on the FMA
-PERF CRZ page appears with the EO CLR prompt
-PROG page displays EO MAX REC ALT
What would happen in terms of FM if an engine is lost in descent?
-Managed target speed remains unchanged. (ECON DES Mach number/speed, subject to any limitations)
-LVR MCT flashes in white on the FMA
-PERF DES page appears, showing EO CLR prompt.
-PROG page displays the EO MAX REC ALT
-The descent mode (if engaged) reverts to V/S, if the aircraft is above EO REC MAX. IF not, the descent mode is maintained.
What would happen in terms of FM if an engine is lost in he approach phase?
-Aircraft maintains VAPP
-LVR MCT flashes in white in the FMA
-PERF page appears with an EO CLR prompt
-progress page displays the EO MAX REC ALT
When is an EO SID displayed?
If an engine is lost in the Take off phase