Airbus Operation Flashcards
Why is it important reaching Cruise FL to ensure CRZ ALT mode is displayed on FMA
CRZ ALT on FMA means that in managed speed:
- Aircraft flies ECON SPEED as determined by the FMS
- ATHR operates in EPR soft mode
What are the OPT, REC MAX and MAX MAX altitudes used by the FMS
• OPT ALT:
- Gives the best specific range (NM/kg) based on current gross weight, cost index, temperature and Wind
- Allow a minimum cruising time of 15 min
• MAX REC ALT:
- Provides a 0.3 g buffet margin at current gross weight and temperature assuming that anti-ice is off
- Allows a minimum rate of climb of 300 ft/mn at MAX CL thrust
- If one engine is out this field displays the recommended maximum engine-out altitude based on LRC speed assuming anti-ice is off
- If flying higher than MAX REC, the crew will be advised that he is flying beyond the .3g boundary by a message
• MAX MAX ALT: 0.2g buffer limit, managed modes are not available above that altitude
Systems affected by a negative FMS NAV ACCURACY check
- AP&FD: managed or selected
- ND: Arc/Rose NAV or Rose VOR/ILS
- EGPWS: ON or OFF
How is FMS position computed with GPS primary
- GPS interfaces directly with the IRS to output a GPIRS position
- When a GPIRS position is available it supersedes the RADIO position so that the FMS position tends to the GPIRS position
• GPS provides 2 essential data, additionally to position:
- ACCURACY of the Lat/Long position:
. Direct function of the satellite constellation in view of the aircraft. If the satellites are low on the horizon, or if their respective position is unfavorable, the resulting accuracy will be poor.
. It is provided as a “figure of merit”, this accuracy can be computed with a high probability of confidence
- INTEGRITY:
. Direct function of the number of satellites in view of the aircraft
. If 5 or more satellites are in view, several combinations of satellite signals may be used to process “several positions” and carry out tests on the satellite signals
• if GPS or GPIRS position fullfills the INTEGRITY and ACCURACY criteria, this position is the BEST RAW DATA position available
How is FMS position computed without GPS primary
• FMS position is derived from:
- 3 IRS positions blended into a MIX IRS position
- a RADIO position using 2 DMEs or a VOR/DME
- When a RADIO position is available, the FMS position tends towards the Radio position
- The FMS computes:
- The BIAS between MIX IRS and FMS position, to benefit from the latest update when the RADIO position becomes unavailable
- The ESTIMATED POSITION ERROR (EPE) of its own position.
Avoidance rule for a red echo on the weather radar
- Decide to avoid not later than 40NM from the Cell
- Avoiding distance:
- Upwind: 20 NM
- Vertically: 5000 ft above
- Aircraft below FL 230, OAT>0°:5NM / OAT <0°:10NM
Criteria used by the MCDU to compute the FUEL PRED page for a diversion
- Landing weight at destination
- Cruise level: FL 220 for less than 200NM, FL310 for more
- CI= 0, Maximum Range speed
- 0 wind (Alternate field of DES WIND page to insert a wind)
- Delta ISA at destination)
Maximum Rate of Climb Speed all engines operating and single engine (speed to reach a given altitude in the shortest time)
- All Engines operating, Turbulence Speed
* 1 engine inoperative, Green Dot
Computation of characteristic speeds displayed on PFD and MCDU
- Speeds displayed on PFD are computed by the FAC, FAC1 on PFD1 and FAC2 on PFD2
- Speeds displayed on MCDU, VLS, F, S and Green Dot are computed by the FMGC
• Computations made by FAC are based on:
- Below 14 500ft and 250kt:
Angle of Attack, Speed/Mach, Altitude, Thrust and CG
- Above 14 500ft or 250kt:
Gross weight information updated with a fuel consumption model within the FAC
How do you quickly figure out the fuel needed in case of loss of 1 Engine
- MCDU Fuel page is accurate for Single Engine Ops
- If MCDU Fuel page is not available, use this formula:
- Trip Fuel = 8 x Distance to destination
- Add 0.5 t for Approach
- Add 1.5 t for Reserve
• QRH In Flight Performance gives Fuel from any moment in cruise to Landing
Average Pitch / N1 for Take off, Cruise, Descent and Landing configurations
• Level off after Take Off
- Flaps 1 : 4° / 60%
- Flaps 2 : 8° / 62%
- Cruise : 2° / 75%
- Descent : 0° / Idle
- Approach Flaps 3: 3° / 50%
Parameters for Long Range and Maximum Range
- Long Range (Specific range of 99% of Maximum Range): CI= 40
- Maximum Range: CI= 0, PERF section of FCOM in case of FMGEC failure
