Airbus Operation

Question 1

Why is it important reaching Cruise FL to ensure CRZ ALT mode is displayed on FMA

Answer 1

CRZ ALT on FMA means that in managed speed:

• Aircraft flies ECON SPEED as determined by the FMS
• ATHR operates in EPR soft mode

Question 2

What are the OPT, REC MAX and MAX MAX altitudes used by the FMS

Answer 2

• 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
- Higher than MAX REC, a message advises the crew that he is flying beyond the .3g boundary
• MAX MAX ALT: 0.2g buffer limit, managed modes are not available above that altitude

Question 3

Systems affected by a negative FMS NAV ACCURACY check

Answer 3

• AP&FD: managed or selected
• ND: Arc/Rose NAV or Rose VOR/ILS
• EGPWS: ON or OFF

Question 4

How is FMS position computed with GPS primary

Answer 4

• 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

Question 5

How is FMS position computed without GPS primary

Answer 5

• 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.

Question 6

Avoidance rule for a red echo on the weather radar

Answer 6

• 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

Question 7

Criteria used by the MCDU to compute the FUEL PRED page for a diversion

Answer 7

• 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)

Question 8

Maximum Rate of Climb Speed all engines operating and single engine (speed to reach a given altitude in the shortest time)

Answer 8

• All Engines operating, Turbulence Speed

* 1 engine inoperative, Green Dot

Question 9

Computation of characteristic speeds displayed on PFD and MCDU

Answer 9

• 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

Question 10

How do you quickly figure out the fuel needed in case of loss of 1 Engine

Answer 10

• 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

Question 11

Average Pitch / N1 for Take off, Cruise, Descent and Landing configurations

Answer 11

• Level off after Take Off

• Flaps 1 : 4° / 60%
• Flaps 2 : 8° / 62%
• Cruise : 2° / 75%
• Descent : 0° / Idle
• Approach Flaps 3: 3° / 50%

Question 12

Parameters for Long Range and Maximum Range

Answer 12

• Long Range (Specific range of 99% of Maximum Range): CI= 40
• Maximum Range: CI= 0, PERF section of FCOM in case of FMGEC failure