Aircraft Systems Flashcards
Two flying references may be used on the PFD:
‐ The attitude
‐ The Flight Path Vector (FPV), called the “bird”.
The attitude flight reference should be used for dynamic manoeuvres, for
take-off or go-around.
The bird is computed from
IRS data and is affected by inertial errors. During the approach, the flight crew may detect a small track error, usually up to +/-2 °.
The bird is also computed from static pressure information. Therefore, if the altitude information is not reliable, the flight crew must consider the bird as not reliable.
When using the “bird”, the flight crew should first change attitude, and then
check the result with reference to the “bird”.
The FPV is particularly useful for ___ type of approach.
APPROACH USING FPA GUIDANCE
flight crew can select values for the inbound track and final descent path angle on the FCU.
The TRK-FPA Flight Director (FD) is particularly useful for
guiding the aircraft during non-precision approaches, although, it can also be used at other times.
If the FCU is set on the correct track and flight path angle, and if the FPV and the FPD are aligned, they will
guide the aircraft along a trajectory that is stabilized with respect to the ground, whereas when the pilot is using HDG-V/S, the trajectory is stabilized with respect to the air.
If the aircraft is disturbed from this ideal trajectory, merely following the FPD will result in its following a trajectory that is parallel to the intended trajectory. Thus, when the aircraft is disturbed from the original trajectory, the pilot must
adjust either its track or its flight path angle or both in order to obtain guidance back to the original trajectory.
The flight crew should position the tail of the “bird” on the blue track index on the PFD , in order to
maintain the desired track downwind.
On the final inbound approach, the track index should be set to the final approach course of the runway. A standard 3 ° approach path is indicated, when
the top of the bird’s tail is immediately below the horizon, and the bottom of the “bird” is immediately above the 5 ° nose down marker.
FINAL APPROACH
The “bird” is a very useful flight reference, because it provides
the trajectory parameters, and quickly warns the pilot of downburst.
The position of the “bird” in relation to the fixed aircraft symbol provides an immediate indication of the wind direction. Therefore, when approaching the minimum, the flight crew knows
in which direction to search for the runway.
If the target approach speed symbol moves upward, this indicates that there is headwind gust. If the “bird” drifts to the right, this indicates that there is wind from the left.
For the go-around, the appropriate flight reference is the attitude, because
go-around is a dynamic maneuver. When performing a go-around, regardless of the previously-selected flight reference, upon selection of TOGA, the FD bars are automatically restored in SRS/GA TRACK modes, and the “bird” is automatically removed.
There is inevitably some lag between the pilot’s raising the nose to commence the go-around and the aircraft’s responding by changing its trajectory.
RECOMMENDED PRACTICE FOR AUTOPILOT (AP) ENGAGEMENT
Before engaging the AP, the flight crew should:
‐ Fly the aircraft on the intended path
‐ Check on the FMA that the Flight Director (FD) is engaged with the appropriate guidance modes
for the intended flight path. If not, set the FD on, and the appropriate guidance mode(s) as
required
‐ Center the FD bars with the aircraft symbol on the PFD.
Engaging the AP while large orders are required to achieve the intended flight path may result in
an AP overshoot of the intended vertical or lateral target. This situation can surprise the flight crew, due to the resulting large pitch/roll changes and thrust variations.
If not using FD orders, turn off the FD. It is strongly recommended to turn off the FDs to ensure
the A/THR is in SPEED mode if the A/THR is active.
The A/THR can only be active, when the thrust levers are between
IDLE and the CLB detent.
When the thrust levers are beyond the CLB detent, thrust is controlled manually to the thrust lever Angle, and the A/THR is armed (A/THR appears in blue on the FMA). This means that
the A/THR is ready to be re-activated, when the flight crew sets the thrust levers back to the CLB detent (or below).
___ will, therefore, be the maximum normal thrust setting that will be commanded by the A/THR in CLB, CRZ, DES, or APPR, as required.
MAX CLB
If the flight crew is going to make the landing using manual thrust, the flight crew should disconnect the A/THR by the time the flight crew has reached
1 000 ft on the final approach.
If the flight crew makes a shallow flare, with A/THR engaged, it will increase thrust to maintain the
approach speed until the flight crew pulls the thrust levers back to idle.
In a one-engine inoperative situation, A/THR can only be active, when thrust levers are set between
IDLE and MCT.
In case of engine failure, the thrust levers will be in MCT detent for remainder of the flight.
INSTINCTIVE DISCONNECT (I/D) PUSHBUTTON
If the I/D pb is pressed when the thrust levers are in CL detent, thrust will increase to
MAX CL. This will cause an unwanted thrust increase and may destabilize the approach.
The recommended technique for setting A/THR to off is:
‐ Return the thrust levers to approximately the current thrust setting, by observing the TLA symbol
on the thrust gauge
‐ Press the I/D pb.
Thrust levers are set to IDLE, A/THR is set to
OFF
As a reminder, the “RETARD” aural alert will sound. In flare, this aural alert will occur at ___, except in the case of autoland, where it occurs at ___.
20 ft / 10 ft
The A/THR can be reactivated by pressing the pushbutton on the FCU, and returning the thrust levers to the applicable detent. The thrust levers should be immediately returned to the applicable detent, in order to avoid an ECAM
“AUTO FLT A/THR LIMITED”
When pressed, thrust is ___ when the flight crew pressed the A/THR pb, as long as the thrust levers remain in the CLB or MCT detent.
frozen and remains locked at the value it had
An ECAM caution and an FMA message trigger during thrust lock:
‐ THR LK appears on the FMA
‐ The AUTO FLT A/THR OFF ECAM alert is triggered
‐ The ENG THRUST LOCKED ECAM alert is triggered, if the thrust levers are not moved within 5 s.
In this case, when the flight crew moves the thrust levers out of detent, full manual control is recovered, and the THR LK message disappears from the FMA.
When the aircraft’s angle-of-attack goes beyond the ALPHA FLOOR threshold, this means that the
aircraft has decelerated significantly (below ALPHA PROT speed): A/THR activates automatically and orders TOGA thrust, regardless of the thrust lever position.
ALPHA floor is available, when the flight controls are in NORMAL LAW, from
liftoff to 100 ft RA at landing. It is inhibited in some cases of engine failure.
NAVIGATION ACCURACY CROSSCHECK TECHNIQUE
The principle consists in comparing
the FMS position with the RADIO position
On the ND, the flight crew compares the position of the needle and its associated DME distance (the real position of the aircraft) with the position of the NAVAID symbol and its associated distance, indicated by the range markers (these markers provide a bearing/distance, in relation to the FMS position).
POSITION UPDATE
In case of an obvious and major map shift noticed by specific messages such as
“CHECK A/C POSITION, FM1/FM2 POS MISMATCH”
POSITION UPDATE
Two techniques are
The recommended technique is to carry out a FMS update over a beacon by pressing the UPDATE prompt once estimating that the aircraft overflies the beacon using the associated needle. The potential error induced is approximately 4 to 5 NM. When the position update is achieved, the EPE is automatically set to a higher value and the navigation accuracy is low.
The second technique consists in updating the FM position when flying over a Point/Bearing/Distance (P/B/D) with reference to beacon raw data (Needle + Distance) rather than the beacon itself. The potential for error is far less when the distance is greater than 60 NM. The flight crew will keep in mind the potential 180 ° error on bearing.
The aircraft Gross Weight (GW) and Centre of Gravity (CG) are computed independently by the
FM and FAC
GW and CG values FM computed are used for:
- FM predictions and speeds
- ECAM(GW)
- MCDU(GWandCG)
- Computation of characteristic speeds (VLS, F, S, GD) for display on PFD
GW and CG values FAC computed are used for:
- Flight control laws
The FMGC computes the GW and CG from:
‐ The ZFW, ZFWCG inserted in the INIT B page
‐ The fuel quantities from the FQI
‐ The Fuel Flow from the FADEC
GW and/or CG is used:
‐ For FM predictions and speeds ‐ For ECAM display (GW only)
‐ For MCDU (GW and CG)
‐ By FAC for characteristic speed computation for PFD.
The FAC computes its own GW and CG from
aerodynamic data
