FCOM

Question 1

What’s in FCOM PRO Special operations?

Answer 1

Flight without pressurisation 
Flight with gear down
Flight over mountainous area
Engine intermix ops
RVSM
RNP perf 
Narrow runways
QNH >1050

Question 2

What is Alpha lock?

Answer 2

Inhibits slat retraction at high angles of attack and low speeds.
SFCC’s use corrected AoA or airspeed info from ADIRU’s.
If alpha exceeds 8.5 degrees or or airspeed drops below 148kts retraction from 1 to 0 inhibited.
Inhibition removed when AoA goes below 7.6 degrees and the speed exceeds 154 kts.

FCOM Flight Controls

Question 3

Describe how the windshear warning systems work and what is required for them to work?

Answer 3

Predictive windshear:
The system scans the airspace, within a range of 5 NM ahead of the aircraft, for windshears. Below 1 500 ft, when the system detects windshear, depending on the range selected on the ND, a warning, caution, or advisory message appears on the ND. Predictive windshear warnings and cautions are associated with an aural warning.
Predictive windshear warnings and cautions are associated to an aural alert and to a red (warning) or amber (caution) “W/S AHEAD” message on the PFD, whereas windshear advisories are only displayed on the ND (Refer to DSC-34-SURV-30-30 PWS (if installed) indication on PFD and ND ) without message on the PFD.

During final approach, the visual and aural warning alerts are downgraded to caution alerts between 370 ft AGL and 50 ft AGL, and range between 1.5 NM and 0.5 NM. If a caution alert occurs during approach, consider use of CONF 3 and increasing VAPP to a maximum of VLS+15.

At takeoff, alerts are inhibited above 100 kt and up to 50 ft.
During landing, alerts are inhibited below 50 ft.
The aural alerts of the Predictive WindShear system (PWS):
Have priority over TCAS, GPWS, and other FWC aural warnings
Are inhibited by reactive windshear detection and aural messages of stall warnings.

Reactive windshear:
The windshear detection function is provided by the Flight Augmentation Computer (FAC) in takeoff and approach phase in the following conditions:
At takeoff, 3 s after liftoff, up to 1 300 ft RA
At landing, from 1 300 ft RA to 50 ft RA
With at least CONF 1 selected.
The warning consists of:
A visual “WINDSHEAR” red message displayed on both PFDs for a minimum of 15 s.
An aural synthetic voice announcing “WINDSHEAR ” three times.
WINDSHEAR DETECTION PRINCIPLES

The FACs generate the windshear warning whenever the predicted energy level for the aircraft falls below a predetermined threshold.
In computing this energy level prediction, the FACs use data from different sources. From ADIRS comes data such as vertical speed, air and ground speeds and slope ; from other sources come such derived parameters as total slope, longitudinal wind gradient, and vertical wind.