Flight Controls -Flaps & Slats DSC 27-30 Flashcards
Each wing has how many flaps?
2
Each wing has how many slats?
5
How are the flaps and slats controlled and operated?
Electrically controlled
Hydraulically operated
What are the main components of the slat/flap system?
- 2 Slat Flap Control Computers (SFCC’s)
- A power control unit
- 5 slat & 2 flap surfaces per wing
- An Asymmetry position pick-off unit
- A Flap disconnect detection system
- Wing Tip Brakes
- Feedback position pick-off units
- Instrumentation position pick-off unit
How many channels do the SFCC’s have?
One slat channel and
One flap channel
What does the power control unit consist of?
2 independent hydraulic motors coupled by a differential gearbox
Which hydraulic systems power the slats?
Green and Blue
Which hydraulic systems power the flaps?
Green and Yellow
What component locks the transmission when the slat or flap surfaces have reached the selected position, or if hydraulic power fails?
Pressure-off brakes (POBs)
What does the asymmetry position pick-off (APPU) measure?
The slat or flap asymmetry between the left and right wings
What does the flap disconnect detection system detect?
Attachment failure and inhibits flap operation in order to prevent further damage
How does the Flap Disconnect Detection system sensor detect a failure?
By measuring excessive differential movement between inner and outer flaps
When are Wing Tip Brakes (WTB) activated?
Asymmetry
Mechanism overspeed
Symmetrical runaway
Uncommanded movement of the surfaces
Can WTB be released in flight?
No
Which hydraulic systems do the WTB use?
Green and Blue -Slats and Right Wing Flaps
Green and Yellow -Left wing FLaps
If the slat WTB’s are on, can the pilot still operate the flaps?
Yes
And if the slat WTB’s are on the flaps are still operable
At what speed do the slats and flaps operate if one SFCC is inoperative?
Half speed
At what speed do the slats and flaps operate if one hydraulic system is inoperative?
Half speed
corresponding surfaces, slats or flaps
If a take-off is carried out at heavy weight, what two protections may intervene?
- Automatic Retraction System (ARS)
- Alpha Lock function
When will the Automatic Retraction System activate?
When in CONF 1+F and IAS reaches 210kts
VFE CONF 1+F = 215 kts
What happens when Automatic Retraction system activates?
While in CONF 1+F and IAS reaches 210kts (VFE-5kts)
Flaps automatically retract to 0.
VFE now CONF 1 (230 kts)
What is the purpose of the Alpha/Speed Lock function?
Inhibits slat retraction at:
High angles of attack, and
Low speeds
At the moment the flap lever is moved from Flaps 1 to flaps 0
What information do the SFCC’s use to inhibit slat retraction as part of the Alpha/Speed Lock function?
Corrected AoA or airspeed information from the ADRIU’s
When the FLAPS lever is set to 0, the slats allpha/speed lock function will activate and inhibit slat retraction if:
- The AoA is above 8.5°, or
2. The speed is less than 148 kts
How do you know the Alpha Lock function has activated?
‘A-LOCK’ pulses green (cyan-YUD) above the E/WD slat indication
When is the Alpha Lock inhibition removed and the slats retract to 0?
When both Alpha and Speed fall within normal values:
AoA less than 7.6°, and
Speed above 154 kts
Is Alpha Lock function activation a normal situation for a heavy weight take-off?
Yes
What should the crew do if Alpha Lock function is activated?
Continue the normal acceleration, allowing further slats retraction
The VMAX on the PFD is based on…..?
The Slat/Flap Control lever position
The OVERSPEED WARNING is based on….?
The actual Slat/Flaps surface position
What does amber FLAP, slat/flap position, S and F indications indicate?
Both relevant hydraulic systems fail
WTB are on
Slats or flaps fault
