FLAP SYSTEM Flashcards
How many Flap Control Units (FCUs) are provided?
• Three
FCOM, VOL 2; 9.20.13
What are the basic functions of the FCUs?
- Primary control
- Secondary control
- Indication and annunciationFCOM, VOL 2; 9.20.13
How many groups of leading flaps are provided, and how are they normally powered?
- Three groups on each wing: outboard, midspan, and inboard section.
- Normally pneumatically powered from the bleed air duct of your respective side.FCOM, VOL 2; 9.20.13
What are the two groups of trailing edge flaps, and how are they powered?
• Inboard and outboard
• Inboard powered by hydraulic system 1 and outboard by
system 4
FCOM, VOL 2; 9.20.13
How are opposite trailing edge flaps connected?
• Mechanically, in order to maintain symmetry.
FCOM, VOL 2; 9.20.13
What protection features do FCUs provide for trailing edge flaps in primary mode?
- Asymmetry protection,
- Disagree and uncommanded motion,
- Flap load relief for flaps 25 and 30, and
- Flap position information to EICAS and other systemsFCOM, VOL 2; 9.20.13
What protection features do the FCUs provide for trailing edge flaps in secondary mode?
- Asymmetry protection,
- Disagree and uncommanded motion,
- Flap position information to EICAS and other systems.FCOM, VOL 2; 9.20.13
Describe the function of the FCUs in primary mode?
- LEF are driven pneumatically to the selected position.
- TEF are driven hydraulically to the selected position.FCOM, VOL 2; 9.20.13
Describe the function of the FCUs in secondary mode?
• If any flap group fails to move to the commanded position, the
FCUs switch to secondary mode for the related group.
• The flap group is driven through electric motors.
- the change is for symmetrical flap groups on both wings.
FCOM, VOL 2; 9.20.14
What happens if a primary control failure occurs in either the inboard or midspan leading edge flap group?
• Both groups switch to secondary mode.
FCOM, VOL 2; 9.20.14
What happens if a failure occurs in a leading edge flap group on one Wing?
• The flap groups on both wings change to secondary mode after a time delay.
• The non-affected side completes movement before changing to secondary
mode, due to the rapid rate of primary mode flap movement.
FCOM, VOL 2; 9.20.14
What happens immediately if a trailing edge asymmetry is detected?
• Primary mode is immediately shut down for the
asymmetric group.
• The FCUs do not use secondary mode
• FLAP CONTROL EICAS Caution Message If all three FCU’s fail.
FCOM, VOL 2; 9.20.13
What EICAS Advisory message displays if all three FCUs fail in their control function?
• FLAPS CONTROL EICAS Caution message.
FCOM, VOL 2; 9.20.13/ 9.30.1
How does the Flap Alternate Control mode work?
• Bypasses the FCU’s, so no protection is provided.
• Is manually selected
• All flaps are extended or retracted by electric motors.
• Flap selector is inoperative.
• After arming the alternate mode, extension and retraction is
accomplished with the Alternate flaps selector.
FCOM, VOL 2; 9.20.14
Is there any asymmetry protection in alternate flap mode?
• No
FCOM, VOL 2; 9.20.14
State the actions that occur when the Alternate (ALTN) Flaps Arm switch is pushed?
- Arms flap alternate control mode
- Arms alternate flaps selector
- Shuts off primary and secondary mode operation,
- Asymmetry protection is not available.
- Flap lever inoperative.FCOM, VOL 2; 9.10.8
What is the maximum extension of the trailing edge flaps in alternate mode?
• 25
FCOM, VOL 2; 9.10.8
Describe the secondary mode or non-normal expanded flap position indication for leading edge flaps?
- All flap positions are displayed
- White box outline shows LEF group retracted
- White crosshatch shows LEF group in transit
- Solid green box shows LEF group extended
- Amber boarder - Drive unit inoperative with flap group retracted.
- Amber solid box – Drive unit inoperative with flap group extended.
- Amber cross hatch- Drive unit inoperative with flap group partially extended.FCOM, VOL 2; 9.10.11
Describe the secondary mode or non-normal expanded flap position Indication for trailing edge flaps?
- White – position of inboard and outboard TEF
- Amber – asymmetry or drive failure in related groupFCOM, VOL 2; 9.10.11
What does an amber “X” mean on an expanded flap display?
• Position sensor for respective flap has failed.
FCOM, VOL 2; 9.10.11
Describe the Alternate Mode Expanded Flap Position Indicator?
- All flap positions displayed
- Flap position index marks at 5 and 25
- Indicator motion is continuous between flap detents.FCOM, VOL 2; 9.10.12
Describe the flap position indication on EICAS if the standby bus is the only powered AC bus?
• The left wing TEF sensors are not powered.
• An amber X is displayed on the left outboard and inboard TEF
indications.
• An expanded indication is displayed.
FCOM VOL 2 9.20.15
What flaps extend when the flap lever is moved from UP to Flaps 1?
• Inboard and midspan leading edge flap groups.
FCOM, VOL 2; 9.20.14
What flaps extend when the flap lever is moved from Flaps 1 to Flaps 5?
- Trailing edge flaps move to Flaps 5 position.
- Outboard leading edge flap groups extend.
FCOM, VOL 2; 9.20.15
What flap sequencing occurs when using alternate flaps?
• During extension, all LEF and TEF groups extend immediately.
• TEF extend to a maximum of 25.
• During retraction, all LEF groups retract after inboard TEF are
completely retracted.
FCOM, VOL 2; 9.20.15
Describe flap load relief?
• Protect s the flaps from excessive air loads if airspeed limits are
exceeded with flaps 25 or 30 selected.
• If airspeed limit is exceeded , the flaps will retract to 25 or 20 to eliminate
the exceedance.
• Flaps extend once airspeed is sufficiently reduced.
- Flap load relief is not available in secondary or alternate mode.
FCOM, VOL 2; 9.20.13
How long does the flap indication on primary EICAS remain displayed after all flaps are up?
• 10 seconds
FCOM, VOL 2; 9.20.15
What is the affect on the flap system during engine reverse thrust operation?
• Inboard and midspan leading edge flaps retract automatically
- Flap position indicator changes to reflect flaps in transit.
FCOM, VOL 2; 9.20.15
