B744 FLAPS

Question 1

How many Flap Control Units (FCU) are there and what are their purpose?

Answer 1

• 3
• Sequencing and monitoring of Flap operation
• Primary control, Secondary control indication & annunciation Ø
• TE Flap Asymmetry protection in Primary & Secondary modes
• Flap Load Relief on Primary mode only
• Flap position information to EICAS and other systems

Question 2

Where do I read the Flap display?

Answer 2

Primary EICAS

Question 3

How do the Flaps extend in Primary mode?

Answer 3

Hydraulically for TE Flaps & pneumatically for LE Flaps

Question 4

How do the Flaps extend in Secondary mode?

Answer 4

Electric motors for all TE & LE Flaps

Question 5

What EICAS message would indicate that the FCUs are inoperative, requiring the use of ALT Flaps?

Answer 5

FLAPS CONTROL

Question 6

What is the difference between the ALT Flap mode of extension and the Secondary Flap mode of extension?

Answer 6

While Elec motors are used in both modes, the sequencing is different:

• In the ALT mode, LE & TE extend together
• In the Secondary mode, Inbd & Midspan LE extend when the Flap lever is set at Flaps 1 and the Outbd LE extend when the Flap Lever is set at Flaps 5