DIRECT LAW

In most triple failure cases, direct law triggers.

When this occurs:

• Elevator deflection is proportional to stick deflection.
Maximum deflection depends on the configuration and on the CG

• Aileron and spoiler deflections are proportional
to stick deflection, but vary with the aircraft configuration

• Pitch trim is commanded manually

Handling characteristics are natural, of high-quality aircraft,
almost independent of the configuration and of the CG.
Therefore, the aircraft obviously has no protections,
no automatic pitch trim, but overspeed or stall warnings.

OPERATIONAL RECOMMENDATION:

The PF must avoid performing large thrust changes,
or sudden speedbrake movements, particularly if the center of gravity is aft.

If the speedbrakes are out, and the aircraft has been re-trimmed,
the PF must gently retract the speedbrakes,
to give time to retrim, and thereby avoid a
large, nose-down trim change.

INDICATIONS


The ECAM and PFD indicate any control law degradation.

ON THE ECAM

 In ALTN Law:

FLT CTL ALTN LAW (PROT LOST)
MAX SPEED 320 kt(320 kt/M 0.77 on A318)

 In Direct Law:
FLT CTL DIRECT LAW (PROT LOST)
MAX SPEED 320 kt/M 0.77

MAN PITCH TRIM USE ON THE PFD

The PFD enhances the PF’s awarness of the status of flight controls.

Specific symbols (= in green), and specific formatting
of low speed information on the speed scale
in normal law, indicate which protections are available.

When protections are lost, amber crosses (X) appear,
instead of the green protection symbols (=).

When automatic pitch trim is no longer available,
the PFD indicates this with an amber “USE MAN PITCH TRIM”
message below the FMA.

Fly-by-Wire Status Awareness via the PFD

Therefore, by simply looking at this main instrument (PFD),
the flight crew is immediately aware of
the status of flight controls, and the operational consequences.