Safety First The Airbus Safety Magazine Edition February 2010(3)

qHow the new SEC standard will reduce the number of these occurrences.

4 Issue 9 | FEBRUARY 2010
qGround spoilers not armed (fig. 3)
..Both main landing gears seen
on ground.
..Reverse is selected on at least one
engine (the other thrust lever must be at or below Idle notch, fig. 4).

2.2 Partial extension
The Phased Lift Dumping function allows the ground spoilers to deploy with a reduced deflection and serves to accelerate the full spoiler exten-sion when landing in crosswind con-ditions or on contaminated runways.
The necessary conditions to trigger the partial ground spoiler exten-sion, independently of the position of the ground spoiler lever are: qOne main landing gear seen on ground. qReverse is selected on at least one engine (the other thrust lever must be at or below Idle notch).
3. In-service events
The genesis of this flight control computer modification is coming from two types of events:
3.1. Longitudinal runway excursion
Runway excursions resulted from the spoilers not extending during the landing.
This was traced to the following two causes:  qThe speed brake lever was in a non retracted position (fig. 5). qOne engine throttle was not in the area that authorized ground spoiler extension (fig. 6).

3.2. Hard landings
Among hard landings, one specific category has been identified where by the hard landing occurred after a bounce. They fit to the following scenario (fig. 7):
qeNo engine throttle reduc-tion (retard) during the flare pNo ground spoiler extension.
qrBounce induced by a too high energy level and by the lack of lift destruction.
qtEngine throttle reduction performed during the bounce p Ground spoiler extension if the retard is performed within 3 seconds following the first touchdown.
quSevere hard landing due to sudden loss of lift leading to a fall from a height of about 5ft to 15 ft.
It has been established that most of the hard landings occurring after a bounce are severe.
Safety

Figure 3

Figure 4

Full ground spoiler extention
Figure 5

Figure 6
The ground spoilers

The spoilers could not
were not armed

extend

The Airbus Safety Magazine Issue 9 | FEBRUARY 2010 5

Figure 8
Expanded ground spoiler arming condition based on more tolerant speed brake lever position.
Figure 9 Figure 10
Expanded ground spoiler extension condition based on more tolerant thrust lever position

4. Expandedground spoiler extension conditions
4.1. General philosophy
The Airbus philosophy regarding the ground spoiler activation logic is still based on the achievement of the following three conditions: qArming qGround detection qThrust lever position
The arming and thrust lever position conditions have been ex-panded to be more tolerant to in-appropriate speed brake and thrust lever positions.
　
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