Getting to Grips with Approach-and-Landing Accidents Reducti(147)

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Wind shear;

Preventing Runway Excursions and Overruns
Page 1

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Cross-wind component;

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Inaccurate information on wind and/or runway conditions; and,

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Reverse-thrust effect in crosswind and on contaminated runway.

Crew technique or decision factors:
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Incorrect crosswind landing techniques (e.g., drifting during the decrab and align phase, absence of decrab when landing in high crosswind conditions);

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Inappropriate differential braking by crew;

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Use of nose-wheel-steering tiller at high speed; and,

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Vacating the runway at an excessive speed.

Systems factors:
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Asymmetric thrust (i.e., forward thrust on one side, reverse thrust on opposite side); or,

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Uncommanded differential braking.

Factors Involved in Runway Overruns
The following operational factors and circumstances are observed as recurring patterns, alone or in combination, in runway-overrun events:
Weather factors:
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Unanticipated runway condition (i.e., worse than anticipated);

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Inaccurate surface wind information; and,

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Unanticipated wind shear or tail wind component.

Performance factors:
.  Incorrect assessment of landing distance following an in-flight malfunction or an MEL condition affecting:
.  aircraft configuration (e.g., slats, flaps or roll spoilers);
.  lift dumping (e.g., ground spoilers);or,
.  braking capability (e.g., anti-skid);

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Incorrect assessment of landing distance for prevailing wind and runway conditions; and,

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Inoperative brake(s) not accounted for per MEL/DDG provision.

Crew technique or decision factors:
.  Unstable approach path (steep and fast):
.  Landing fast (up to V APP + 40 kt at runway threshold); and/or,
.  Excessive height over threshold (up to 220 ft) resulting in a long landing;
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Absence of go-around decision, when warranted;

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Captain (PNF)’s decision to land following intention or initiation of go-around by first officer (PF);

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Long flare ( allowing the aircraft to float to bleed an excess-speed uses three times more runway than decelerating on the ground );

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Failure to arm ground spoilers (usually associated with thrust reversers being inoperative);

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Power-on touchdown (i.e., preventing automatic extension of ground spoilers);

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Failure to detect the non-deployment of ground spoilers (e.g., absence of related standard call);

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Forward throttle/thrust levers movement resulting in the premature retraction of ground spoilers and in the loss of autobrake;

Preventing Runway Excursions and Overruns
Page 2

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Bouncing and incorrect bounce recovery; Standard operating procedures (SOPs):

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Late braking (or late takeover from autobrake system, when required); and,

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Reduced braking efficiency while assuring directional control in crosswind conditions.

Systems factors:
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Loss of pedal braking; or,

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Antiskid malfunction resulting in aquaplaning (as evidenced by extensive spots on all affected tires).

Prevention Strategies and Lines-of-Defense
The following prevention strategies and lines-of-defense should be implemented to address the factors involved in runway excursions and overruns:
Policies:
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Define policy and procedures to promote the readiness and commitment to go-around if the conditions for a safe landing are not achieved.
　
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