Rwy

[Vicar]

I was reading about the use of reverse thrust when i came upon this :

Idle reverse on long dry runway
Full reverse on wet runway
Full reverse on contaminated runway

I asked someone to define contaminated runway which was wet runway. In this case, if a contaminated was a wet runway, then why don't they just state "Full reverse on wet runway" or "Fullreverse on contaminated runway" alone? Why do they have to state both? Is contaminated runway more then just a wet runway?

Btw, in calm conditions or least wind not exceeding 30knots, roughly what would the be the speed of the aircraft on touchdown?

Thanks in advance

Vicar

 

[avbug]

Vicar,

A difference exists between a wet runway, and a contaminated runway.

A wet runway is one that is neither dry nor contaminated.

By definition, a contaminated runway is a runway where more than 25 percent of the required field length, within the width being used, is covered by standing water or slush more than 0.125 inch (3.2 mm) deep, or that has an accumulation of snow or ice. However, in certain other situations it may be appropriate to consider the runway contaminated. For example, if the section of the runway surface that is covered with standing water or slush is located where rotation and liftoff will occur, or during the high speed part of the takeoff roll,, the retardation effect will be far more significant than if it were encountered early in the takeoff while at low speed. In this situation, the runway might better be considered contaminated rather than "wet."