737 Perf. inflight Actual LDG distance
 

Hi all, a quick question regarding the 737 Performance inflight Actual LDG distance table:

The table lists corrections for 'No reverser' and '1 reverser'.
Now I understand why this is the case with MAX MANUAL braking, but why does it list corrections for different autobrake settings as the autobrakes provide a decelleration RATE. ie they apply less brake pressure when you use reverse thrust.

Thanks

For the same reason as in an Airbus. The reversers help in the deceleration once the aircraft starts braking: they help in achieving the selected deceleration-rate by the autobrake. Once the selected deceleration-rate is attained the reversers have no further effect on deceleration.
In other words: it takes time for the autobrakes to deliver the required brakepressure and achieve the decel rate, up to the point where the selected deceleration is attained the reversers have a cumulative effect.

Thanks OPEN DES for your reply. Still, why is the correction higher with a lower autobrake setting. You would expect the deceleration rate to be achieved sooner with a lower a/b setting, and thus a smaller correction to the landing distance.

Thanks IGh. Very interesting reading.

Hello I-d-s.

I am no expert whatsoever...

But it would help if you could show us the data itself and the corrections to be applied. Are they expressed as a % of the distance or as an absolute corrections in meters?

Cheers