Landing performance

[skwaL 36]

Hi,

While cruising I was playing around with landing performance in EFB, and when selecting NO CREDIT, ALL OP, Two INOP....calculated landing distance was all the same for me. Dont you need more runway if you have two inop reversers?

Also yesterday landing in Seattle it told me to use Autobrakes 4 so I dont run off the runway, I used autobrakes 4... and had almost half the runway remaining.

Any ideas?

[downscc 1,327]

I cannot answer to the first question regarding landing distance and equipment; however the second item is one that I played with extensively during beta testing and I think it has improved but there is still a limitation in the simulation platform that creates a problem.  Keep in mind that the landing distance required value is a very conservative number that includes flare distance within the touchdown zone and a 10% allowance.  The use of thrust reverse should only make a measurable difference at high speed but the reverse thrust effects in the simulator are too effective at low speeds.  I have found it useful to back off reverse thrust at 60 kt and use only autobraking at lower speeds.

[mfrantz 45]

Konstantin,

When you select autobrakes the selected reversers make no difference because the autobraking system is designed to maintain a specific constant deceleration rate for each AB setting. Therefore, if you have reversers on the autobrakes will adjust and apply less pressure to maintain the same deceleration rate as without reversers. You will only see a difference in landing distance with reverser settings if you select MAX MANUAL braking.

[skwaL 36]

41 minutes ago, mfrantz said:

Konstantin,

When you select autobrakes the selected reversers make no difference because the autobraking system is designed to maintain a specific constant deceleration rate for each AB setting. Therefore, if you have reversers on the autobrakes will adjust and apply less pressure to maintain the same deceleration rate as without reversers. You will only see a difference in landing distance with reverser settings if you select MAX MANUAL braking.

Thanks Michael that makes sense :)

[thibodba57 462]

1 hour ago, downscc said:

I cannot answer to the first question regarding landing distance and equipment; however the second item is one that I played with extensively during beta testing and I think it has improved but there is still a limitation in the simulation platform that creates a problem.  Keep in mind that the landing distance required value is a very conservative number that includes flare distance within the touchdown zone and a 10% allowance.  The use of thrust reverse should only make a measurable difference at high speed but the reverse thrust effects in the simulator are too effective at low speeds.  I have found it useful to back off reverse thrust at 60 kt and use only autobraking at lower speeds.

More accurate procedure would be to back off at 80 and idle reverse by 60.  You might get a couple hundred extra feet in that.  But that's how we are trained to use reverse (when we use it).  Otherwise if it's really not "needed" we are asked to do a Idle Reverse landing.