Ah good one simon great job. But you wouldn't be able to dispatch surely because your LDA is more than 60%

???

 

Actual landing distance = 1207m

 

Landing distance available = 2011m

 

1207/2011 x 100 = 60% (actually 60.01%, but bear in mind we are rounding the nearest metre, which TOPCAT probably isn't internally).

But the actual landing distance is the unfactored distance without the 1.67 safety margin for dry runways;

 

Dispatch requirement is 1.67

But the actual landing distance is the unfactored distance without the 1.67 safety margin for dry runways;

 

Dispatch requirement is 1.67

For dispatch you use Landing Distance Required. LDR already includes the necessary factors. If there is sufficient runway available, as there is in Simon's example, you can go.

As Kevin says, can we stop within 60% of the available runway?

 

60% of 2011m = 1207m (rounded).

 

Actual landing distance = 1207m (rounded).

 

Therefore, yes.

 

The 1.67 factor is what we multiply the actual landing distance by to find the minimum runway length required, including the safety margin.

Ok guys my head has been in the books too long! So you always want LDA equal to or greater than LDR.

 

so actual landing distance is the absolute distance without any factor been added ie 1.67 or 1.92 for wet?

 

My understanding is that for PLANNING ie pre-dispatch you must ensure your LDR is not more than 60% of the LDA - I don't think that sounds right?

I'll try again:
 

The actual landing distance is the distance required to stop the aircraft from 50ft over the threshold, using maximum braking, FCOM technique etc etc. This does not include any additional safety factors.

 

In order to dispatch, the law requires that we can stop the aircraft in no more than 60% of the declared landing distance available. To calculate whether we can land, we multiply the actual landing distance by 1.67 (this is actually an approximation, but close enough) to give us the minimum landing distance we require for dispatch.

 

As long as this figure is equal to or less than the LDA we are good -- it includes the safety margin. You don't add safety margins on to safety margins otherwise you'd never be able to get in anywhere!

I understand thanks. And of course the WET factor is 1.15 or 15 % but thats already in the B/A < GOOD in the QRH PI

Does TOPCAT use reverse thrust in the calculation for In-flight?

 

Also for In-flight if you use autobrake 1-3 the LDR always equals ALD, But when you choose autobrake MAX and MAX manual the ALD drops below LDR why is this?

 

 

Does TOPCAT use reverse thrust in the calculation for In-flight?

 

Doesn't matter if you're using autobrake. I'm guessing that may be why the MANUAL brake setting is offered.

I know for the QRH PI credits the use of reverse thrust (well in my JAA QRH does) not sure about other sources, because at the end of the adjustment table you have the option to choose one reverse inop or both.

Hmm somehow the calculation for WET / CONT is off!? Because i've multiplied the ALD by 1.92 and its not matching the LDR.

 

landing Distance actual = 1653

Landing distance required = 1715

This is the wrong forum to be discussing Aerosoft's TOPCAT accuracy/features... take it to Aerosoft forum for their support.

This is the wrong forum to be discussing Aerosoft's TOPCAT accuracy/features... take it to Aerosoft forum for their support.

It turned out it wasn't a problem with TOPCAT, more an operational issue.

It turned out it wasn't a problem with TOPCAT, more an operational

 

Maybe so, but the WET runway factors is wrong. Pretty sure of that!!

Maybe so, but the WET runway factors is wrong. Pretty sure of that!!

That definitely isn't solvable in this forum. Use DRY and apply your own factors.