Non-Normal Configuration Landing Distance Dry Runway

[Driver 170]

In my QRH

737-800W/CFM56-7B26 Performance Inflight - QRH
JAA
Category C/N Brakes
Advisory Information
737 Flight Crew Operations Manual


at the bottom where the text is, it mentions;

Actual (unfactored) distances are shown.

What is this applying? Does this mean the 1.67 rule needs to be added to the reference distance?

Also this confuses me, its from a line student training document; The dry figures in the QRH are the actual landing distance i.e. unfactored while GOOD, MEDIUM etc. are factored by 1.15 (15%)

The Dry runway landing distances in the QRH are the actual landing performance distances, i.e. unfactored. The Dry runway figures are the absolute landing distance and therefore require careful evaluation to ensure that aircraft configuration and landing conditions are relevant to the landing runway.

What is unfactored?

[Driver 170]

Just to add to my last paragraph isn't it a requirement to add this rule -

CAT.POL.A.230 Landing — dry runways

(a) The landing mass of the aeroplane ... shall allow a full stop landing from 50 ft above the threshold:
(1) for turbo-jet powered aeroplanes, within 60 % of the landing distance available (LDA);

So why has it mentioned QRH landing distance, unfactored?

[Mad (Flt) Scientist]

because the rule about only using 60% of the LDA is in the context of a planned, normal, landing. You're mixing the normal and non-normal circumstances.

In the event of a failure, you do not need a 60% margin, and it would be actually unsafe to require one, as in some cases the extra distance induced by the failure, multiplied by the normal 1.67 factor, would greatly limit the choice of landing sites.

So instead a crew are told the true distance for a failure, and expected to apply airmanship in judging how much margin over the absolute minimum they should have, given the failure and any other circumstances. Obviously it is prudent to have some margin.

[Driver 170]

Ok thanks alot for clearing that up. I suppose each operator in the ops manual a will specify a safety margin? Or leave it solely to the commander to exercise sound judgment of airmanship.

So why are the QRH normal landing distances unfactored for dry runways and for GOOD, MEDIUM etc. are factored by 1.15 (15%)

Also for PRE-DISPATCH, will you require LDR or...

Landing Field Limit Weight - Dry Runway
Flaps 40
Based on anti-skid operative and automatic speedbrakes

[Pin Head]

Adding to this does anyone have a performance guide book for NG?

Please PM if you want.

[Driver 170]

I got the ATPL studies from oxford aviation and also download the 737NG PRH EASA

PERFORMANCE REFERENCE HANDBOOK 737 (http://www.performance737.com)