Slasher and Mutt,
The 737 QRH I was using last year had unfactored landing data and I presumed that Slasher was referring to a difference between that earlier data and something which has come out in recent months ? Mutt appears to be contrasting factored and unfactored ? ... or am I just confused ... ? If, in fact, the change relates to a change in philosophy post accident, then I guess I may have been using the same document (or similar) to which Slasher refers.
I would still urge considerable caution in the use of QRH unfactored data. This will have been generated for the nominated conditions using the aircraft performance model and will be untested. I would be surprised if it contains any fat at all.
What I have used as a teaching philosophy in this area (assuming that the operational situation presents a little bit of time) is something along the lines of the pilot doing some initial sums on the basis of 1.43 (cf alternate landing in some jurisdictions - rounded off to 1.5 for convenience) and 1.67 (cf normal - rounded off to 1.7). As part of his/her risk assessment a runway under consideration can be categorised as "normal" (>1.67), requiring considerable care (1.67 - 1.43), requiring extreme care and precision in the landing (1.43 - 1.00), and guaranteeing an overrun (<1.00). If the runway is wet, then the 1.15 type of factor can be included to suit. (I suggest that the idea of undershooting to pick up some extra ground distance is fraught with danger).
If there is only one feasible alternative for recovering the aircraft, then the above reduces to an assessment of the degree of care required for the landing and emergency facilities pre-arrival briefing.
If there are no options at all and no time .. then give it your best shot and hope that Lady Luck is with you ...
Last edited by john_tullamarine; 16th Apr 2002 at 06:53.