Originally Posted by
737 Driver
In the NTSB briefing (link posted above) it was stated that the available landing distance for this runway was 7800 feet. At maximum landing weight on a wet grooved runway, a 737NG will require approximately 6800 feet of runway with both reversers, Flaps 30, max braking (air distance included). On a wet ungrooved runway (braking advisory medium), the calculated landing distance exceeds 8,300 feet. If braking action was medium to poor, the calculated distance exceeds 9500 feet. To be fair,
Thanks, a wealth of information.
I am looking specifically at the choices done w.r.t. the landing performance before accepting the destination. It's a pet subject this year. I think that after harmonization the rules are similar on both sides of the Atlantic.
Somebody correct me:
- Flight test data are no longer legally approved to be used operationally
- FCOM Perf data are now "Operational Landing Distance" = OLD = Flight test + 10%
- Wet distances typically carry another 15% penalty unless flight tested.
Legal requirement before dispatch: Regulatory Landing Distance
= RLD = OLD + 67%
--> now, here you can cheat around tailwind claiming landing will be on the runway into the wind (*)
--> whether the TAF shows relevant precip at time of landing is debatable. Especially if delayed, it is still a must pass check at dispatch.
Legal requirements before landing: Actual Landing distance [A commander shall ensure himself by a reasonable means that landing can be accomplished within LDA - not an exact quote but close enough]. And the expected landing distance is the
= OLD (see above) or, in some jurisdictions
= Factorized LD = FLD = OLD + 15%
--> here you definitely cannot cheat around present tailwind
--> here you definitely cannot cheat around wet (real achieved BA is still guesswork though)
Observe, that for
low visibility and inclement weather:
- Everybody knows not to descend without visual reference below DH.
- Everybody knows there's approach ban altitude limit.
- Everybody knows that sometimes you cannot even depart due to destination WX.
--> and these rules serve the industry well, having been put in place for a great number of very tragic reasons.
We have exactly the same tools available for runway overruns.
- Do not land beyond the distance marking stripes (if painted properly
**)
- If the in-flight calculation OLD or FLD is not satisfied, landing is not authorized
- If the dispatch calculation RLD is not satisfied, the flight shall not commence.
--> are we using these tools properly to make sure we do not paint ourselves into a Human Factors corner?
--> is there some point in the chain of events in this accident, where it should not have been allowed to unfold - if the job was done by the book given what is written already?
737 Driver Similar to your assessment of the MCAS issue I think we have the responsibility to G/A and not land deep. Clean our side of the street.
Also, it is inevitable on a global scale that due to unfortunate reasons a good number of us won't on a bad day. Whether or not I will fall into the second pool when Reaper comes knocking is badly predictable (
wonkazoo's experience explains).
So are there any stops, barriers or fences that I may have crossed even unknowingly? I think there are already sufficient tools, and wait in anticipation for the Burbank SWA report to read what was the legal authority to attempt that landing at all.
Kind regards, FD.
SWA 737 overrun at BUR - Dec 6 2018 anyone cares to do similar view for this latest one?
* = NOT IN THE BURBANK CASE
** = NOT IN THE BURBANK CASE