F100 - Overshot Runway at Newman Airport (9/1/2020)
You're confusing pre dispatch with post dispatch. Post dispatch you are using whatever approved system you have available which may even have the 15% factor built in them.
The pre dispatch 1.67 figures are off the maximum braking performance of the aircraft. You couldn't factor 67% on a normal everyday landing performance you'd need 3500m+ everywhere you went.
The pre dispatch 1.67 figures are off the maximum braking performance of the aircraft. You couldn't factor 67% on a normal everyday landing performance you'd need 3500m+ everywhere you went.
Curtain Twitcher, that's not a new instrument, it's only a CAAP. Essentially, nothings changed except that there is now a para on "very wet" landings.
IMO the fundamental flaw in all of this was the LDR change from +67% of demonstrated/actual to +15% just because you're now airborne (11.2 and it's Note). A bit like the old 45min FR for planning verses 30min FR after you get going. Illogical.
15% was always going to cause grief, and will continue to do so until somebody steps up and says the current rules are "an ass" and slaps some additional buffers on. Personally, if I don't have full preflight factors (1.67 or 1.92), even when airborne, I'm not doing it unless I'm in dire straits.
IMO the fundamental flaw in all of this was the LDR change from +67% of demonstrated/actual to +15% just because you're now airborne (11.2 and it's Note). A bit like the old 45min FR for planning verses 30min FR after you get going. Illogical.
15% was always going to cause grief, and will continue to do so until somebody steps up and says the current rules are "an ass" and slaps some additional buffers on. Personally, if I don't have full preflight factors (1.67 or 1.92), even when airborne, I'm not doing it unless I'm in dire straits.
There appears to be confusion about definitions. Have a look at Hamilton Island and tell me how anyone in an airliner can dispatch there with a 1.67 factor and what sort of performance is needed to make the factoring work.
The factor could be 1.92 for the 'dispatch' maximum weight!
I can't work out why s 11.1(b) of CAO 20.7.1B makes specific provision for the wet destination runway scenario for the 'dispatch' maximum weight but s 11.2 does not for the 'in air' calculation. If you know, before you take off, that the destination runway is or may be wet, the maximum take off weight has to be calculated on the basis that the landing distance required will be 1.92 times the distance required to land in the dry and, apparently, that requirement applies irrespective of whatever landing distance data has been supplied by the holder of the type certificate for the aircraft. However, once the actual destination conditions are known the factor changes to 1.67 or, in the case of an aircraft whose type certificate holder has supplied actual distance data, 1.15. Whattha?
If the actual conditions on arrival turn out to be wet as forecast, what magic changes the risk from one requiring a 1.92 factor to 1.67 or 1.15 factor in the same aircraft?
I can't work out why s 11.1(b) of CAO 20.7.1B makes specific provision for the wet destination runway scenario for the 'dispatch' maximum weight but s 11.2 does not for the 'in air' calculation. If you know, before you take off, that the destination runway is or may be wet, the maximum take off weight has to be calculated on the basis that the landing distance required will be 1.92 times the distance required to land in the dry and, apparently, that requirement applies irrespective of whatever landing distance data has been supplied by the holder of the type certificate for the aircraft. However, once the actual destination conditions are known the factor changes to 1.67 or, in the case of an aircraft whose type certificate holder has supplied actual distance data, 1.15. Whattha?
If the actual conditions on arrival turn out to be wet as forecast, what magic changes the risk from one requiring a 1.92 factor to 1.67 or 1.15 factor in the same aircraft?
......yeah, and that messed with my fragile mind too, but I figured Bloggs may have just been drinking a lot before posting.
In what aircraft? Are you saying every aircraft’s landing performance is predicated on max braking effort? Because you’re very wrong.
If a manufacturer has provided inflight landing distance figures, these are not just based on 50ft/max effort so 15% is considered an acceptable buffer.
Originally Posted by Morno
And for dispatch that’s fine, but I’m sure as **** not going to use 167% while I’m in the air like you said you would.
Originally Posted by Morno
Are you saying every aircraft’s landing performance is predicated on max braking effort? Because you’re very wrong.
Originally Posted by Student in Debt
If a manufacturer has provided inflight landing distance figures, these are not just based on 50ft/max effort so 15% is considered an acceptable buffer.
A request:
Run Flysmart in the pre-dispatch scenario to say Hamilton Island and advise the landing weight allowed.
Then run Flysmart in the in-flight scenario and advise the weight allowed.
Run Flysmart in the pre-dispatch scenario to say Hamilton Island and advise the landing weight allowed.
Then run Flysmart in the in-flight scenario and advise the weight allowed.
Originally Posted by Studentindebt
You’d have to look that up for your aircraft type, if the information is provided, as it varies depending on the assumptions the manufacturer makes.
Landing is pretty standard: threshold at 50ft at VRef, 7 seconds to touch down then max braking with full reverse to a stop. What other things will make "15% an acceptable buffer" [your words]?
50ft, 7 seconds, landing conditions as entered, braking according to chosen method (autobrake/manual-max braking/reverse), reported braking action taken into account. 15% on top of that figure. As the PIC you are free to use whatever figure you like as a buffer if you feel it is appropriate, just as you can opt to use a higher landing minima than say 200ft/550M.
Given the thread is about an aeroplane that ran off the end in the wet, your choosing of the desired braking "method" to increase the buffer is irrelevant. Obviously, we're talking about a max-braking landing with only 15% buffer.
IFLD figures are there to provide guidance on the actual level of performance available given the conditions and take account of runway condition. So the braking method chosen is not irrelevant, one could calculate the distance required with autobrake 2/low and find that even on a contaminated runway there is sufficient LDA with the 15% margin applied.