Net flight path obstacle clearance
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Net flight path obstacle clearance
As my sources are contradictory, I'm turning to you guys for help...
Take-off on a wet RWY with an engine failure at Vef. How much obstacle clearance will your NET flight path provide?
The Jepp ATPL book, together with the NAVTECH aircraft performance manual, claims that both the gross and net flight paths diverge beginning from the same point... In the case of the wet RWY at the screen height of 15'. So your obstacle clearance provided by the net flight path would be 15'.
On the other hand, the "Getting to grips with A/C performance" by Airbus and JAR OPS 1.495 claim that, whatever the screen height may be, the net flight path always starts at 35' and maintains at least 35' of obstacle clearance at all times.
On a wet RWY, this means that the gross flight path may start at 15', while the net starts at 35'... in which case the gross flight path starts 20' below the net.
I hope someone here can put this issue to rest...
Thanks.
Take-off on a wet RWY with an engine failure at Vef. How much obstacle clearance will your NET flight path provide?
The Jepp ATPL book, together with the NAVTECH aircraft performance manual, claims that both the gross and net flight paths diverge beginning from the same point... In the case of the wet RWY at the screen height of 15'. So your obstacle clearance provided by the net flight path would be 15'.
On the other hand, the "Getting to grips with A/C performance" by Airbus and JAR OPS 1.495 claim that, whatever the screen height may be, the net flight path always starts at 35' and maintains at least 35' of obstacle clearance at all times.
On a wet RWY, this means that the gross flight path may start at 15', while the net starts at 35'... in which case the gross flight path starts 20' below the net.
I hope someone here can put this issue to rest...
Thanks.
I believe source 2 is correct---because the 15' scren height is for when TODA limits TO on the wet RWY---but [from my rules FAR 135]
on must pass all at least 35' vertically and at least 200' horizontally--with in arpt boundaries and at least 300' horizontally outside---and then maintain a specified gradient above the obstacle plane---which is reduced by a certain margin [or increased--I guess it depends on the point of view
]---since obstacle clearance requirements must be fulfilled in all cases--- if obstacles were limiting then deference has to be made to that and I never seen an AC or such that contravenes that---I'm not a perf expert but that's my take---if I'm not correct---I'm sure I'll find out soon
PA
on must pass all at least 35' vertically and at least 200' horizontally--with in arpt boundaries and at least 300' horizontally outside---and then maintain a specified gradient above the obstacle plane---which is reduced by a certain margin [or increased--I guess it depends on the point of view
]---since obstacle clearance requirements must be fulfilled in all cases--- if obstacles were limiting then deference has to be made to that and I never seen an AC or such that contravenes that---I'm not a perf expert but that's my take---if I'm not correct---I'm sure I'll find out soonPA
