Cat A Offshore Helideck procedure of AW139
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Cat A Offshore Helideck procedure of AW139
I wonder if we are able to do Part E and I, Offshore Helideck procedure at the elevated Helideck on the land.
The name of the procedure is Offshore Helideck but Maximum Altitude for Offshore Helideck CAT A Take-Off as well as Landing is 5000 ft Hp/Hd.
I don't think there is such a high Offshore helideck and I think the procedure above mentioned is not only for real offshore helideck.
The only problem I have now is that there is the description on Part E Page S12-E5 as below;
If the Take-Off Weight would require a drop down, during a single engine failure, it is assumed that the height of the Elevated Helideck
is greater than the Drop Down plus a height clearance margin as required by the Competent Authorities, and that there are no obstacles
beyond and below the deck edge.
The name of the procedure is Offshore Helideck but Maximum Altitude for Offshore Helideck CAT A Take-Off as well as Landing is 5000 ft Hp/Hd.
I don't think there is such a high Offshore helideck and I think the procedure above mentioned is not only for real offshore helideck.
The only problem I have now is that there is the description on Part E Page S12-E5 as below;
If the Take-Off Weight would require a drop down, during a single engine failure, it is assumed that the height of the Elevated Helideck
is greater than the Drop Down plus a height clearance margin as required by the Competent Authorities, and that there are no obstacles
beyond and below the deck edge.
The limit states 5000ft hp or hd. You could get to 5000 ft Hd (density altitude) in a 50 Deg Celsius OAT with a relatively high humidity at sea level. I suspect that's what that limitation is about. Not sure I understand the remainder of your query.
I’ve never seen humidity in a performance graph?
Fair point. Whilst it does have an effect, the certification specifications (CS-27/29) do not require it to be considered. It was historically considered when performance margins were tighter
Pprune discussion - humidity and density altitude
Pprune discussion - humidity and density altitude