No prices there, but I like these bits:
Interesting stuff…
The cheapest way to access is the iPad app. I don’t use it but it us circa $1000/yr. https://www.flyapg.com/iPreFlight.aspx
Remember the point is not just to let you avoid hitting terrain, it may allow you to depart with higher payload if you have an emergency procedure which allows a lower gradient.
But you wouldn’t feel the need to follow a standard SID in case of OEI anyway, right?
Flyer59 wrote:
But you wouldn’t feel the need to follow a standard SID in case of OEI anyway, right?
Sure but you depart Geneva into IMC an lose and engine, you need a plan B if you can’t follow the SID climb gradient.
RobertL18C wrote:
w_n thank you, I assumed that % gradient was factored for wind (50% headwind, 150% tailwind) in the obstacle domain on departure to platform altitude as part of the NTOFP calculations. Factored ground speed would be used for any minimum % gradient requirement, and presumably 2nd segment one engine inoperative from the time of entering IMC?
In our operations manual (don’t know if that’s regulated differently with other companies) the factors for headwind and tailwind only apply to the takeoff and landing distance calculations up to second segment climb. Which means for example that for a 20kt headwind, only 10kt can be used in the calculation. Once past the second segment, actual winds can be used.
Sion must be climb limited mass for most commercial air transports?
Certainly. Sion and Lugano are very similar in terms of climb gradient (in the 13…15% range for some departures). Even if some aircraft can meet those gradients with all engines running (“my” Citation 560 should be able to exceed 20% at MTOM below FL100) I can’t imagine that there exists any civilian twin engined aircraft that is able to do 14% on one engine at 8000ft. Therefore, as others have written above, an escape procedure is required for those routes that covers the event of an engine failure. Our company also uses APG as a service provider for that. The cost is something like 80 Euros per month per aircraft if I remember correctly. APG provides the option to use the latest weather for the calculation which means that wind and temperature is always factured in.
Great informative post, what_next. Really interesting stuff. Many thanks.
What exactly do you get for your money? Do you get some sort of RNAV procedure, made up of waypoints which are loaded into the GPS as user waypoints, or have they done a deal with Jepp to merge their “custom SID” into the Jepp database?
Since the mountains don’t move, what stops somebody paying for the design just once?
Presumably if somebody ends up flying this “custom SID” (especially in IMC) then ATC needs to know, for separation purposes.
what_next wrote:
Our company also uses APG as a service provider for that.
How do you navigate in such a case?
One reason for the insane climb gradients in the Sion SID is apparently (or that seems to be the excuse FOCA states) GPS satellite signal obstruction in the valley. That is apparently also why there’s no SID along the valley (via Martigny to the Lake Geneva) (the other is that the valley is roughly 1 mile wide, so PRNAV isn’t good enough)
Presumably if somebody ends up flying this “custom SID” (especially in IMC) then ATC needs to know, for separation purposes.
They will have declared an emergency so not likely to be in doubt. It isn’t a custom SID it is an emergency procedure. It isn’t in the database but uses waypoints that are along with heading, tracks and conventional navaids.
By the way Jason, is there a legal procedure for a twin jet to take off on ONE engine? Like for repositioning to a shop I mean. (Was it done?).
Flyer59 wrote:
By the way Jason, is there a legal procedure for a twin jet to take off on ONE engine? Like for repositioning to a shop I mean. (Was it done?).
It is certainly not a permitted procedure and there is no performance data to be able to know how much runway would be required.
