OnCourse Software

3/1 rule says I should be at 10,000 ft 30 miles out....lets go with that for a second....So if my last waypoint is 30 miles from destination...all I have to do is make that waypoint 10,000 ft in the planner?

Will PF3 make sure I'm at 10.000 ft when I reach it...or will it tell me to go down to 10,000 ft once I get there...

mllgrennman wrote:

3/1 rule says I should be at 10,000 ft 30 miles out....lets go with that for a second....So if my last waypoint is 30 miles from destination...all I have to do is make that waypoint 10,000 ft in the planner?

Will PF3 make sure I'm at 10.000 ft when I reach it...or will it tell me to go down to 10,000 ft once I get there...

Just make sure that the waypoints step down in a manner that is both acceptable to the aircraft's performance and meets any altitude constraints. Enter the FAP of the destination airport in the SIDs STARs page. The problem is this- a flight plan generator will often determine by itself a TOD. You enter that into an FMC and it too will often come up with another TOD. You have to remember that the "3/1 rule" isn't a "rule" it's a rule of thumb! ATC can and do at any time delay your descent if they see fit. All TOD is, is an "optimal" descent profile for your a/c with regard to its performance and weight. Of course PF3 will, left to its own devices come up with its own profile which is usually quite accurate but the waypoint adjustment page allows you to tailor that to actual constraints etc.

When contructing a flightplan I personally use Routefinder/Online Flight Planner. I then adjust it for any known issues and I usually end up with an accurate flightplan and profile. On the other hand what I have seen of PFPX makes me wonder what algorithm they use. When I have seen online streamers use it PFPX consitently comes up with very strange and unflyable results.

mllgrennman wrote:

3/1 rule says I should be at 10,000 ft 30 miles out....lets go with that for a second....So if my last waypoint is 30 miles from destination...all I have to do is make that waypoint 10,000 ft in the planner?

Will PF3 make sure I'm at 10.000 ft when I reach it...or will it tell me to go down to 10,000 ft once I get there...

Waypoint altitudes from external "planner" software are not stored in the flight plan, only the cruise altitude.
PF3 calculates waypoint altitudes according to the aircraft profile. These should already work fine, but you can adjust them on the adjustment page, e.g. to match them to real-world altitudes from the charts for the corresponding waypoints.

PF3 tries to make sure you are at 10.000 ft when you reach a waypoint that is set to 10,000 ft. The only time this can't work is if you have two waypoints close to each other and manually set altitudes that are too different.
The only problem with this that I have personally experienced is, when I miss a waypoint and PF3 switches to the following waypoint too late, the descent instructions came too late. But I think Dave made PF3 detecting missed waypoints much earlier now. There have been other bugs and corresponding fixes for this during the recent releases, which I did not experience myself, because they were only triggered in specific constellations, so if you think you found a problem, please report it here with the corresponding logs.

vololiberista wrote:

On the other hand what I have seen of PFPX makes me wonder what algorithm they use. When I have seen online streamers use it PFPX consitently comes up with very strange and unflyable results.

Please let's not dilute this thread with bashing of software based on the usage you have seen from certain people. I'm sure they would be able to create equally unsuitable flight plans with e.g. routefinder, if routefinder would have the flexibility to shoot yourself in the foot.

ThomasAH wrote:

vololiberista wrote:

On the other hand what I have seen of PFPX makes me wonder what algorithm they use. When I have seen online streamers use it PFPX consitently comes up with very strange and unflyable results.

Please let's not dilute this thread with bashing of software based on the usage you have seen from certain people. I'm sure they would be able to create equally unsuitable flight plans with e.g. routefinder, if routefinder would have the flexibility to shoot yourself in the foot.

We each of us use the software that we prefer. You are the one saying that I am "bashing"! I am nevertheless entitled to an opinion Thomas. And for payware PFPX does not appear to "consitently" reproduce flightplans accurately. I know that you use it and apparently for you it works ok. If you are happy that it produces acceptable flightplans that are also real life then that's great. Perhaps I apply more stringent real life tests when creating a valid fpl rather than excepting what is generated as a given!

PF3 brings me down 100 miles too soon most of the time...Once with a GA aircraft at FL 220 I got TOD an hour away from destination!
I use the default flight planner...I've tried making the last waypoint before destination 30 miles out and programmed PF3 to 10000 ft at that point...No luck...

mllgrennman wrote:

PF3 brings me down 100 miles too soon most of the time...Once with a GA aircraft at FL 220 I got TOD an hour away from destination!
I use the default flight planner...I've tried making the last waypoint before destination 30 miles out and programmed PF3 to 10000 ft at that point...No luck...

As usual: Logs or it did not happen
You could be right and PF3 wrong, or maybe you didn't notice an "at pilot's discretion".

sorry about not getting you the logs sooner...i keep doing flights and they get overwritten...ill get the next one out when it happens again...thanks

im going to do a baseline flight to test the TOD issue...what should the ideal parameters be? Flight level, distance, cruise speed...number of waypoints...please let me know...

mllgrennman wrote:

im going to do a baseline flight to test the TOD issue...what should the ideal parameters be? Flight level, distance, cruise speed...number of waypoints...please let me know...

Without your intended route that's diffiicult. As said the TOD is something calculated by the aircraft software as the optimum point. It is rarely written into the flightplan though it can be to a degree (forgive the pun). For example

Quote:

UL615 PZ493 UT939 C/45N012WF140F240

This is where I expect/wish to be at cruise. Note that it is only to the nearest degree of lat and long. So it's not accurate being out by up to 60nm! It is therefore only a guide for ATC. In real life ATC will help you start your descent in the area of the "TOD" if possible. But their main overriding concern is to have you at the correct altitudes for various constraints and traffic. So your fpl in PF3 must mimic that. Work backwards from known altitude constraints to your cruise altitude. Your cruise altitude is of course based on overall distance and a/c performance and weight. So from your first altitude constraint work back considering the best descent profile. That depends on how many waypoints you have also. Long haul flights will often have an initial shallow descent allowing them to maintain a high ground speed etc. Other times like crossing the Alps and landing in Northern Italy requires a rapid descent with all the washing hanging out.
Left entirely to its own devices PF3 does a not to bad a job at creating a profile. Using the waypoint adjustment page allows you to tweak that a bit more.
To give a couple of quick examples
ZJSY-->VHHX starting at cruise RAGSO FL240 -->CHALI FL160 -->CH 8,000ft. That is an example of a shallow descent
EGKK-->LIMF starting at cruise MILPA FL370 -->LURAG FL130-->VEROB FL60. An example of a rapid descent. If you plan your flight carefully TOD should not be a major issue. Your focuas is your overall descent profile to get you down to the constraints in a safe manner.