OnCourse Software

PF3 determines TOD and tower hand-offs by way points...I have maintained since its release that this is not good...TOD, runway assignment, and tower hand-off should be determined solely by distance to airport, regardless of way points.

I just did a 7 hour simulation with the last way point very close to the destination. This is not negotiable because it is the airport's IAF, as determined by a real world flight planner. As a result, PF3 gave me TOD too late, and I never got the tower hand off or runway assignment.

People who buy this product do so because they prefer realism. It is highly distressing to to do everything correctly and still be the victim of improper procedure through no fault of our own.

This is not a complaint. This is an appeal to have PF3 re-written to determine descent profile solely by distance to airport only, to completely assure correct data in all simulation situations. In this one regard, the limited stock ATC never failed.

I believe that designers have a responsibility to insure that their clients are never confounded.

I am including the logs in the reply. If this was the result of pilot error, I will eat my hat!

debug log only

Well, only Dave can say for sure but I do not think a PF3 re-write will happen soon. The IAF is too close to the destination airport to be included in your PF3 flight plan. In fact, if your last waypoint is closer than 15 nm you should be given a warning when the flight plan is loaded (unless you disabled the warnings). You will probably get the best results when the last waypoint is between 25 and 40 nm out, although this can vary. Note that this does not prevent you from flying a real-world approach. If you select the option for cleared-to-finals at pilot’s discretion you can fly whatever real-world approach you wish, and enter the approach waypoints (including the IAF or an entire RNAV approach) in your FMC. If you forget to choose the STARs option before your flight, you can still hit hotkey 1 to request clearance at pilots’ discretion.

mllgrennman wrote:

PF3 determines TOD and tower hand-offs by way points...I have maintained since its release that this is not good...TOD, runway assignment, and tower hand-off should be determined solely by distance to airport, regardless of way points.

I just did a 7 hour simulation with the last way point very close to the destination. This is not negotiable because it is the airport's IAF, as determined by a real world flight planner. As a result, PF3 gave me TOD too late, and I never got the tower hand off or runway assignment.

People who buy this product do so because they prefer realism. It is highly distressing to to do everything correctly and still be the victim of improper procedure through no fault of our own.

This is not a complaint. This is an appeal to have PF3 re-written to determine descent profile solely by distance to airport only, to completely assure correct data in all simulation situations. In this one regard, the limited stock ATC never failed.

I believe that designers have a responsibility to insure that their clients are never confounded.

I am including the logs in the reply. If this was the result of pilot error, I will eat my hat!

TOD is calculated by distance to airport plus we use current speed and altitude in the algorithm

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Dan77 wrote:

Well, only Dave can say for sure but I do not think a PF3 re-write will happen soon. The IAF is too close to the destination airport to be included in your PF3 flight plan. In fact, if your last waypoint is closer than 15 nm you should be given a warning when the flight plan is loaded (unless you disabled the warnings). You will probably get the best results when the last waypoint is between 25 and 40 nm out, although this can vary. Note that this does not prevent you from flying a real-world approach. If you select the option for cleared-to-finals at pilot’s discretion you can fly whatever real-world approach you wish, and enter the approach waypoints (including the IAF or an entire RNAV approach) in your FMC. If you forget to choose the STARs option before your flight, you can still hit hotkey 1 to request clearance at pilots’ discretion.

As Dan says. The problem isn't with PF3 it's mostly with your fpl. You must remember that TOCs and TODs in your FMC are only advisory. In other words ATC decide when you descend. If as Commander you don't like it you can say so and ATC will usually comply. Which as Dan says PF3 mimics too.

Modify your fpl profile a little to get a better result. Oh, and if you were to fly from london to Northern Italy then ATC will always give you a very late clearance as you have to cross the Alps and then descend like a brick. So sometimes descending like a brick is real life! Into Torino for example you have 30 nm to get from FL210 to 6,000ft. It's quite fun to see the passenger's faces who have haven't flown that route before!

thank you for your replies...i will implement you suggestions...but just to add insult to injury...i did a replay right after landing to see my performance...i set the replay to 400 seconds with PF3 still running...and sure enough i got tower hand-off during the replay!

dmarch wrote:

TOD is calculated by distance to airport plus we use current speed and altitude in the algorithm

im wondering if this may need adjusting...TOD has been all over the place with the 3x1 rule since ive been using PF3

vololiberista wrote:

if you were to fly from london to Northern Italy then ATC will always give you a very late clearance as you have to cross the Alps and then descend like a brick.

You know my very next flight was from Stansted to Verona!

mllgrennman wrote:

vololiberista wrote:

if you were to fly from london to Northern Italy then ATC will always give you a very late clearance as you have to cross the Alps and then descend like a brick.

You know my very next flight was from Stansted to Verona!

A tip for working out TOD which I have used for many years. (distance to go-12)*3. Invariably one has to slow down either during the descent or upon arrival at the lower altitude. Hence the deduction of 12 nautical miles to account for slowing down.
Distance to go 82nm-12=70. 70*3=210 =FL210. Though not for the arrivals as mentioned here!!