Help Needed: Two Calculation Problems

[Rich S]

Howdy, howdy:

I have two calculation problems that are severely testing my last few brain cells; please refer to the attached.

In the Trip Results box, I summarize some of the calculations in the Flight portal--one of them is average speed of the flights entered in the portal. The calculations (number) are:

Total_Trip_Time = Sum(Flight_Data::Time_Leg)

Total_Distance_Flown = Sum(Flight_Data::Distance_Flown)

Average_Speed = Total_Distance_Flown / Total_Trip_Time

As shown, Total_Trip_Time = 2.0 and Total_Distance_Flown = 34; both of these are correct. However, Average_Speed = 16.8. How on Earth did FM come up with that? It should be 17.0.

The next question revolves around the Time_on_Engine field. The three-legged trip starts at 1110.0 and ends at 1116.0, so the total time is 5.0 hours; how do I code a calc to obtain that? I imagine I need to use GTRR, but I'm not sure.

As always, your help is greatly appreciated.

Cheers!

Rich

[mr_vodka]

My guess would be it has something to do with your time enroute calc field. You most likely have it set up to display to the tenth of a place but there is most likely more digits beyond it. So the total time is probably 2.02 or soemthing like that.

As for your time engine you could use a calc such as,

Max(Flight_Data::Engine_End) - Min(Flight_Data::Engine_Start)

P.S. put in checks to make sure that the fields are not empty so that you dont get unwanted results.

[comment]

1. John's guess is correct: your total time is actually 2:01 (2.0166666666666667 in decimal hours).

34 / ( 2 + 1 / 60 ) = 16.859504132231405

2. Another way would be:

Last ( Flight::EngineEnd ) - Flight::EngineStart )

assuming the records are entered in order, or that the relationship is sorted.

[Rich S]

Thanks, Mr. V and Comment! The engine calc works like a charm.

As for the Time-Distance-Speed calcs, I tweaked the calcs by using the Round command( e.g., Round(Sum(Flight_Data::Time_Leg);1)) to clear things up.

Thanks for the suggestion, too--it's a good one.

Edited May 15, 2008 by Guest
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