Flight time accuracy?

Pro Member First Officer
Jim Lapinsky (7ECA-Captain) First Officer

I flew a trip yesterday from airport A to B. Today I flew the return. Yesterday the flight was 2.9 hrs today it was 5.5 Both flights were in fair weather and the exact same distance flown? As I am keeping a log book this difference of 2.6 hours seems way off. Am I expecting too much from FSX with realistic flight times? Or are they just general and not consistent? It would seem the times of the trips should be about the same for both legs excluding winds aloft or weather factors. 🙄

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Pro Member Chief Captain
CRJCapt Chief Captain

That's strange.
1. Was the altitude the same?
2. Was the IAS the same?
3. Was the OAT the same?

Pro Member First Officer
Jim Lapinsky (7ECA-Captain) First Officer

Not really. Other than an enroute cruise altitude of 10,500 to A and 9000 on the return flight to B. There were some other slight variations, but given overall calm weather and distance factors. The descrepency seems pretty large... almost double the time for two almost identical flights. The first was in real weather and IFR but would that make that much difference make sense? I have seen some odd addition errors in the flight log ex: 2.7 + 5.3 = 8.1 ?? I'm not sure where FSX got the extra .1 and over say a thousand hours this might be a significant error.

Pro Member First Officer
Jim Lapinsky (7ECA-Captain) First Officer

Yes they do...

I am an ex military pilot as well a currently licenced as a commercial pilot so I am well aware of weather factors. Given almost the same flight conditions a few thousand feet wouldn't account for almost double the flight time? I could see a variation if I had head or tail winds aloft, but in fair weather conditions the flight times should be fairly close both ways. But then maybe it was uphill one way and down the other? Wink I'm assuming I shouldn't fret about the accuracy of FSX as compared to the real world as it is a game... It just seemed odd. There are other strange things in the logbook section with addition and such, but I guess I'm expecting too much from the game. Kinda hard to keep accurate records, but them there's a reason FSX isn't approved as a simulator for actual flight simulation requirements. Best keep those hours out of my real log book.

Pro Member First Officer
mdaskalos First Officer

7ECA-Captain wrote:

I have seen some odd addition errors in the flight log ex: 2.7 + 5.3 = 8.1 ?? I'm not sure where FSX got the extra .1 and over say a thousand hours this might be a significant error.

That one's probably due to rounding of displayed digits. Suppose the aforementioned log entry, if carried out to two digits, was

2.74+5.34=8.08.

rounding everything to one gives you what you see in the log, and it is "correct."

mdaskalos

Pro Member First Officer
Jim Lapinsky (7ECA-Captain) First Officer

I Guess... 2.3 + 5.7 = 8.1 ?? I've always thought that it didn't go beyond the first decimal point which should have made the flight time a total of 8.0 In recording real log book times each hour is divided into tenths, or six minute increments so 1.1 would be 1 Hour, 6 minutes. This is standard to all aviation and I assumed that it would also hold for FSX.

Pro Member Captain
acepilot32 Captain

my FSX is pretty dumb it says in the rewards iv ranked 20 hrs. in multi jet and 20hrs. in single prop.

the funny thing is i dont even play FSX that much to rank up almost 40-80hrs of flight time.

Pro Member First Officer
Jim Lapinsky (7ECA-Captain) First Officer

Yeah, maybe I'm expecting too much out of FSX. It might be I need to make some big adjustments between my real world flight experiences and the sim. 🙄

Pro Member First Officer
mdaskalos First Officer

7ECA-Captain wrote:

I Guess... 2.3 + 5.7 = 8.1 ?? I've always thought that it didn't go beyond the first decimal point which should have made the flight time a total of 8.0 In recording real log book times each hour is divided into tenths, or six minute increments so 1.1 would be 1 Hour, 6 minutes. This is standard to all aviation and I assumed that it would also hold for FSX.

FSX is a computer program and it handles numbers in a fashion similar to other computer programs. Have you ever used Excel??? Try the following exercise.

Enter 10/3 in three cells. In a fourth cell add the total of those three. Format the cells to a single decimal place. What is the displayed result?

Expressed as a conventional math problem with a single decimal place for all numbers, it would be:

3.3+3.3+3.3=10.0

Excel will display it that way all the way out to the maximum of 30 digits.

Enter 3.333 directly three times instead of the fraction, and it will do the same through two digits of precision.

So 2.3+5.7=8.1 ?? Absolutely, when a computer is adding the entirety of a number and you're only seeing a single digit of precision.

And trust me, this is common to a variety of programs that handle numbers. It just happens that you take offense at it happening at the one-decimal-place level.

Excel, (probably Microsoft Works), FSX, etc. - they all round the display of the number - not the number itself.

Of course, if you want to be FAA-accurate, you could copy and paste the raw flight times in single digit precision to a text editor, save it, copy that and paste it back into the logbook, and then they're true single digit numbers, and then everything should work as you like. But everyone seems to think FSX has enough computational overhead as it is, so...

mdaskalos

Pro Member First Officer
Jim Lapinsky (7ECA-Captain) First Officer

Ahh.. Well that is why they invented to old paper log book. And the sim can't suddenly loose all your hard earned flight times. About $7.00 and kinda fun to log your hours in an old fashioned book. I don't trust computerized flight log book in the real world either.

Pro Member First Officer
oldsamer First Officer

Remember this is a computer simulation (sim). There are two or three "FEATURES" available in this sim that would cause this annomaly.

Are you saving your flight then continuing it at a later time? Say you save and exit FSX at 1440 21Jan08 and continue it at 0800 23Jan08. Depending on if the flight was saved as [default flight] it will reset the mission clock to real time [current date and time]. But, if this flight is not [default flight] then previous saved flight clock is loaded (you're not playing in real time).

Simulation rate can compound the annomly of [current date and time] vs saved mission clock because sim rate effects mission clock but not [current date and time].

Saving a flight also effects the log book. This can be seen after a mid flight save in Esc/flight analysis where the recorded flight track is erased, effectively begining a new mission recording.

Pro Member First Officer
Jim Lapinsky (7ECA-Captain) First Officer

I always fly one mission one way at the least. I don't save missions as a rule, but Given FSX is a sim one shouldn't worry too much about the accuracy. I have started to use a pilots log book for fun and to prevent loss of the hours. Pointless to keep a paper log, maybe but it adds to the realism and it's neat to look back at the flights and hours. That way it's no big deal if say you need to reload the game as you don't loose the hours. I also like to dump the logs once in a while to free up memory.

Pro Member First Officer
Jim Lapinsky (7ECA-Captain) First Officer

Hmm, Yesterday I flew a trip with a total leg of 4.5 hours. I kept the sim running while I refueled and restarted the engines, then made the return. The log book showed the outgoing flight as 4.5, and a separate entry for the return leg with a total of 9 hours? It seems the second entry combined the first and second flights?

Pro Member First Officer
lionlicker First Officer

Possible explaination for your phenonema is that you are travelling with the sun on the way, and returning against the sun on the return. Remember as you pass through time zones the hour will skip ahead or skip backwards.

I have found the time accuracy to be excellent and consistent in this sim.

Pro Member First Officer
Jim Lapinsky (7ECA-Captain) First Officer

Hmmm, Ok... But for a three hour local flight??? I admit I'm a little doubtfull. Ok a lot. 😉

Pro Member First Officer
mdaskalos First Officer

7ECA-Captain wrote:

Hmm, Yesterday I flew a trip with a total leg of 4.5 hours. I kept the sim running while I refueled and restarted the engines, then made the return. The log book showed the outgoing flight as 4.5, and a separate entry for the return leg with a total of 9 hours? It seems the second entry combined the first and second flights?

Perhaps you have found the cause of your original problem.

Do the same kind of thing again, but back it up with a stopwatch at your side, for a short flight

Pro Member First Officer
Jim Lapinsky (7ECA-Captain) First Officer

Yeah in a weird way it makes sense, not good sense mind you... but I think that it might just be what happened...

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