How do you guarantee finding that airport

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PilotDAR
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Re: How do you guarantee finding that airport

Post by PilotDAR »

30 degrees off at 30 minutes out means 20 minutes extra flying
I have trouble telling time to within a minute, so flying to within a degree of heading is outside my worry zone entirely!
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photofly
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Re: How do you guarantee finding that airport

Post by photofly »

Ha ha... my geometry was off. It's actually 21.9 minutes extra flying time. 20 minutes is still close enough for rock and roll though. It breaks down as 4.6 minutes extra to reach the river, then 17.3 minutes tracking along the river.

(Why ? A triangle with interior angles of 30°, 60° and 90° has sides in the ratios 1: √3/2 : 1/2. The original track length flown from the point of turning was the side of √3/2. The new length is the sum of the other two sides, which is 1+1/2 = 3/2, which is longer by a factor of (3/2 - √3/2 ) ÷ √3/2 = √3 - 1 = 0.73. The original track time was 30 minutes, so the new track is longer by 0.73 * 30 = 21.9 minutes)
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AirFrame
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Re: How do you guarantee finding that airport

Post by AirFrame »

photofly wrote: Wed Jan 02, 2019 8:06 pm Ha ha... my geometry was off. It's actually 21.9 minutes extra flying time. 20 minutes is still close enough for rock and roll though. It breaks down as 4.6 minutes extra to reach the river, then 17.3 minutes tracking along the river.
Don't forget you'll save a few minutes making the turn, which rounds the sharp corner at the river between the hypotenuse and the short leg of the triangle. So 20 minutes probably *is* close enough.
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Re: How do you guarantee finding that airport

Post by Redneck_pilot86 »

If you don't know where you are, how do you know when you are 30 minutes back to execute your hail mary turn?
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photofly
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Re: How do you guarantee finding that airport

Post by photofly »

Um... even student pilots should know the appropriate answer to that question.
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geneticistx
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Re: How do you guarantee finding that airport

Post by geneticistx »

Who is flying with just paper these days? get an app. use the "extend the centre line" option.
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iflyforpie
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Re: How do you guarantee finding that airport

Post by iflyforpie »

Redneck_pilot86 wrote: Thu Jan 10, 2019 4:05 am If you don't know where you are, how do you know when you are 30 minutes back to execute your hail mary turn?
I guess that’s the problem with using GPS/FMS all the time rather than the old ground speed and clock method.
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Re: How do you guarantee finding that airport

Post by iflyforpie »

On a more serious note, I tried that method once on a low level navigational exercise, and wound up getting more lost. I actually wound up north of an airport deep in the Snake River canyon (Oxbow Airport) rather than south of it like I thought because of a combination of things.

If it were me, I’d continue as per my nav log on the heading I’d calculated until my elapsed time, and then I’d look or make an educated guess at where the airport is. After that, do a precautionary.
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anofly
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Re: How do you guarantee finding that airport

Post by anofly »

This "deliberate cross track error" is how Amelia Earhart flew looking for her island.I believe she flew to meet her "longditude line" well north of her desired position, as Longditude was easier to establish than lattitude with the instruments of the day.She then likely turned south and went looking for her island , that sadly she did not locate...
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Re: How do you guarantee finding that airport

Post by pelmet »

iflyforpie wrote: Wed Jan 16, 2019 11:15 am On a more serious note, I tried that method once on a low level navigational exercise, and wound up getting more lost. I actually wound up north of an airport deep in the Snake River canyon (Oxbow Airport) rather than south of it like I thought because of a combination of things.

If it were me, I’d continue as per my nav log on the heading I’d calculated until my elapsed time, and then I’d look or make an educated guess at where the airport is. After that, do a precautionary.
It would clarify things for us if you told us what the combination of things were.
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Re: How do you guarantee finding that airport

Post by Redneck_pilot86 »

iflyforpie wrote: Wed Jan 16, 2019 10:52 am
Redneck_pilot86 wrote: Thu Jan 10, 2019 4:05 am If you don't know where you are, how do you know when you are 30 minutes back to execute your hail mary turn?
I guess that’s the problem with using GPS/FMS all the time rather than the old ground speed and clock method.
So there is a pilot out there who can successfully calculate their groundspeed, yet still not know where they are along a planned track? I've never understood the type of person who would navigate by map without following the bloody map. I have no problem flying without a GPS, but if I am, I will have a map on my lap and know my position within a mile or so at all times. I guarantee the above scenario wouldn't happen to anyone properly navigating this way.
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Re: How do you guarantee finding that airport

Post by AirFrame »

geneticistx wrote: Sat Jan 12, 2019 10:08 pm Who is flying with just paper these days? get an app. use the "extend the centre line" option.
You won't need to "extend the center line" if you have an app. You'll know where you are. And if the GPS has failed or won't lock on, extending the center line won't help you... It's no better than a paper map at that point.
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Re: How do you guarantee finding that airport

Post by Old Dog Flying »

TRY Navigating..watch , map , ground.always worked for me. If you are using a handheld GPS try carrying a fresh set of batteries with you along with a current chart.
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Re: How do you guarantee finding that airport

Post by iflyforpie »

Redneck_pilot86 wrote: Mon Jan 21, 2019 3:28 pm
iflyforpie wrote: Wed Jan 16, 2019 10:52 am
Redneck_pilot86 wrote: Thu Jan 10, 2019 4:05 am If you don't know where you are, how do you know when you are 30 minutes back to execute your hail mary turn?
I guess that’s the problem with using GPS/FMS all the time rather than the old ground speed and clock method.
So there is a pilot out there who can successfully calculate their groundspeed, yet still not know where they are along a planned track? I've never understood the type of person who would navigate by map without following the bloody map. I have no problem flying without a GPS, but if I am, I will have a map on my lap and know my position within a mile or so at all times. I guarantee the above scenario wouldn't happen to anyone properly navigating this way.
What if you're over water? Or at night? It's not likely that you're going to know your exact cross track position, but you likely know your distance/time to destination.

Thus, 30 min to ETA, make your turn.
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iflyforpie
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Re: How do you guarantee finding that airport

Post by iflyforpie »

pelmet wrote: Fri Jan 18, 2019 1:46 pm
iflyforpie wrote: Wed Jan 16, 2019 11:15 am On a more serious note, I tried that method once on a low level navigational exercise, and wound up getting more lost. I actually wound up north of an airport deep in the Snake River canyon (Oxbow Airport) rather than south of it like I thought because of a combination of things.

If it were me, I’d continue as per my nav log on the heading I’d calculated until my elapsed time, and then I’d look or make an educated guess at where the airport is. After that, do a precautionary.
It would clarify things for us if you told us what the combination of things were.
Low level obstacles and high winds.
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Redneck_pilot86
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Re: How do you guarantee finding that airport

Post by Redneck_pilot86 »

iflyforpie wrote: Tue Jan 22, 2019 5:41 pm
Redneck_pilot86 wrote: Mon Jan 21, 2019 3:28 pm
iflyforpie wrote: Wed Jan 16, 2019 10:52 am

I guess that’s the problem with using GPS/FMS all the time rather than the old ground speed and clock method.
So there is a pilot out there who can successfully calculate their groundspeed, yet still not know where they are along a planned track? I've never understood the type of person who would navigate by map without following the bloody map. I have no problem flying without a GPS, but if I am, I will have a map on my lap and know my position within a mile or so at all times. I guarantee the above scenario wouldn't happen to anyone properly navigating this way.
What if you're over water? Or at night? It's not likely that you're going to know your exact cross track position, but you likely know your distance/time to destination.

Thus, 30 min to ETA, make your turn.
If you're over water, how do you calculate your groundspeed?
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Re: How do you guarantee finding that airport

Post by pelmet »

iflyforpie wrote: Tue Jan 22, 2019 5:47 pm
pelmet wrote: Fri Jan 18, 2019 1:46 pm
iflyforpie wrote: Wed Jan 16, 2019 11:15 am On a more serious note, I tried that method once on a low level navigational exercise, and wound up getting more lost. I actually wound up north of an airport deep in the Snake River canyon (Oxbow Airport) rather than south of it like I thought because of a combination of things.

If it were me, I’d continue as per my nav log on the heading I’d calculated until my elapsed time, and then I’d look or make an educated guess at where the airport is. After that, do a precautionary.
It would clarify things for us if you told us what the combination of things were.
Low level obstacles and high winds.
I suppose that it is possible to be so far off course that the correction would not be effective. It is likely based on proper navigation at the start of the flight as compared to a massive error. Using an extreme example, one could go 180 degrees in the wrong direction because their protractor was upside down and inoperative/missing navigation equipment, or just very poor skills and never have a chance of this method saving the day. This method is for the pilot that has used reasonable pilotage navigation skills but circumstances such as unforecasted winds have caused a significant error.
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SpeedhawkAirforce1
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Re: How do you guarantee finding that airport

Post by SpeedhawkAirforce1 »

Hahahaha. To the people saying the pilot should have carried spare batteries or downloaded an app to their phone, you are either joking and it's funny or you are missing the point. The intentional error or whatever you want to call it is most likely the best answer in this scenario. It's an orienteering trick that is older than aviation. You do the same thing when you go hiking in the backcountry. You're coming back from the summit and are taking a bearing out to the road where you parked your car. No matter how good you stick to your bearing and how good your calculations are in the real world you will not have pinpoint accuracy and will not know which way to turn to find your car once you hit the road, or in the OP's example the airport. Hence: intentional error. I have also used this to canoe accross big lakes with a portage on the other side while my friends took 1.5 hours of going back and forth on the opposite shore because they didn't know where the portage was in relation to where they made landfall. Now that I write that, I think this is most likely a very old nautical technique.
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