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Author Topic: Lae to Howland to Niku Planning and Simulation  (Read 1039 times)

Christian Stock

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Lae to Howland to Niku Planning and Simulation
« on: March 31, 2020, 11:40:06 AM »

We are on lockdown now, so I have been trying to recreate Amelia Earhart’s last flight in X-plane, which is a very good flight simulator. I’ve done “chunks “ of the flight so far, but never the entire thing in a small plane at 130 Knots. Here is my experience so far:

First, I downloaded a Lockheed Electra 10E from an X-plane user site. It was quite good, but it had more modern avionics than the original, and even the X-Plane facsimile of a Garmin GPS. X-plane comes with a variety of stock aircraft, so I was able to look at different aircraft, and even change fuel consumption rates to match the endurance of NR16020. Ultimately, I decided to fly with X-plane’s Columbia 400, which was nice since I once helped build a Lancair. The X-plane Coumbia 400 is equipped with the X1000, a really good facsimile of the Garmin G1000. I chose this because it was easier for me to simply set an airspeed, altitude and heading, then walk away from the computer for hours at a time.

Using the X-Plane scenery designer, I created an airfield at Howland Island. It gave me options for grass, gravel, or pavement, and I went with a regular concrete runway. I also added a rotating beacon and a helipad, but otherwise kept it simple. For grins, I also stuck a gravel runway on Nikumaroro, at approximately the location of the coral reef.

Since I don’t have sectionals from that area, I used a well-known flight planning site to plot a course. I assumed she would not have attempted to fly over the mountains to the northeast of the field, so I planned to fly southeast to Lae, overfly the city, and then set up on my course. I found that the course overflies a very distinctive peninsula on Bougainville (now an airport there), so that would have been a good first check of the wind speed and direction. This site was kind enough to provide magnetic headings, which will be important since the magnetic variance will swing from 5 degrees at the Lae airport to 10 degrees at Howland.

I can add weather as-needed, such as layers of wind, precipitation, or clouds. As in real life, if there is ANY kind of cloud cover, Howland is really easy to miss. Nikumaroro is much easier to see. Howland is a dime in a jar of pennies. Niku is a quarter.

Regarding the flight to Niku on the 157/337 line, I can plan backwards from Niku and see that the 337 line passes about 45 to 50 miles east of Howland, so we know they went too far, which was probably just a function of looking for the island. It’s just a matter of where they picked up the line. Were they North of Howland and flew 3 hours to Niku, or were they South and flew 2 hours? I’ve included screen captures of these two scenarios. One thing that is evident is that, if they missed to the South and flew 2 hours, that means they never crossed the equator on the flight from Lae, and missed Howland by about 1 degree South. That seems like a big error. I think it is more likely that the landfall took them well North and East, and they flew 3 hours on the 157 line to Niku.
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Ric Gillespie

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Re: Lae to Howland to Niku Planning and Simulation
« Reply #1 on: March 31, 2020, 12:21:05 PM »

Regarding the flight to Niku on the 157/337 line, I can plan backwards from Niku and see that the 337 line passes about 45 to 50 miles east of Howland, so we know they went too far, which was probably just a function of looking for the island.

A 157° line through Howland passes about 10 nautical miles east of Niku.

It’s just a matter of where they picked up the line. Were they North of Howland and flew 3 hours to Niku, or were they South and flew 2 hours?

The evidence strongly suggests they hit the LOP about 180 nautical miles south of Howland.

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Christian Stock

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Re: Lae to Howland to Niku Planning and Simulation
« Reply #2 on: March 31, 2020, 02:17:13 PM »

So when she said they were flying a 157/337 line, was she referring to true or magnetic? I worked this all up initially with 337° true from Niku and it did indeed pass 10nm West of Howland.


A 157° line through Howland passes about 10 nautical miles east of Niku.

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Ric Gillespie

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Re: Lae to Howland to Niku Planning and Simulation
« Reply #3 on: March 31, 2020, 02:53:10 PM »

The 157/337 line is a Line of Position 90° to the rising sun which rose at 67° True in th Central Pacific on June 2, 1937.
To fly 157° True Earhart would have to convert that to magnetic using the variation current at that time.  Variation changes over time so if you're trying to recreate her flight you can't use 2020 numbers.
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Christian Stock

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Re: Lae to Howland to Niku Planning and Simulation
« Reply #4 on: April 02, 2020, 02:36:17 PM »

I have to do it with current numbers because the world is 2020 in the sim. I suppose I could find a day in 2018 to 2022 that roughly matches that day in 1937. Apparently, in the upcoming MS Flight Sim 2020, you can set a date and get accurate skies throughout the globe.

I did a Howland to Niku flight last night. I set a pretty stiff wind, with some gusts, and started from a point about 10-15nm West of Howland. I corrected for wind and magnetic and set the autopilot to fly 137° at 136kt and 1200ft, then set my iphone timer for 2.5 hours. When the alarm went off, I was about 20nm away, and the Western tip of Niku soon appeared. I ended up passing about 3 miles West of Niku before taking the controls, turning toward the island and snapping this screenshot.

Yeah, I know its nerdy, but no sports on TV.




The 157/337 line is a Line of Position 90° to the rising sun which rose at 67° True in th Central Pacific on June 2, 1937.
To fly 157° True Earhart would have to convert that to magnetic using the variation current at that time.  Variation changes over time so if you're trying to recreate her flight you can't use 2020 numbers.
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Christian Stock

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Re: Lae to Howland to Niku Planning and Simulation
« Reply #5 on: April 02, 2020, 03:16:11 PM »

Here's a weird one. I was checking to see which abbreviation of knots was correct, kt or kn, and searched kn on Google. It popped up with a ticker symbol for a company in Itasca, IL.
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Ric Gillespie

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Re: Lae to Howland to Niku Planning and Simulation
« Reply #6 on: April 02, 2020, 03:18:53 PM »

Yeah, weird.  I believe kts is correct.
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Christian Stock

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Re: Lae to Howland to Niku Planning and Simulation
« Reply #7 on: April 02, 2020, 03:24:39 PM »

Apparently all three are acceptable:

"The knot (pronounced not) is a unit of speed equal to one nautical mile (which is defined as 1.852 km) per hour, approximately 1.151 miles per hour (mph). The abbreviation kn is preferred by the International Hydrographic Organisation, which includes every major sea-faring nation; however, the abbreviations kt (singular) and kts (plural) are also widely used." - http://researchhubs.com/post/engineering/fundamentals/knot.html

Yeah, weird.  I believe kts is correct.
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