Drift in the Dark
This post is revised and the contents are now in a Google DOCS file via this link.https://docs.google.com/document/d/1arquMxBkJa-IBxmJYP1vgvWuETapBS1s5eM-HPKyilk/edit?usp=sharing (https://docs.google.com/document/d/1arquMxBkJa-IBxmJYP1vgvWuETapBS1s5eM-HPKyilk/edit?usp=sharing)
The purpose of the report is to show how Earhart and Noonan went missing on their flight from Lae to Howland Island. The core idea is that they were given an incorrect wind forecast. The evidence for this is in the weather reports from Nauru and Howland which show surface pressure reducing from West to East, which indicates a South Easterly wind and not a North Easterly as forecast. The effect of the incorrect wind forecast was a two degree left heading error. The actual wind then caused an additional 4 degree left drift and that 6 degree track deviation over the whole route was sufficient to put them fatally off-course. Their course is deduced from analysis of the radio messages which indicate what happened as they approached their ETA for Howland and commenced a search for the island.
The Chart
https://photos.app.goo.gl/bQGFARk9yqf12BfdA (https://photos.app.goo.gl/bQGFARk9yqf12BfdA)
The Flight Plan
https://photos.app.goo.gl/N1paneYtkjWjS76t7 (https://photos.app.goo.gl/N1paneYtkjWjS76t7)
Quote from: Colin Taylor on March 19, 2023, 07:12:10 AM
The whole world-flight enterprise was ill-conceived and badly executed but I think that the most likely final cause of the disaster was an undetected incorrect wind forecast.
Agreed. The wind forecast Noonan had proved to be inaccurate. Wind forecasts usually are.
Quote from: Colin Taylor on March 19, 2023, 07:12:10 AM
I can show you evidence in the official records which verify this.
The Itasca radio log and Jim Carey's diary verify that Earhart reported an overcast at 14:15 GMT. Without celestial fixes, Noonan could use only dead reckoning to estimate their position based on the last available wind information and his best guess about how it might change.
Quote from: Colin Taylor on March 19, 2023, 07:12:10 AM
The effect of the incorrect wind forecast was to cause Noonan to calculate a heading which would give a two degree left heading error. The actual wind then caused an additional 4 degree left error and that 6 degree track deviation over the whole route was sufficient to put them fatally off-course.... I will attach thumbnails of the images and links to the full-size images.
I'm aware of no winds aloft reports for where the flight was at that time.
(Your links to the full size images don't work.)
On July 3, 1937, Rear Admiral Orin Murfin convened a conference of senior naval officers at Pearl Harbor to decide where
USS Colorado should search for the plane. They decided that the available information "seemed to indicate that the most probable reason for missing Howland Island would be that of stronger winds than normally expected in the region, and that the plane had probably been carried southeast of Howland, a greater distance than that from which Howland could be sighted."
Your speculation apparently differs from theirs.
In addition, none of Earhart's radio reports of her position were likely accurate at the time of her transmission. Based upon her transit to Hawaii earlier in the world flight, it is clear that the broadcast positions were those previously taken before the time of transmission, sometimes up to 45 minutes earlier.
Somewhere in the TIGHAR archives is a report that I did documenting a Monte Carlo simulation of AE's flight, which contained two sets of tracks. First, I had to assume the entire fight navigation was done by dead reckoning. Secondly, the first flight path consisted of a DR course based upon what weather information she had before she left Lae, and assuming they corrected for cross-drift. The second flight path was based upon the actual weather reported after she left Lae, assuming the same corrections as the first path. With constraints of seeing a ship ahead near Nauru, a reported crossing over one of the intervening islands, and AE's radio broadcasts, when AE thinks she's close to Howland, the MC simulation shows she's substantially to the SW of Howland.
OK I have changed the links. They should work now
The significant thing about the winds is that sailors had been reporting SE Trades for centuries.
The significant thing about the radio reports is not the exact timing but the order in which they were sent.
As I will explain.
/
Quote from: Randy Jacobson on March 19, 2023, 08:36:10 AM
In addition, none of Earhart's radio reports of her position were likely accurate at the time of her transmission. Based upon her transit to Hawaii earlier in the world flight, it is clear that the broadcast positions were those previously taken before the time of transmission, sometimes up to 45 minutes earlier....
With constraints of seeing a ship ahead near Nauru, a reported crossing over one of the intervening islands, and AE's radio broadcasts, when AE thinks she's close to Howland, the MC simulation shows she's substantially to the SW of Howland.
Randy - I sent you another PM perhaps a month or two ago. I know no one checks these very frequently anymore, but please take a look when u have time and give me you thoughts. Thanks
Diego.
Quote from: Ric Gillespie on March 19, 2023, 08:17:16 AMI'm aware of no winds aloft reports for where the flight was at that time.
I searched through the TIGHAR archives and found upper-air wind reports (presumably from observations of weather balloons). Itasca reported on the 30th June, Easterly 11-19kts at 8000ft. On the 1st July, Easterly 23kts at 3000ft and Easterly 22kts at 5650ft. Nauru reported on 1st July, Easterly 14kts at 2000ft, Easterly 12kts at 4000ft and Easterly 24kts at 7500ft.
There are three forecasts issued by the US Navy at Pearl Harbour.
30th June, 09:15, Lae to Ontario: ESE 10-15: Ontario to 175E:E 10,
175E to Howland: ESE 15-20 30th June, 22:50, Lae to Ontario: ESE 12-15, Ontario to 175E: ENE 18;
175E to Howland: ENE 15 1st July, 19:05, Lae To Ontario: ESE 25,
Ontario to Howland: ENE 20Why was the forecast for the middle and final thirds of the track changed from ESE to ENE? Looking at the date/time stamps, these forecasts were probably issued by different individual officers with different opinions.
The flight was originally planned for the spring when the Sun was overhead the Equator, and the Inter-Tropical Convergence Zone was on the Equator. The track of 078 degrees True crossed the Equator, so that the first third of the track was South of the Equator and, in the spring, the wind could be ESE while the last third of the flight would be North of the Equator and the wind could be ENE. However, the flight was delayed to the Northern Summer by which time the Sun was over the Tropic of Cancer at 23 degrees North and the ITCZ had moved North, drawing the South Easterly Trade wind North of the Equator. The whole route should then be subject to an ESE wind. Did the forecasters miss this important detail?
The comment by Rear Admiral Murfin reveals the depth of understanding of the weather. If, as he says, the wind had been stronger [from the ENE], that would put the Electra West Southwest of Howland not Southeast of Howland. But Murfin was a Navy man, a fighting man. Clearly, he thought Earhart was defeated by a STRONGER wind, not tricked by different wind direction.
In fact, if Earhart was off track to the South, with Baker Island being Southeast of Howland, to miss both Islands she would need to be even further off track, at least eight degrees South of track instead of six degrees North. That would require an even stronger Northeasterly wind which would be even less likely than the forecast East Northeast wind and considerably less likely than an East Southeasterly trade wind.
So, I don't have to speculate about much, all the evidence is right there. The winds were Easterly which would give the flight Left drift, amplifying the left track error caused by the incorrect forecast.
Out of three forecasters and one Admiral, one of them got it right.