Print

[Colin Taylor]

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
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
 

 The Flight Plan
https://photos.app.goo.gl/N1paneYtkjWjS76t7

[Ric Gillespie]

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.

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.

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.

[Randy Jacobson]

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.

[Colin Taylor]

OK I have changed the links. They should work now

[Colin Taylor]

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.

[Diego Vásquez]

/

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.