The World Flight, First Attempt:

Oakland to Honolulu

It is instructive to investigate the various procedures for radio, navigation, and piloting for the best documented segment of Earhart’s World Flight: the crossing the Eastern Pacific from Oakland to Honolulu on March 17, 1937. This first attempt at the around the world flight provides many clues and insights into later flight segments. Much careful planning by William Miller, on “loan” from the Bureau of Air Commerce, well documented and distributed to the US Navy and US Coast Guard, was carried over to the second attempt. Unfortunately, Bill Miller was assigned to investigate the potential for air mail routes to New Zealand shortly after Earhart’s abortive crash take-off in Honolulu, and was unavailable to provide the detailed planning necessary for a successful second attempt for the world flight. George Putnam took over the logistics and planning, but appeared not to be as well versed in this art as Miller.

Preparations

Upon arrival in Oakland on March 10, 1937 from Burbank, Earhart ran into a week of bad weather, preventing her planned take-off on the 15th.1 Miller was coordinating the scheduling of the USCG vessel Shoshone to leave Honolulu for Howland, the USS Whippoorwill for the Howland/Honolulu half-way point, and the USS Ontario to leave Pago Pago, American Samoa for their respective stations. At the same time, reports from Howland Island were not terribly encouraging regarding the final preparation of the runways, as the workmen needed tractor spares that the Shoshone was to bring.

On top of all this, a Bureau of Air Commerce official, Mr. Reining, sent a telegram to Earhart, with a copy to Miller saying that she should contact Mr. Marriott or Mr. Bedinger, the supervisory aeronautical inspector, for nonscheduled instrument rating or flight check ability to fly entirely by instruments, as her flight permits would not be released – Earhart’s pilot’s license was about to expire, and she needed to take her biennial flight review prior to take-off from Oakland.2 The next day, Bedinger gave Earhart the instrument flight check, but the written and radio tests “...not given account her desire to expedite and save engines.”3 This is most curious, as the engines were relatively new and would not need servicing for quite some hours, and a simple one hour test to verify her radio skills would not significantly contribute to engine wear. Nor was Earhart in a big hurry, as there were still four more days planned prior to take-off. The desire to avoid the radio test was probably the first contributing factor to Earhart’s failure to reach Howland in July. Regardless, the BAC in Washington DC put her permit in an airmail package to Oakland.

On March 12, Miller sent out telegrams to all the major parties announcing that Earhart was scheduled to leave Oakland on the 15th, weather permitting, and would have Fred Noonan, Capt. Manning, and Paul Mantz aboard the plane. Mantz was scheduled to leave the plane in Honolulu; Noonan at Howland Island, and Manning in Darwin, Australia.

On March 13, due to the heavy rains, Earhart asked through the Bureau of Air Commerce whether she could use the San Francisco airport with its 3000 foot runway. The problem would be that the prevailing wind direction would necessitate a take-off towards obstruction – not normally hazardous, but it might be for Earhart’s overloaded plane.4 The BAC responded the next day that it was up to local authorities alone to make that decision.5 Apparently, the weather was so bad on the 15th that the take-off was delayed another day. Earhart requested that the Navy loan her team an octant for the transpacific flight from San Diego and that it be air shipped to Oakland; LCDR George Manning, USNR, would sign for the octant.6 Approval was provided, and the octant shipped on the 16th, arriving approximately 2:50 PM.7 Her scheduled departure was deferred until the 17th, due to the weather, which was improving somewhat.

Radio Procedures

It was common knowledge among the parties involved that Earhart had 6210, 3105, and 500 kHz aboard her plane. It wasn’t until March 3rd, however, that a request was made to determine whether the two ships in the half-way points could use those frequencies for communication.8 The USCG Shoshone, scheduled to visit Baker, Jarvis, and Howland Island, departed that same day from San Francisco to Honolulu, and the CG representatives there knew what radio capabilities that ship had. The following day, notification was provided that the USS Whippoorwill, scheduled to be half-way between Honolulu and Howland, could not operate voice above 3000 kHz.9 However, the Fleet Air Base, Pearl Harbor, stated that it could install equipment for the 3105 kHz series using gas-powered generator.10 Later that day, information from American Samoa Naval Facility at Tutuila stated that the Ontario could not operate voice above 1000 kHz.11 On March 8th, Miller sent a telegram to Putnam stating that the Shoshone could operate on all frequencies Earhart intended to operate, but that the two Navy vessels could only receive on all frequencies.12 On March 9th, the Hawaiian Sector of the CG asked the San Francisco Division to ask Miller what frequencies the Shoshone should transmit voice and if 3105 and 6210 kHz were still to be used by the crew of the plane.13 (Note that 500 kHz is not mentioned as a primary frequency at this time.)

On March 10th, the Shoshone left Honolulu without information regarding what radio frequencies to use with Earhart or what her modus operandi would be, a situation eerily similar to the June/July trip of the Itasca. The USS Ontario also left Pago Pago for her station half-way between Howland and New Guinea, and without specific radio instructions to communicate with Earhart. The Ontario was scheduled to arrive on station on March 18th. Finally, on March 11th, Richard Black aboard the Shoshone asked the USCG representatives at San Francisco to clarify the radio plans for the Pacific legs of the flight, including frequencies covered by plane's direction finder, transmitting frequencies, type of emission and whether Earhart could use Morse code.14

On March 12th, the USS Quail was directed to take the place of the Whippoorwill, for unknown reasons.15 Late that same day, Earhart requested through the USCG office in San Francisco that the USCG vessel Taney be detailed to a position 200 miles northeast of Honolulu and act as a radio beacon for her flight to Honolulu,16 which action was approved the next day.17 Further, Earhart wanted the Makapuu radio beacon to be on full time. The Lighthouse superintendent stated that the beacon could be on for one minute, then off for two minutes, but that full, continuous broadcasting had to be approved by the Lighthouse Commissioner.18 Approval for operation in fog conditions was provided on the 13th.19 On March 13th, definitive information regarding radio procedures was issued by Earhart, and forwarded by the USCG, San Francisco Division, and sent to the Shoshone and Hawaiian Sector of the USCG. This radio message stated that

... one should call the plane from one to six minutes past the hour, and 31 to 36 minutes past the hour. The first two minutes use 3105 kHz; the second two minutes 6210 kHz, the third two minutes use 500 kHz until contact is made. If no contact after three hours, the Shoshone should transmit long dashes on 375 kHz, followed by the its call letters. The plane will attempt to take bearings. Keep this up every ten minutes, starting on the even hour, lasting for four minutes. The plane will contact you after your transmission, following the same procedure of ship to plane. All times are to be GCT; plane call sign is KHAQQ, show searchlight as plane approaches Howland during darkness and make smoke during daylight hours.20
For the flight from Oakland, USCG San Francisco advised that it would
... monitor the whole flight, and that Earhart will attempt to communicate at 31 to 36 minutes past the hour for the first seven hours: 2 minutes at 3105 kHz, 2 minutes at 6210 kHz, and 2 minutes at 500 kHz. For Honolulu stations, the same procedures will be followed, but at 41 to 46 minutes past the hour. Calls will be made when necessity demands it, and all times are GMT. PAA will handle all traffic and direction finder bearings, answering the plane on 2986 kHz using Morse code.21
Further information is provided to major Navy assets stating that
... Earhart call sign KHAQQ, will transmit on 500, 3105, and 6210 kHz using CW telegraphy and voice. Plane has a direction finder covering 200 to 1430 kHz will all wave receiver for telegraphy. A suggestion was made to have a direction finder set up on Howland if practicable. No amateur contacts will be made, and all transmissions will be on the frequencies stated.22
As an aside, the Chief of Naval Operations, Office 20 (Director of Naval Communications), asked that the US Navy track the plane by available high frequency directional finders for comparative tests between Navy and PAA equipment.23 After Earhart landed on Honolulu on the 18th, Richard Black sent a radio message saying that a portable radiophone is available on Howland on 2670 kHz, and can answer any questions regarding the runways as she passes over.24
The Flight to Honolulu and Navigation

We are indeed fortunate that the navigational charts used by Noonan and Manning still exist and are available at the Purdue University Library. The base charts were developed by Pan American Airlines, and are so marked. Apparently, Fred Noonan still had access to PAA materials at this time. TIGHAR researchers have examined these charts, and have determined the meaning of all markings on them. By reconstructing the flight, based upon these notes, together with the radio messages transmitted in flight, some interesting clues come out regarding how Earhart and Noonan operated together.

Earhart left Oakland on March 17, at 4:32PM PST (0032/18 GMT) into a 14 mph wind using 1897 feet of takeoff on a muddy field in 25 seconds.25 She was already in trouble, however, with the government bureaucrats: she left without mosquito inspection and disinfectant.26 The following radio transmissions were received during her flight:

0842 GMT "KHAQQ position intercepted at 0842 GMT 31°N, 139°49°W, All's well." Reported by USCG Hawaii at 0850 GMT.27
1058 GMT "At 0028, KHAQQ on phone, reports all's well, no position." Reported by USCG Hawaii at 1105 GMT.28
1100 GMT "Intercepted position at 1100 GMT 29°15'N, 147°38'W." Reported by USCG Hawaii at 1125 GMT.29
1200 GMT "Intercepted position at 1200 GMT: 27°42'N, 149°40'W". Reported by USCG Hawaii at 1245 GMT.30
~1300 GMT "Following intercepted from plane: speed approximately 155 land mph, approximate time of arrival 0800 PST". Reported by USCG Hawaii at 1305 GMT.31
1410 GMT "Intercepted position at 1410 GMT: 25°N, 143°W." Later corrected to 153°W. Reported by USCG Hawaii at 1455 GMT.32
1545 GMT "Following intercepted at 0515 quote Will arrive 1620 GMT". Reported by USCG Hawaii at 1555 GMT.33
1615 GMT "Earhart plane off Diamond Head at 0545 Honolulu time." Reported by USCG Hawaii at 1617 GMT.34
1630 GMT "Earhart plane arrive Honolulu at 0600". Reported by USCG Hawaii at 1632 GMT.35

Apparently, Bill Miller was on the phone to officials at Wheeler Field, as he immediately sent out telegrams that Earhart arrived at 1625 GMT.36

The following are descriptions of the various markings on the two charts for the Oakland-Honolulu flight, in chronological order. All times on the charts are noted in GMT time.

0128 GMT 37°18'N, 123°25'W. This is a point along the rhumb line connecting San Francisco to Honolulu.
0130 GMT 37°15'N, 123°22'W. Unknown determination of how position obtained, but obviously not a DR.
0139 GMT 37°6'N, 123°31'W. Probably a DR point.
0200, 0230, 0300 GMT Projected points along a line extending from Pt. Montara Radio Beacon, spaced 60 nm apart, suggesting a 20 knot headwind expected. This procedure of marking future, expected positions along a course line was typical of Noonan's charting.
0204 GMT A radio bearing taken upon a station (unnamed) outside of SF harbor.
0313 GMT A LOP taken against Venus
0317 GMT A radio bearing taken against Radio Bonita, and a LOP taken against Sirius. When combined with the Venus shot, a position fix of 35°5'N, 127°57'W for 0317 GMT.
0330, 0400, 0430 GMT Projected DR points along a corrected baseline, passing through the 0317 GMT fix and 0128 GMT fix, based upon 155 knots true over the ground.
0432 GMT A LOP taken against Alphecca. This is the only error on the chart, as Alphecca is well below the horizon at this time and location, despite it being in the proper look angle.
0442 GMT A LOP taken against Sirius.
0446 GMT A LOP taken against Polaris. Combined with the Sirius 0442 GMT LOP, a position fix at 33°20'N, 131°50'W results.
0500, 0530, 0600, 0630 GMT A new set of projected DR points, based upon 150 knots true over the ground.
0600 GMT Position of commercial vessel President Harrison, at 34°4'N, 137°12'W.
0613 GMT A LOP taken against Denebola.
0734 GMT A LOP taken against Spica.
0738 GMT A LOP taken against Sirius, which, when combined with the 0734 GMT LOP, provides a position fix at 0738 GMT of 31°25'N, 138°53'W.
0800 GMT A new projected DR position. At this time, the charts were changed, reflecting the need to use a more westerly chart that includes the Hawaiian Islands.
0800,0830, 0900 GMT Projected DR positions, based upon plane course and 0738 GMT fix, assuming 124 knots true over the ground.
0900 GMT Plane makes course correction to a more southerly direction to account for the northerly wind set.
0907 GMT A LOP taken against Capella.
0930, 1000 GMT Adjusted projected DR positions, using new base course.
1003 GMT A LOP taken against Polaris.
1007 GMT A LOP taken against Capella, which, when combined with the 1003 GMT LOP, provides a position fix of 30°4'N, 145°30'W. A new set of projected DR positions are plotted with this fix for 1000 and 1030 GMT.
1045 GMT A major course correction is made to a more southerly direction, as the set due to winds is still northerly.
1100, 1130, 1200 GMT A new set of projected DR positions are plotted in advance.
1115 GMT A radio bearing is taken or provided against the PAA Makapuu radio station.
1218 GMT Another radio bearing is denoted against Makapuu.
1300 GMT Another plane course correction, again to a more southerly direction.
1323 GMT A LOP against Antares.
1328 GMT A LOP against Vega.
1337 GMT A radio bearing taken/provided from Makapuu.
1339 GMT A LOP against Polaris. When combined with the 1337 radio bearing, a fix of 25°54'N, 153°26'N results.
1410 GMT Another plane course correction to a more southerly direction.
1450 GMT A radio bearing taken/provided from Makapuu.
1520 GMT A LOP taken against Vega, which, when combined with the 1450 radio bearing, provides a navigational fix of 22°40'N, 156°37'W.
1540 GMT A radio bearing taken/provided from Makapuu. This is the last mark on the chart.

In summary, Noonan made use of seven radio bearings, 14 star/planet LOPs (of which nine were used for navigational fixes), and the plane made only four course corrections. Analysis of the flight path versus weather maps produced after this date show major concurrence with the winds aloft patterns.37 It is clear that the navigator’s major responsibility was to monitor the progress of the flight, and to suggest course corrections only when deviations from desired flight path became too extreme. Use of projected, future DR positions allowed Noonan to check his forecasts vs. later navigational fixes to update his speed and direction over the ground, and to offer approximate positions, when necessary.

A comparison between the radio broadcast positions and the actual navigational fixes reveals some interesting clues. First, there is no information from radio messages regarding the first half of the trip.

  • At 0842 GMT, a position of 31°N, 139°49′W was provided. This position corresponds to the 0800 GMT DR position, extrapolated from 0738 GMT fix, and was actually 31°10′N, 139°49′W. Thus, this position is 42 minutes old when broadcast.
  • At 1058 GMT, Earhart broadcasts that all is well, but no position is provided. Note that this is an unscheduled radio broadcast.
  • At 1125 GMT, USCG Hawaii broadcasts: “Intercepted position at 1100 GMT 29°15′N, 147°38′W.” This can be interpreted to mean that the interception occurred at 1100 GMT, but the possibility is that the 1100 GMT position is provided, which, in fact, is the case. This is the DR projected position, based upon the 10007 GMT fix, and having the plane make a course correction at 1045 GMT. Since Earhart’s radio schedule broadcast is set for 41 to 46 minutes after the hour, but the actual transmission is probably 11 to 16 minutes past the hour. Thus, this position for 1100 GMT is at least 11 minutes old.
  • At 1245 GMT, USCG Hawaii broadcasts that it intercepted Earhart stating that her 1200 GMT position is 27°42′N, 149°40′W. This is indeed the 1200 GMT DR projected position, with the last fix at 1007 GMT and a course correction between the two times. Note that this broadcast is consistent with Earhart’s original radio schedule. This position is well over 41 minutes old.
  • At 1455 GMT, USCG Hawaii broadcasts that they intercepted a position at 1410 GMT of 25°N, 153°W. The map indicates that at 1410 GMT, a course correction was made and that the DR position at that time was approximately 25°N, 154°30′W. This is the radio message that was corrected, and the radio operator listening apparently misconstrued the longitude information. The previous navigational fix prior to this DR was at 1339 GMT. If Earhart stayed on her radio broadcast, she was providing a position well over 30 minutes old at 1441 GMT.

In all cases, Earhart provided dead reckoning positions. Of the four documented positions, three were provided with times, but the wording provided by the USCG Hawaiian Sector leads to some ambiguity as to when Earhart stated these positions. Interestingly, all four messages indicate that the positions provided were well prior to the actual broadcast times: 42, 11, 41, and 30 minutes. Based upon this analysis, one can easily speculate that Noonan's method was to project future positions via dead reckoning, and provide that information to the pilot sometime prior to the radio broadcasts. In no instance does Earhart provide timely information, nor does she provide an actual navigational/celestial fix and time of the fix to help constrain exactly where the plane was.

Interestingly, Earhart reasonably stayed on radio schedule, but also chose to use the half-hour schedule when broadcasting during the second half of her flight. This procedure was not expected, according to the radio schedule promulgated by the USCG San Francisco Division described above.

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