The short answer is there is no way to know with any great precision. If an official after-action report of the flight was written it has not survived, nor have any written reports of the other search flights. Colorado’s Commanding Officer Captain Wilhelm Friedell wrote an official report (The Friedell Report) of the ship’s search of the Phoenix Group, but it includes no flight times. Colorado’s Senior Aviator Lt. John Lambrecht wrote an article about the search flights for the Bureau of Aeronautics Weekly Newsletter (Lambrecht’s Report). His account includes many important details but not the length of time spent over each location searched. The best we can do is to constrain the possibilities using the available data. If we can determine the cruising speed of the aircraft, the total elapsed time from launch to recovery, and the minimum distance flown, we should be able to calculate the amount of time that could be divided among the three target areas.

USS Colorado (BB45) was a Maryland Class “super-dreadnought” launched in 1921. In 1937 she carried three Vought O3U-3 “Corsair” aircraft in floatplane configuration carried on three catapult rails – two on the after deck and one on top of the No. 3 Gun Turret. U.S. Navy photo

The Aircraft

Colorado’s aircraft were assigned to Observation Squadron Four (VO-4) which also had aircraft aboard BB45’s two sister ships USS Maryland (BB-44) and USS West Virginia (BB-46). The three aircraft aboard Colorado during the Earhart search were Bureau Numbers 9167, 9197 and 9288. Their squadron numbers were 4-O-4, 4-O-5, and 4-O-6.

The O3U-3 was an open cockpit, tandem two-place biplane. Specifications for the land plane version call for a top speed of 145 kts (167 mph) and a maximum range of  591 nautical miles (680 statute miles).

The Corsair was most commonly deployed in floatplane configuration, carried aboard cruisers and battleships for reconnaissance and to adjust fire for the ships’ big guns. We have been unable to find published performance numbers for the seaplane version but it was aerodynamically much “dirtier” than the land plane and undoubtedly more limited in speed and range.    The best indication of the speed actually flown during the July 9 mission comes from Lt. Lambrecht himself who later recalled that “we normally cruised at 90 knots indicated airspeed.”[1] The aircraft aboard the aircraft carrier USS Lexington (CV-2) also flew at 90 knots during the Earhart search.[2]

Mission Time

Excerpt from the Remarks section of the deck log of USS Colorado for July 9, 1937. Click image to open a large, readable version in a new window.

The mission on the morning of July 9, 1937 was to make an aerial inspection of three locations: McKean Island, Gardner Island, and Carondelet Reef. The battleship’s deck log records that plane 4-O-4 flown by the flight leader, Lt. Lambrecht, was the first to be launched at 0656. Thirty seconds later Lt. Fox was catapulted in plane 4-O-6. The third aircraft, plane 4-O-5 flown by Lt. Short, left the deck at 0700. We can therefore safely put the mission start time as not earlier than 0700.

The time for the conclusion of the mission can be put at 1020 when the ship changed course to begin recovering the returning aircraft. A good estimate of the total elapsed time for the mission, from 0700 to 1020, is therefore 3 hours and 20 minutes.

Mission Distance

Capt. Friedel’s official report states that the ship was at 3° 54′ South, 174° 46′ West when the aircraft were launched and at 4° 30′ South, 174° 24′ West for the recovery. Those positions are not logged in the ship’s deck log but they more or less agree with a reconstruction of the ship’s movements based on the log. The total distance from the launch point to each of the target areas and back to the ship at the recovery point – without regard for any searching or circling – is 243 nautical miles. The ship’s log records that during the flight the wind was constant from the east at 12 knots. Because the flight was essentially a round trip, the total elapsed time would not be significantly affected.

Excerpt from the deck log of USS Colorado for July 9, 1937. Click image to open a large, readable version in a new window.

The July 9 flight. Click image to open a large, readable version in a new window.

At 90 knots it should take the flight 2 hours 42 minutes to cover the basic distance flown, leaving 38 minutes of loiter/search time to be divided between the three target areas. Lambrecht’s article for the Bureau of Aeronautics Weekly Newsletter suggests that relatively little time was spent at McKean Island and Carondelet Reef. If we allot 5 minutes of searching to each of those locations we’re left with 28 minutes as a reasonable guess for the amount of time that was spent over Gardner Island. If we allow 10 minutes each for McKean and Carondelet that leaves 18 minutes for Gardner. A circuit around the perimeter of the island is roughly 10 nautical miles so, at 90 knots, it should take 11 minutes to make one trip around. The rest of the available time could be spent on more detailed inspections of anything of interest such as the lagoon, the shipwreck and the reported “signs of recent habitation.”

1.  Undated letter from Capt. John Lambrecht USN (ret) to Fred Goerner.

2.  “Based on the available information it was decided that the most effective altitude of the search was 300 – 500 feet and the most effective airplane speed was 90 knots.  This was confirmed by experience during the search.” – Capt. Leigh Noyes USN, “Report of Earhart Search.”