What led to the loss of the Edsall, Langley and Pecos et al

War Plan Orange, The Asiatic fleet was more of a short term deterrence to delay any attacker to allow time for the Pacific Fleet to Arrive on the scene. Initiated in 1919 with revisions through 1938  It failed to foresee the significance of the technological changes to naval warfare, including the submarine, air support and aircraft carriers.

Concept by RADM Rodgers  1911.

Japanese air attacks on airfields in the PI destroyed most of the Far East Air Force.  The Asiatic fleet was therefore without any kind of air cover and 

numerous ships were lost to attacks by Japanese aircraft most notably the "Prince of Wales and Repulse" the allies most powerful ships.   

Japan observed two events in the earlier part of the war in Europe.  One was the destruction of the Italian fleet by 21 British Fairy Swordfish biplanes carrying torpedoes at the Island of Taranto in November of 1940.   Hence the idea for Pearl harbor.

The second event the Japanese noted the evacuation of 350 thousand allied troops from Dunkerque and sought to prevent a similar evacuation from Java.

To that end they positioned two Naval battle groups south of Java to intercept allied warships and merchantmen heading to Fremantle.

Previous attempts to get aircraft to java did not succeed.  The Langley/Sea witch Mission to deliver Crated P-40 aircraft to Java was the last effort to provide the Asiatic fleet some air cover.  (The Edsall and Whipple had sustained damage in earlier actions and were chosen for the less dangerous mission to escort Langley to Java).  The Sea witch did deliver aircraft to java which  were subsequently destroyed to deny the enemy their use.  The pilots and ground crews remained on Edsall.

Edsall was ordered to Java to deliver the pilots and ground crews and then later to retreat to Fremantle Australia.  Whipple was ordered to the Coco's islands and Pecos to Fremantle. It is believed Edsall picked up distress calls from Pecos and headed to render assistance.  Edsall was intercepted by Kido Butai and earned her second battle star.  Whipple returned to the area of the Pecos sinking and located  the survivors and recovered about a third of them and due to a sonar contact cleared the area.

And then the Phoenix wandered back by....

Sea Witch was part of a five ship convoy headed for Colombo and escorted by the USS Phoenix.  Sea Witch and Langley left the convoy and separated and headed for Java. Sea Witch delivered 27 crated P-40 aircraft which were subsequently destroyed to deny them to the enemy. Langley met up with Edsall and Whipple but was damaged by air attacks  beyond repair and sunk by torpedoes from the Whipple taking the other 32 assembled p-40 aircraft with her.

The Phoenix as photographed above exits Pearl Harbor after the attack with no damage.  After Langley and Sea Witch left the convoy she was escorting to Colombo she was relieved of escort duty by a British Cruiser 

and then sailed right back through the area in which Pecos and Edsall were lost the same evening as the losses.  Whether she heard the distress signals

or other radio transmissions is not clear.  After arriving in Fremantle her crew was subject to hostile treatment by the Asiatic fleet survivors who had recently arrived on the Whipple over the fact that they, the Phoenix crew,  did not search for or pick up survivors of the sinking of the  Pecos.  It was reported that fights broke out between these crews in public establishments of Fremantle.

Pecos took aboard the crew of the Langley after she was abandoned from Whipple and Edsall at Christmas Island and proceeded to Fremantle Australia.  En route to Fremantle spotter aircraft from Kido Butai spotted her and soon dive bombers arrived.  The crew of the Langley found themselves in the sea again with new company in the crew of the Pecos.