26 Jan 1942
The periscope on U-404 was damaged during an air attack in the North Atlantic.

28 Jul 1943
The sinking of U-404 At 11.07 hours, the boat was located after a radar contact by an American B-24 Liberator aircraft (4th A/S Sqdn USAAF/Y, pilot Maj Stephen McElroy) but the attack failed because the depth charges failed to release. The aircraft waited for the boat to resurface and attacked again at 15.17 hours. Despite of an 20mm shell detonating inside the cockpit without hurting anyone, the pilot dropped eight depth charges into the swirl of the diving boat. AA damage to the radio and one of the engines forced the Liberator to return to base.Another American Liberator (4th A/S Sqdn USAAF/H, pilot 1Lt Arthur J. Hammer) attacked U-404 twice after resurfacing at 17.45 hours. Again the Liberator had to left due to AA hits in one of the engines, the tail and the fuselage. The last attack was seen by a third aircraft, the British Liberator BZ781 (224 Sqdn RAF/W, pilot F/O R.V. Sweeny), which eventually attacked and sank the boat. The third Liberator had also been hit by AA fire in one of the engines during the attack run and barely made it back to base after jettison all guns and other loose equipment. (Sources: Franks/Zimmerman)

2 recorded attacks on this boat.