The Action of 4 May 1917 was a naval and air engagement of World War I in the North Sea. The action took place between the German Zeppelin LZ92 (tactical name: L.43) and the Australian light cruiser, HMAS Sydney.
Sydney was serving in British waters when on 4 May 1917, while part of a patrol from Rosyth, Scotland, the ship took part in a battle with a German zeppelin, L.43. Commander John Dumaresq attempted to trap the aircraft by dispersing the rest of the allied warships in a circular formation with the zeppelin in the center, leaving Sydney alone to engage the enemy target. The airship dropped ten or twelve bombs in Sydney's direction, which failed to hit the ship, or any of the other Allied vessels. Sydney returned fire with her anti-aircraft guns. The engagement ended when both sides exhausted their ammunition. The zeppelin was forced to remain high to stay out of range of the flak, this meant that the bombs were dropped from too great of height to strike the allied patrol. There was no damage or casualties.