Western Front
Battle of the Somme: Captain Oswald Boelcke (40 victories), first great air combat tactician killed, aged 25, in Albatros mid-air collision over Pozieres with Jasta 2 wingman Lieutenant Erwin during a dogfight in which 8 German fighters down 3 RFC artillery observation aircraft and a Nieuport. One of 12 German aircraft losses in October. Boelcke was the man responsible for codifying the first well-known iteration of rules for aerial combat, the “Dicta Boelcke”:
https://en.wikipedia.org/wiki/Dicta_Boelcke
Eastern Front
Romania: Romanians successful actions in north Transylvania Passes.
In Jiu Valley, the Germans/Bulgarians retire leaving 2,000 prisoners.
Southern Front
Macedonia: Bulgarian attack in force on Ormali (Struma front), repulsed with heavy losses.
Asiatic and Egyptian Theaters
Fighting near Hamadan (Persia), Russians capture two villages.
Naval and Overseas Operations
(Night of 27/28 October): 23 German torpedo boats raid the Dover Strait. They sink 1 destroyer, 6 naval drifters, and 1 troopship.
Donaldson liner
Marina sunk by submarine without warning (18 lost, including six Americans) off Fastnet.
British hospital ship
Galeka totally wrecked by mine off Havre:
http://imgur.com/nfp8Xrp
U-boat sinks US
SS Lanao off Portugal.
Political, etc.
Germany: Count von Roedern, German Secretary for the Treasury, estimates the war has cost $62 billion for all the belligerent countries.
Anglo-German Agreement to exchange interned civilians over 45 years of age.
United Kingdom: British news film “Tropical Budget” showing Serbian operations in Macedonia, among other news:
http://film.iwmcollections.org.uk/record/index/5400
Austria-Hungary: Dr. Ernest von Körber appointed Austrian Premier (see 21st and December 14th).
Turkey: Halil Bey, Ottoman Foreign Minister, states, “We stand or fall with the Central Powers…The Germans cannot be beaten in this war.
Australia: Australia holds a plebiscite on whether or not to impose conscription. “No” wins with 51.61% of the vote.
United States: Contributions to the Democratic campaign for the upcoming election pass $1 million ($22 million today).
Greece: Venizelos' Provisional Government installed at Salonika.