Sgt T. Koc was born on 9th August, 1913.
In May 1934, Tadeusz joined the Aviation Reserve.
He was promoted to Lieutenant on 15th October 1937.
After completing training on 12th October 1940, he was sent to 303 squadron.
On 8th November, he was transferred to 245 squadron.

On 22nd February 1941, Tadeusz was posted to 317 Squadron.
On 11th November, while the Squadron was part of a Wing carrying out an Offensive Sweep over Lille, Tadeusz saw a spitfire chasing an ME 109 and being itself chased by two ME 109F’s. He turned on the last one and gave it a short burst followed by a longer burst after which the enemy aircraft went down out of control pouring out black smoke.

On 15th March 1942, Tadeusz took part in escorting bombers over France. While in the air, dense fog formed over most of the south-east, and with zero visibility returning home, eight aircraft were lost with one pilot killed and several injured.
On 28th April, while on a sweep over France, (Flying Officer) Tadeusz shot down a FW190. He followed this the following day when, escorting Bostons for an attack on Dunkirk, he shot down a FW 190 and pusued another. The second enemy pilot dived immediately when attacked, but Tadeusz followed him down, firing short bursts. He only left him when the enemy aircraft appeared to be out of control.
On 4th July, the squadron took off at 19.24hrs for the operational flight 'Circus 186', and set course for Colchester flying at 500 ft. On to Gravelines they were required to reach 26,000 ft. at 20.09 hours. When this ceiling was reached, Tadeusz's engine stopped (as did F/O Solak's & Kumeiga's), and had to drop to 500 ft before the engines restarted. They landed back at 20.55 hrs at home base without making combat.