Flight-Lieutenant Hornell was captain and first pilot of a twin engined amphibian aircraft engaged on an anti-submarine patrol in northern waters. The patrol had lasted for some hours when a fully surfaced U-boat was sighted, travelling at a high speed on the port beam. Flight-Lieutenant Hornell at once turned to the attack. The U-Boat altered course. The aircraft had been seen and there could be no surprise. The U-boat opened up with anti-aircraft fire, which became increasingly fierce and accurate.

At a range of 1,200 yards the front guns of the aircraft replied; then the starboard gun jammed, leaving only one gun effective. Hits were obtained on and around the conning tower of the U-boat, but the aircraft itself was hit, two large holes appeared in the starboard wing.

Ignoring the enemy’s fire, Flight-Lieutenant Hornell carefully manoeuvred for the attack. Oil was pouring from his starboard engine that was, by this time, on fire, as was the starboard wing; and the petrol tanks were in danger. Meanwhile, the aircraft was hit again and again by the U-boat’s guns. Holed in many places, it was vibrating violently and very difficult to control.

Nevertheless, the captain decided to press home the attack, knowing that every moment the chances of escape for him and his gallant crew would grow more slender. He brought his aircraft down very low and released his depth charges in a perfect straddle. The bows of the U-boat were lifted out of the water; it sank and the crew were seen in the sea.

Flight-Lieutenant Hornell contrived, by super human efforts at the controls, to gain a little height. The fire in the starboard wing had grown more intense and the vibration had increased. Then the burning engine fell off.

The plight of the aircraft and crew was now desperate. With the utmost coolness the captain took his aircraft into wind and despite the manifold dangers, brought it safely down on the heavy swell. Badly damaged and blazing furiously, the aircraft rapidly settled.

After ordeal by fire came ordeal by water. There was only one serviceable dinghy and this could not hold all the crew. So they took turns in the water, holding on to the sides. Once, the dinghy capsized in the rough seas and was righted only with great difficulty. Two of the crew succumbed from exposure.

An airborne lifeboat was dropped to them but fell some five hundred yards down wind. The men struggled vainly to reach it and Flight-Lieutenant Hornell, who throughout had encouraged them by his cheerfulness and inspiring leadership, proposed to swim to it, though he was nearly exhausted. He was with difficulty restrained. The survivors were finally rescued after they had been in the water for twenty-one hours. By this time Flight-Lieutenant Hornell was blinded and completely exhausted. He died shortly after being picked up.

Flight-Lieutenant Hornell had completed sixty operational missions, involving six hundred hours flying. He well knew the dangers and difficulties attending attacks on submarines. By pressing home the skilful and successful attack against the fierce opposition, with his aircraft in a precarious condition, and by fortifying and encouraging his comrades in the subsequence ordeal, this officer displayed valour and devotion to duty of the highest order.