Donaldson was born in 1911.

He led 263 Squadron during both Norwegian expeditions.

In the morning on 25 April a lone He 111 bombed Lake Lesjaskog, this initial attack destroyed four Gladiators and injured three pilots including Squadron Leader Donaldson, who suffered from severe concussion. The attacker was one of a pair from Stab/LG 1, which reported seeing 15 biplanes and several other aircraft on the ground.
At Lesjaskog four more frozen-up Gladiators were destroyed by air attack at 13:05, but two others then got off, flown by Squadron Leader Donaldson (in N5633) and Flight Lieutenant R. S. Mills. Over the next two and a half hours these two would engage in six major combats over the lake.
Firstly at 14:00 both pilots attacked a Heinkel of Stab/LG 1 and brought it down to crash-land south of Vinstra, near Dombås.
Feldwebel Hans Gutt’s crew set fire to the aircraft, in which the badly injured wireless operator had shot himself. The survivors were subsequently captured, and the wreckage of this bomber was later inspected by British troops.
Both pilots then attacked another Heinkel from 6./LG 1, which was damaged, but made it back to Fornebu with two wounded aboard.
Donaldson and Mills were both airborne again during the evening, as the last five serviceable Gladiators were withdrawn from Lesjaskog north to a temporary landing ground, which had been prepared at Setnesmoen, just outside Aandalsnes. Donaldson was scrambled, and near the new base found a He 111 of II./LG 1, which had been attacking a steamer near Aandalsnes. This was believed to have been shot down into a ravine, but actually the very badly damaged bomber was almost able to reach Oslo/Fornebu before the engines failed and the crew baled out.
R. S. Mills was up for a third time before twilight, having a running fight with a Ju 88, but he had to make a force-landing having used up all his fuel and ammunition. As he was examining the fighter for damage, bombers appeared and destroyed it.

263 Squadron suffered heavily losses and was soon withdrawn back to Great Britain to be re-equipped.
On 21 May the squadron again landed in Norway. This time at Bardufoss in northern Norway after having flown off from the carrier HMS Furious.

Donaldson took part in the successful evacuation of fighters from Narvik on 8 June 1940 when he and nine other pilots from 263 Squadron landed their Gladiators aboard HMS Glorious. However this successful evacuation was avail when the carrier was sunk by the German battlecruisers Scharnhorst and Gneisenau later in the day with the loss of almost all aboard, Donaldson being one of them.

He was posthumously awarded a DSO and a DFC.

At the time of his death Donaldson was credited with 1 biplane victory.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1940
	25/04/40	14:00	1/2	He 111 (a)	Shared destroyed	Gladiator II	N5633	S Vinstra	263 Squadron
	25/04/40	14:00	1/2	He 111 (b)	Shared damaged	Gladiator II	N5633	Lake Lesjaskog	263 Squadron
1	25/04/40	a.m.	1	He 111 (c)	Destroyed	Gladiator II		Setnesmoen area	263 Squadron

Biplane victories: 1 and 1 shared destroyed, 1 damaged.
TOTAL: 1 and 1 shared destroyed, 1 damaged.
(a) He 111 of Stab/LG 1 shot down to crash-land south of Vinstra, near Dombås at 14:00. The badly injured wireless operator shot himself. Feldwebel Hans Gutt and the rest of his crew were taken prisoners after setting the aircraft on fire.
(b) He 111 of 6./LG 1 damaged shortly after 14:00 with two of the crew wounded.
(c) He 111 of II./LG 1.

Sources:
Fledgling Eagles - Christopher Shores with John Foreman, Christian-Jaques Ehrengardt, Heinrich Weiss and Bjørn Olsen, 1991 Grub Street, London, ISBN 0-948817-42-9
Gloster Gladiator Home Page - Alexander Crawford
The Commonwealth War Graves Commission