'Firepump' was a British airborne operation by 11 men of the Indian 153^rd (Gurkha) Parachute Battalion in Brigadier M. R. J. Hope-Thompson’s Indian 50^th Parachute Brigade to land by parachute and prepare a landing strip near Fort Hertz in northern Burma (13 August 1942).

Up to 1942, Fort Hertz was maintained as an outpost of the Myitkyina Battalion of the Burma Frontier Force, and in the course of the 1942 Japanese 'B' (iii) invasion of Burma, a miscellany of retreating British and Indian soldiers remained in the Fort Hertz area. The military authorities in India had no direct contact with Fort Hertz during most of the summer of 1942.

Troops were parachuted into Upper Burma on 3 July 1942. Led by Captain J. O. M. Roberts of the 153^rd (Gurkha) Parachute Battalion, the men had orders to investigate the state of the Myitkyina area and then march 150 miles (240 km) to the north to Fort Hertz.

On 12 August 1942, Major Hopkins of the Indian 50^th Parachute Brigade overflew the Fort and discovered that it was, somewhat unexpectedly, still in British hands as Roberts had reached the fort some days before this. The landing strip at the fort not usable, however. On the following day, a party led by Captain G. E. C. Newland of the 153^rd Parachute Battalion dropped into Fort Hertz with engineering supplies, and by 20 August the airfield had been repaired sufficiently for its use. Lieutenant Colonel Gamble, the new commander of the area, arrived on that date and was quickly followed by one company of the 7/9^th Jat Regiment. The party led by Roberts was evacuated at about the same time, together with troops withdrawing from the Japanese advance into Burma.

The garrison of Fort Hertz, comprising various battalions of the British Indian Army and the Northern Kachin Levies, formed an isolated northern post of the Allied armies engaged in the Burma campaign. With the assistance of Kachin irregulars, the route to the north from Japanese-held Burma to Fort Hertz was defended against a series of minor attacks in 1942 and 1943.

In 1943 and 1944 the primary purpose of Fort Hertz was intelligence gathering and the protection of an airstrip which served as an emergency landing ground for transport aircraft flying the 'Hump' route between India and China over the eastern end of the Himalayan mountain chain. This same airstrip was also the sole supply line for Fort Hertz. Eventually there was also a radio beacon navigation checkpoint at the site.

Large-scale official training of the Kachin levies did not begin until August 1943, when a 'V' Force team was sent to Fort Hertz. A US advisory team of eight officers and 40 sergeants also flew into Fort Hertz. The US forces raised their own Kachin force, the Kachin Rangers, in the area of Myitkyina during 1944.

When Lieutenant General Joseph W. Stilwell’s Chinese 'X' Force started its advance to cover the building of the Ledo Road and the US-led Northern Combat Area Command operation, forces from Fort Hertz advanced on Stilwell’s left flank to capture Sumprabum, and then continued their advance toward Myitkyina, in the process capturing Tiangup and eventually linking with 'X' Force.

The operational forces at Fort Hertz were maintained solely by air for around 25 months between August 1942 and August 1944.