The concept of a Pathfinder force to lead the way for the bombers was opposed by Sir Arthur 'Bomber' Harris because the expert pilots and navigators it would involve were exactly the men that he needed to lead the ordinary squadrons. But once ordered to organise such a unit, Harris appointed Donald Bennett, an Australian Wing Commander, to lead it. Bennett had undertaken many long distance lights during the 30s, and had served in flying boats commanded by Harris, so he was a known quantity. The Pathfinders' Mosquitoes and Lancaster’s were packed with the latest navigational and bomb aiming equipment, saving the main force crews the problem of target location. Air Vice-Marshal Donald Bennett (above) was a natural choice to lead the Pathfinder Force. Its job was to position marker bombs (below) accurately on the target.
Mosquitoes locate the target by 'Oboe' and drop parachute flares and bombs to mark the target. Extreme accuracy is vital at this stage because the bombers that follow will try to bomb on the aiming point. Waves of bombers arrive over the target and drop a mixture of high explosive (HE) bombs, land mines and incendiaries. The HE bombs blow off roofs and shatter windows. Lancasters and other heavy bombers shower the marked target with incendiaries. Many are dealt with by civilians but the civil defence forces are already being strained. The land mines have delayed-action fuses, so they explode after the bombers have left and hinder the efforts of the fire fighting and rescue forces.
By the end of hostilities there were 19 Pathfinder Squadrons, equipped with almost every type of aircraft found in the main bomber force. The squadrons were usually the first to be equipped with the latest navigation and bomb aiming aids, including GEE, OBOE and the airborne radar set H2S. Initially the Pathfinder Force (PFF) consisted of 5 squadrons, but by January 1943 the PFF had been expanded to become No 8 (Pathfinder Force) Group, ultimately consisting of 19 squadrons. The pathfinders were the first to arrive over a target, identify it and mark it with flares so that the main bomber stream had something to aim at. One problem was noted with this method was that of “target creep”, usually because the bombing would often extinguish the initial flares and the following bombers would then target the fires. One method of correcting this bombing error was to use different coloured flares, but it wasn’t until the development of the “Master Bomber” that the errors started to be corrected. The Master Bomber was a technique first used by Wg Cdr Guy Gibson during the dams raid where he found that passing aiming point information to his attacking force was of benefit. As part of the Pathfinder Force the Master Bomber would circle the target passing targeting information by VHF radio to the rest of the bomber stream, thereby ensuring a more accurate attack. There were very few bomber squadrons allowed to bomb at night independently, but such was the training and accuracy of 617 Squadron that they often marked and attacked their targets on their own. Many of the target marking techniques being developed by Wing Commander (later Group Captain) Leonard Cheshire VC who often flew an OBOE equipped Mosquito to mark for the squadron. He found that good as the Mosquito was for the role, it wasn’t fast enough for the extremely low level marking he wanted to use, especially against the V2 domed roof control bunkers in Northern France. He was eventually given a P51 Mustang to evaluate for the role which was more than adequate. On one raid he actually ordered the bombers to aim on his aircraft as he circled the target. With the advent of airborne radar in the shape of the H2S equipment, the targets could be marked even if it was completely obscured by cloud or smoke by the technique of “Sky-marking” using parachute flares. There were basically three types of flares; the coloured TI or target indicator flare, the high intensity illumination flare to light up an area to allow for accurate TIs and the parachute flare. Extra flares were carried which could be used to replace those flares extinguished or to correct the target creep. Pathfinder aircrew were allowed to wear a small gilt eagle badge on the left breast pocket flap, just below the medal ribbons on all uniforms except their working battledress, since this could mark them out as elite crews if captured. Squadrons No. 7 Squadron RAF - Stirling, then Lancaster No. 35 Squadron RAF - Halifax, then Lancaster No. 83 Squadron RAF - Lancaster No. 97 Squadron RAF - Lancaster No. 105 Squadron RAF - Mosquito No. 109 Squadron RAF - Wellington, then Mosquito - Oboe No. 128 Squadron RAF - Mosquito formed 1944 No. 139 Squadron RAF - Mosquito No. 142 Squadron RAF - Mosquito formed 1944 No. 156 Squadron RAF - Wellington, then Lancaster No. 162 Squadron RAF - Mosquito formed 1944 No. 163 Squadron RAF - Mosquito formed 1945 No. 405 Squadron RCAF - Halifax, then Lancaster No. 571 Squadron RAF - Mosquito formed 1944 No. 582 Squadron RAF - Lancaster formed 1944 No. 608 Squadron RAF - Mosquito formed 1944 No. 627 Squadron RAF - Mosquito formed 1943 No. 635 Squadron RAF - Lancaster formed 1944 No. 692 Squadron RAF - Mosquito formed 1944 83, 97 and 627 Squadrons were passed to 5 Group in April 1944 The PFF flew a total of 50,490 individual sorties against some 3,440 targets. At least 3,727 members were killed on operations.
