A Pathfinder Glossary

The Pathfinders of Bomber Command used a variety of techniques and tactics when marking targets for the Main Force. These were all referred to by codewords. Here is an alphabetical glossary of some of the many Pathfinder terms I’ve come across in the course of my research:

  • Backers-Up: Pathfinder crews scattered through the Main Force who dropped secondary target indicators (usually green) visually on the red primary target indicators. This was aimed at ensuring that the target remained marked for the entire attack, even after the primary markers had burnt themselves out.
  • Blind Marking: Aiming bombs or target markers by means other than visually – usually referring to the use of an electronic aid like H2S, Oboe or Gee.
  • Blind Marker-Illuminators: First Pathfinder aircraft on the scene during a NEWHAVEN attack who used H2S to drop illuminating flares and target indicators (usually green or yellow). The light provided by the flares could then be used by the Visual Markers.
  • Controller: Officer who is in R/T contact with the Pathfinder Markers and Illuminators, and W/T contact with the rest of the Main Force. The Controller decides which markers are accurate and instructs the Main Force crews accordingly.
  • Emergency Parramatta: Used where the Visual Markers could not see the aiming point due to cloud or haze. They would hold on to their markers and the Backers-Up would instead aim their secondary target indicators on the markers dropped by the Blind Marker-Illuminators.
  • Emergency Wanganui: Pathfinder aircraft carried a single WANGANUI flare for use where unexpected heavy cloud precluded the use of ground markers.
  • H2S: Airborne ground-mapping radar carried by bombers. Could distinguish built-up areas and most effective where a clearly-defined feature – such as a coastline – existed.
  • Illumination: Dropping of parachute flares to light up the target area, enabling the aiming point to be identified visually by Pathfinders or by the Main Force. Carried out by the Flare Force.
  • Main Force: ‘Ordinary’ rank-and-file Bomber Command crews.
  • Markers: Generic term for Target Indicators or Wanganui makers. Confusingly, could also refer to the crews actually doing the marking.
  • MUSICAL: Prefix codeword for raids marked by crews (usually in Mosquitos) using OBOE. Distributing marking Mosquitos throughout the bomber stream aimed to ensure that the target was always marked by primaries. Eg MUSICAL NEWHAVEN, MUSICAL PARRAMATTA or MUSICAL WANGANUI.
  • MPI: Mean Point of Impact. The estimated ‘centre’ of a cluster or target indicators, sky markers or bombs.
  • NEWHAVEN: A method of ground-marking whereby the target was first located by Blind Marker-Illuminators, then backed up by Visual Markers dropping Target Indicators. Since the markers were aimed visually this could only be used with clear weather prevailing over the target. If a Newhaven attack was impossible an Emergency Parramatta would be used instead.
  • OBOE: Navigation/blind-bombing aid using beams from two base stations in England. Extremely accurate but could be used by only a small number of aircraft at a time, so was used primarily to drop target markers.
  • PARRAMATTA: Classic area bombing technique where the primary markers (red or yellow) were dropped on the target by H2S-equipped Blind Markers. Backers-Up would then aim their (usually green) Target Indicators at the MPI of those primary markers for the benefit of the Main Force.
  • Primary Markers: Target Indicators or flares aimed at the Aiming Point itself. As opposed to Secondary Markers.
  • Release-point flares: Parachute flares, usually red with green stars or green with red stars, used in WANGANUI attacks. Also called skymarkers.
  • Secondary markers: Target Indicators or flares aimed at Primary markers. Dropped by Backers-Up to keep the target marked before the primaries burned out.
  • SUPPORTERS: Experienced Main Force crews briefed to go over the target and bomb at the same time as the leading Pathfinders, to ‘swamp’ the defences and make it difficult for radar-predicted flak to lock onto one individual aircraft.
  • Target Indicators: Ground markers consisting of a small bomb case which was set to burst at a certain height above the ground (3,000, 6,000 or 10,000ft), scattering up to 60 small ‘candles.’ The candles then ignited and cascaded slowly to the ground. Once on the ground they continued burning with a distinctive colour – red, green or yellow. Most burned for about three minutes but some burned, less brilliantly, for up to seven. Called ‘Christmas trees’ by the Germans.
  • Visual Markers: Pathfinder crews that identified the aiming point visually, and dropped their own markers (usually red) on it. Usually the most experienced crews in the Pathfinders.
  • WANGANUI: Blind bombing skymarking technique used when aiming point is covered in cloud. H2S-equipped aircraft dropped parachute flares and the Main Force aimed at the flares themselves (or the MPI of the flares if they were being scattered by the wind), bombing on a pre-arranged heading. Not terribly accurate and very susceptible to the wind. Flares used could variously be referred to as ‘skymarkers’, ‘release point flares’ or, simply, ‘Wanganuis’.

© 2013 Adam Purcell


NAA: A11343, 77/AIR. [No 467 Squadron] Pathfinder Force – Technique. Barcode 304281

Middlebrook, Martin (1973). The Nuremburg Raid