Target indicator

Target indicators falling over Berlin during a raid on the city

Target Indicators, also known as target markers or TI's for short, were flares used by the RAF's Bomber Command during World War II. TI's were normally dropped by the Pathfinders on the target, providing an easily seen visual aiming point for the following bombers to aim at. After their introduction, the use of TI's expanded to include en-route markers to gather up lost aircraft, additional drops of TI's to keep the target lit over long periods, and various changes in technique to address German defences.

The use of TI's allowed the RAF to concentrate its advanced navigational systems in the Pathfinder units. Most widely used were the H2S radar and Oboe system, the former requiring considerable training to be useful, the latter able to guide only a single aircraft at a time. The limited number of navigational units meant that spreading them through the force would have limited effects. By concentrating these in a single Group and having them drop TI's, the accurate fixes could be used to guide the entire attack. The same basic system had been used by the Luftwaffe's Kampfgruppe 100 during The Blitz, for similar reasons.

Target Indicators were available in various colours, and during a raid bomb aimers would be instructed by the Master Bomber to drop their bombs on the target indicators of a specified colour, marker aircraft carrying different colours should the initial target indicators be dropped off target. The first target indicators could be cancelled over the radio by the Master Bomber and the Marker crews instructed to drop new target indicators of a different colour, until the correct aiming point was correctly marked. The Main Force bombers would then be instructed by the Master Bomber to bomb the colour of the most accurate target indicators.

Target Indicators could be fuzed for both air and ground burst, the air burst markers - referred to as 'sky marking' by the RAF - resembling bunches of grapes or upside down fir trees when detonated in the air. These the Germans called 'Christmas trees' due to their shape.

Marking of targets was carried out by the following methods:

• Newhaven – target marking blind using H2S then with visual backup marking
• Parramatta – target marking by blind dropped ground markers - prefixed with 'Musical' when Oboe-guided
• Wanganui – target marking by blind-dropped sky markers when ground concealed by cloud - prefixed with 'Musical' when Oboe-guided

The code words were initially chosen by asking three Bomber Command personnel in the operations room where they came from. One was from Newhaven, England, one from Parramatta, New South Wales, and one from Wanganui, New Zealand.

Oboe was usually carried by Pathfinder de Havilland Mosquitoes.