Operation Jericho
Operation Jericho ("
Ramrod 564"), was allocated to
140 Wing,
RAF 2nd Tactical Air Force.
[10] Eighteen
de Havilland Mosquito FB Mk VIs, six from
No. 487 Squadron RNZAF (Wing Commander
Irving "Black" Smith), six of
No. 464 Squadron RAAF (Wing Commander
Bob Iredale), both being
Article XV squadrons. Six Mosquitos of
21 Squadron (Wing Commander Danny Dale) were to follow up in case the raid failed and bomb the gaol, killing the prisoners.
[11][c] A photographic reconnaissance (PR) Mosquito was laid on for the
Royal Air Force Film Production Unit (FPU), to film the raid. The raid was provisionally set for 17 February; the Mosquitos were to arrive over the prison at noon sharp, to catch the guards at lunch for the second wave to bomb them. The plan was divulged to the Resistance for them to tip off the underground in the gaol and to arrange for accomplices to be waiting outside.
[13]
Air Vice-Marshal Basil Embry, the officer commanding
2 Group, intended to lead the raid but was overruled and forced to stand down because he was involved in the planning of the
Invasion of Normandy.
Group Captain Percy Pickard, the
RAF Hunsdon station commander took over command, despite having limited experience of low-level attack.
[14][d] Each Mosquito squadron was to have an escort of one
Hawker Typhoon squadron,
174 Squadron and
245 Squadron from
RAF Westhampnett and a squadron provided by
Air Defence of Great Britain (the part of Fighter command not transferred to the 2nd Tactical Air Force) from
RAF Manston.
[16] A
plaster of paris model of the gaol was built, based on photographs and other details sent from France, a common practice in RAF planning.
[17] The model showed the prison as it would look at a distance of 4 mi (6.4 km) at a height of 1,500 ft (460 m); attacking at such low altitude needed careful timing to avoid collisions.
[14][e] Bomb load for the Mosquitos was two 500 lb (230 kg) Semi-armour piercing (SAP) bombs for the outer walls and two 500 lb (230 kg) Medium Capacity (MC) for the inner walls all fuzed for 11 seconds' delay.
[18][f] The first section of three aircraft from 487 Squadron were to attack the eastern wall at 12:00 at low altitude, using the main road as a guide onto the target, the second three to make a north–south attack on the northern wall once the first bombs had exploded. The first section of 464 Squadron RAAF would attack the south–eastern end of main building three minutes later and the second section would attack the north–western end.
[20]