RESULTS OF TRIALS OF AAD. TYPE A. - MIDDLE WALLOP - 22/11/40. 10
Five hundred modified bombs arrived on the station from Chorley at
about 22.00 hours on 21/11/40. These bombs were not fitted with
detonators, and it was not possible to unpack, fuze, and exchange bombs
in time to use a load of these bombs in time for the trial the following
Previous to this the armourers of 420 Flight had modified half a
load (80 bombs) by firing the Bickford fuze initiating cap. It was
decided to carry out a trial with a load consisting of these 80 bombs,
together with 80 unmodified bombs. The reasons for taking this decision
(1) The extreme urgency of the trial. It should be noted that
it was quite impossible to carry out the trial on the 22nd
with a full load of modified bombs owing to lack of time.
(2) The weather was excellent and all the necessary arrangements
for the trial had been made.
(3) The containers had been so modified that the lids could not
come off until they were clear of the aircraft.
(4) Tests have shown that "flash back" causing premature
detonation only ocurred in about 1 per cent of bombs.
After consultation between G/C Rowley, F/Lt. Burke and D.Arm D's
representative, it was decided to accept the slight risk of premature
detonation (which could not occur, as previously, with the bomb in contact
with aeroplane) in hope of being able to clear the apparatus for
operational use on the night of the 22nd in accordance with the Secretary
of State's expressed wishes for getting into action against the enemy at
the earliest possible date.
On the morning of the 22nd a full test was carried out of the
electrical release gear, after which the work of loading the 160 mines on
to the carriers was started. This is a long job and the men had had no
previous experience in fitting the containers to the modified carriers.
The aircraft, complete with photographic aeroplane, another Harrow
carrying observers, and escorting Spitfires set out at about 14.15 hours,
but had to return owing to enemy being reported in the vicinity.
The aircraft set off again at about 16.30 without the photographic
aircraft as the light was now too bad. The curtain was laid at about
17.00 hours from about 5,000 feet. Results were:-
(1) The mines left the aircraft as they should, regularly, evenly
and forming a very impressive looking curtain.
(2) After a certain number had been released, there was a premature
which appeared to take place some distance behind the laying
aircraft. This was followed by a second, rather closer, and
a third which looked to be some distance away. There was a
considerable number of mines between each premature.
(3) Although the curtain as a whole was regular fifteen parachutes
were considerably above the level of the remainder and two
below. Of the high ones, three were probably due to the
weak link resulting from the necessary use of a double breaking
link. This is a modification necessitated by errors in manu-
facture. The two low ones were due to delayed opening of their
(4) On returning to the aerodrome the pilot of the laying aircraft
reported feeling his tail lifted by the prematures and that
after the third of them he switched off the laying gear. An
observer in the laying aircraft said that he noticed a small
tear in the fabric. The slipstream got into this tear, and
on the way home, removed much of the fabric from one side of
the aircraft. From a superficial examination it does not
appear that any damage has been caused to the structure of the
(5) One mine on the bottom layer was found to have hung up in a
similar way to that which caused the accident on 26/10, but on
this occasion the modification to the rack and aircraft were
effective and the pin was not withdrawn from the lid of the
container. The apparatus therefore remained in a safe con-
- (2) -
(1) With unmodified mines flashback may result in a definite danger
(2) The modifications to carrier and aircraft do ensure that there
is no danger from "hang ups",
(3) Although these modifications do ensure that the mine is clear
of the aircraft before the lid is free to come off, the blast
effect from a premature may still cause damage to a metal.
covered aeroplane although such damage is not likely to be
serious and should be negligible on a fabric covered aeroplane,
(4) It is recommended that a further trial should be carried out as
as soon as possible with modified mines.
(Signed) H. Rowley. G/Capt.
(Signed) J. W. Homer.W/Cdr.
(Signed) P. L. Burke, F/Lt.
(Signed) W. Rathbone, F/Lt.
1. To get Harrow K. 7020 repaired by R.A.E.
2. To collect Harrow K. 6993 modified for operational use
from R.A.E. on Monday 25/11/40.
3. To carry out a further "live" drop on Tuesday 26/11/40.
4. If trial successful, operate on Tuesday night.