HCU (41 Base)

41 BasePosting to 41 Base (May 1944)

Having completed his technical training, Cecil was posted to “41 Base” in West Yorkshire on 27th May 1944 to train as part of a seven man crew on a four-engined heavy bomber.

“41 Base”

“41 Base”, in West Yorkshire, was the training base for No 4 Group, Bomber Command. It consisted of RAF Marston Moor along with its satellite airfields at RAF Rufforth, RAF Riccall and RAF Acaster Malbis.

It had three Heavy Conversion Units (HCU’s) which were responsible for teaching crews how to fly the four-engined heavy bombers:

  • 1652 HCU, based at RAF Marston Moor
  • 1663 HCU, based at RAF Rufforth
  • 1658 HCU, based at RAF Riccall

“Crewing Up”

The heavy bombers needed a crew of seven; pilot, flight engineer, navigator, wireless operator, bomb aimer, mid-upper gunner and rear gunner.

Each member of the aircrew had been taught their trade at specialist schools, either in the UK or overseas. Having completed their technical training, five of the trades, (pilot, navigator, wireless operator, bomb aimer and one of the air gunners) “crewed up” at an Operational Training Unit (OTU) and trained as a five man crew on two-engined medium bombers.

Once they were competent, the five man crew would transfer to a Heavy Conversion Unit, where they would be joined by a flight engineer and an additional air gunner (for the mid-upper turret position) to form a seven man crew for the heavy bombers.

AE Johnson's Crew

AE Johnson and his crew

Cecil “crewed up” with AE Johnson’s crew, which consisted of (left to right):

  • Roy Maurice Jenkins 1394968 (Wireless Operator)
  • Douglas Farrant Hadland 1616720 (Rear Gunner)
  • Gerald Basil Thomas 154955 (Navigator)
  • Allan Edward Johnson 61984 (Pilot)
  • Harry Coulton 152725 (Bomb Aimer)
  • Raymond Neale 1100968 (Mid-Upper Gunner)
  • Cecil Arthur Butler 1868746 (Flight Engineer)

Note: The service record of GB Thomas shows that he (and presumably the rest of the five man crew) was posted from 10 OTU, Abingdon to 41 Base on 18th May 1944; Cecil’s show that he was posted on 27th May 1944. Normally the flight engineer was posted two weeks before the crew from OTU so that he could get some flight training in before the crew arrived … so perhaps there were some crew changes prior to Cecil’s arrival.

Flying Log Book

Flight engineers who trained during this period confirm that Cecil would not have had any flying experience up to this point, although he may have spent a small amount of time at St Athan on a “link trainer” (flight simulator).

Sadly, Cecil’s Flying Log Book (RAF Form 1767), which recorded all flying activity, has been lost in time.

The log, which had to be countersigned by the commanding officer, provided a record of:

  • the date
  • the aircraft used
  • the pilot
  • the duty performed on the flight
  • the purpose of the flight
  • the flying time (split day / night)

An extract from a Flying Log Book [Courtesy of Paul Herod]

Training and Assessment

The four to six week Heavy Conversion course consisted of ground instruction, along with approximately 40 hours of flying, probably in a Handley Page Halifax.

Experienced instructors, normally crew who had completed their operational tours, would fly “dual” with the crew and then the crew would repeat the exercise “solo”.

A Handley Page Halifax

Crew positions in the Halifax were as follows:

AE Johnson (Pilot) sat on the port side on an upper flight deck.

CA Butler (Flight Engineer) sat next to the pilot, on a fold down seat, although his station, including the flight engineer panel, was positioned behind the pilot on the upper flight deck.

R M Jenkins (Wireless Operator) sat in a compartment, immediately below the pilot, facing forwards, with his equipment mounted in front of him.

G B Thomas (Navigator) sat forward of the wireless operator, facing the port side, with a large chart table in front of him.

H Coulton (Bomb Aimer) was stationed in the nose of the aircraft, forward of the navigator.

R Neale (Mid-Upper Gunner) was stationed in the dome shaped mid-upper turret which provided a 360 degree view over the top of the aircraft.

D Hadland (Rear Gunner) was stationed in the rear turret.

The Flight Engineer, Pilot and Navigator in a Handley Page Halifax  [Photograph © IWM CH 7903]

The HCU Training Schedule, included the following training exercises:

  • Familiarisation
  • Circuits and landings
  • Bombing
  • Fighter affiliation
  • Cross-country

With the help of instructors, Cecil was able to put into practice all the things that he had been taught in the classrooms at RAF St Athan.

Cecil’s first job was to work with the pilot to check the outside of the aircraft.

The external checks included ensuring:

  • that there was no visible damage, in particular to the working parts and leading edges of the airframe
  • that the tyres were in good order
  • that there were no coolant or oil leaks

It is understood that once these checks were complete, the pilot signed Form 700 to confirm the handover of the aircraft from the ground crew.

Cecil then clambered into the aircraft, with his parachute and “emergency repair” tool bag (spanners, pliers, wire, string etc) in his hands.

His next job was to carry out the internal checks including ensuring:

  • that the oxygen supply was functioning
  • that the internal latches were all secure
  • that fire extinguishers, axes etc were properly stowed

Having completed the internal checks he settled at his station, which on the Handley Page Halifax was behind the pilot; he would then carry out the pre-flight checks in conjunction with the pilot and ground crew.

Information regarding some of the checks and the fuel loads, pressures etc was recorded in the four page flight engineer log.

Bomber Command Log

The first page of the flight engineer’s log  [Courtesy of RAF Museum, London]

One by one, the four engines were started up and Cecil monitored the instrument readings on the flight engineer panel. When all four were warmed up, the pilot checked with the crew to ensure they were all happy with their equipment and that their oxygen and intercom systems were working.

He then taxied onto the perimeter track (“peritrack”) and awaited the signal for take off.

Cecil would be either sitting or standing beside the pilot, ready to assist him with the throttles, undercarriage and flaps; between them they ensured that the fully laden heavy bomber got off the ground and climbed to its allotted cruising height.

Having reached cruising height, he ensured that the aircraft maintained its optimum cruising speed, utilising the minimum amount of fuel (“flying for economy”). He also synchronised the propellers to minimise engine vibration and noise.

Throughout the flight, he monitored the fuel consumption, engine revs, oil pressures, coolant temperatures etc and logged them “at every change of flight or engine conditions and at thirty minute intervals”.

He monitored the amount of fuel in each of the wing tanks and used the fuel cocks to ensure that it was evenly distributed across the tanks;  this ensured that if one leaked, or was hit by enemy flak, there was sufficient fuel in the other tanks to keep the aircraft in flight.

The perspex astrodome above his head enabled him to ensure that they were clear of other aircraft (and to monitor for enemy aircraft during operational sorties).

Having completed their assigned exercise or sortie, Cecil assisted the pilot with the landing, shutdown and post-flight checks.

Any issues were reported to the ground crew using the Form 700 and the four page flight engineer log was handed in for review and signature.

An example of a Form 700 (date unknown)

Completion of Course

Having successfully completed their HCU training, the crew members were deemed competent enough for operational duty.


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