page_title: Short Sunderland
section_title: Access and servicing
hierarchical_section_title: Short Sunderland / Design / Access and servicing
caption_attribution_description: English: Royal Air Force Operations in the Far East, 1941-1945. A Short Sunderland GR Mark V of No. 205 Squadron RAF Detachment, moored off Direction Island, Cocos Islands, about to be refuelled from a petrol tanker embarked on board a Tank Landing Craft Landing Craft, Mechanized(?).
context_page_description: The Short S.25 Sunderland was a British flying boat patrol bomber, developed and constructed by Short Brothers for the Royal Air Force. The aircraft took its service name from the town and port of Sunderland in North East England.
  Developed in parallel with the civilian S.23 Empire flying boat, the flagship of Imperial Airways, the Sunderland was developed specifically to conform to the requirements of British Air Ministry Specification R.2/33 for a long-range patrol/reconnaissance flying boat to serve with the Royal Air Force. As designed, it served as a successor to the earlier Short Sarafand flying boat. Sharing several similarities with the S.23, it featured a more advanced aerodynamic hull and was outfitted with various offensive and defensive armaments, including machine gun turrets, bombs, aerial mines, and depth charges. The Sunderland was powered by four Bristol Pegasus XVIII radial engines and was outfitted with various detection equipment to aid combat operations, including the Leigh searchlight, the ASV Mark II and ASV Mark III radar units, and an astrodome.
  The Sunderland was one of the most powerful and widely used flying boats throughout the Second World War.
context_section_description: The Sunderland was usually entered through the bow compartment door on the left forward side of the aircraft. The internal compartments—bow, gun room, ward room, galley, bomb room and the after compartments—were fitted with swash doors to keep them watertight to about two feet (610 mm) above normal water level; these doors were normally kept closed. There was another external door in the tail compartment on the right side. This door was intended for boarding from a Braby (U-shaped) pontoon that was used where there was a full passenger service mooring alongside a wharf or similar. This door could also be used to accept passengers or stretcher-bound patients when the aircraft was in the open water; this was because the engines had to be kept running to maintain the aircraft's position for the approaching vessel and the front door was too close to the left inboard propeller. Normal access to the external upper parts of the aircraft was through the astrodome hatch at the front of the front spar of the wing centre section, just at the rear of the navigator's station.
  Bombs were loaded in through the "bomb doors" that formed the upper half walls of the bomb room on both sides. The bomb racks were able to run in and out from the bomb room on tracks in the underside of the wing. In order to load them, weapons were hoisted up to the extended racks that were run inboard and either lowered to stowages on the floor or prepared for use on the retracted racks above the stowed items. The doors were spring-loaded to pop inwards from their frames and would fall under gravity so that the racks could run out through the space left in the top of the compartment. The bombs could be released locally or remotely from the pilot's position during a bomb run.
  Normally, the weapons were either bombs or depth charges and the racks were limited to a maximum of 1,000 lb (450 kg) each. After the first salvo was dropped, the crew had to get the next eight weapons loaded before the pilot had the aircraft positioned on the next bombing run. The fixed nose guns (introduced when in service with Australian units) were removed when the aircraft was on the water and stowed in the gun room just aft of the bow compartment. The toilet was in the right half of this same compartment and stairs from the cockpit to the bow area divided the two.
  Maintenance was performed on the engines by opening panels in the leading edge of the wing either side of the powerplant. A plank could be fitted across the front of the engine on the extensions of the open panels. A small manually started auxiliary petrol engine, which was fitted into the leading edge of the right wing, powered a bilge pump for clearing water and other fluids from the fuselage bilges and a fuel pump for refuelling. Generally, the aircraft were reasonably water tight, and two people manually operating a wobble pump could transfer fuel faster than the auxiliary pump. In sheltered moorings or at sea, fuelling was accomplished by a powered or unpowered barge and with engine driven or hand powered pumps. At regular moorings, there would be specially designed refuelling barges to do the job, normally manned by trained marine crew. These vessels could refuel many aircraft during the course of the day. Handling of the fuel nozzles and opening/closing the aircraft fuel tanks would normally be an aircraftman's task.
  Airframe repairs were either effected from the inside or delayed until the aircraft was in a sheltered mooring or beached. One serious problem that beset the aircraft was that the heat-treated rivets in the hull plates were susceptible to corrosion after a period in salt water (depending on the quality of the heat treatment process). The heads would pop off from stress corrosion, allowing seawater to leak into the bilges. The only option was to haul the aircraft out onto the "hard" and replace them, usually at the cost of many additional heads breaking off from the vibration of the riveting.
caption: A Short Sunderland GR Mark V of No. 205 Squadron RAF Detachment, moored off Direction Island, Cocos Islands, about to be refuelled from a petrol tanker embarked on board a Tank Landing Craft
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