Moving the Mosquito

It’s been displayed at the Australian War Memorial for the past 20 years, but have you ever wondered how the Second World War Mosquito aircraft was installed or how conservators would get it out again?

Last year, the aircraft was moved to the Memorial’s storage facility in Mitchell to be cleaned and stored in environmentally controlled conditions.

Before it could be moved, it had to be painstakingly lowered from its position in Aircraft Hall and safely manoeuvred out of the heritage-listed building as part of a carefully planned operation.

“That was always going to be the biggest challenge,” said the Memorial’s Conservation Manager Laura Kennedy.

“It was the first item that was installed in Aircraft Hall when it was last changed over in 1999–2000, and all the objects and infrastructure, including a mezzanine level, were built and installed around it.

“Before we could lower the Mosquito, the challenge was to essentially reverse engineer how the other large objects were installed within the mezzanine, and how to demolish and disassemble the entire mezzanine structure which had been built below it.”

Originally conceived as a high-flying, unarmed photo-reconnaissance aircraft during the Second World War, the Mosquito saw service in a number of roles, including bomber, fighter-bomber, night-fighter, anti-shipping strike, trainer, torpedo bomber and target tug.

The Memorial’s DH98 Mosquito PR 41 is the only complete Australian-built Mosquito in existence. Rather than carrying weapons, it was equipped for long-range photographic reconnaissance duties. It could carry five cameras – one in the nose and four near the fuselage – and had a crew of two, a pilot and a navigator, who would also act as photographer and wireless operator.

To ensure the aircraft was disassembled and lowered safely, the collections team undertook months of planning and research.

“Whenever we move large objects like the Mosquito, there is always a lot of detailed planning that goes into it,” Kennedy said.

“The original 1941 floor slab in Aircraft Hall is 150 mm thick, so it’s quite thin, and the floor load rating is relatively low, so we had to be very strategic in our approach to lowering the aircraft.

“The floor itself was reinforced 20 years ago so that the mezzanine structure could be built to support the Mosquito and the mezzanine displays, but we also needed to know whether there was sufficient floor loading capacity to support the equipment that we needed to disassemble and lower the aircraft and move it out of the gallery because we needed to use a different approach to how it was installed.

“We knew the dry weight of a Mosquito, but not the actual weight of this particular aircraft, so the structural engineer and crane operator had to base their calculations on the worst case scenario.

“There were a number of complex stages to unpack in planning the demount: how to protect and support the aircraft while the mezzanine was disassembled around it, identifying equipment that had the capacity to lift the aircraft but not overload the slab, the order of disassembly, lifting and slinging strategies for each stage of disassembly, and ensuring there was adequate floor space for people, equipment and the aircraft during the work.

“One of the risks was whether the floor could support the weight of the cranes as well as the aircraft, and whether or not the cranes would be over their lifting capacity when they took the weight.

“The wing itself is 1.2 tonne and the fuselage is 2.8 tonne, but we couldn’t confirm the actual weight of the aircraft until the cranes took that weight, so the first day was always going to be a really big day for us because it would either work, or we’d find out that it wouldn’t, and then we’d have to start again completely from scratch.”

The collections team had to examine records and manuals as well as previous restoration work to ensure the aircraft could be safely lowered and moved before any work could begin.

“The aircraft itself underwent a full restoration process over 20 years ago,” she said.

“It is made of timber that was in very poor condition, so we were relying on the quality of that restoration having maintained its integrity so that when we did lower it the aircraft would not break.   

“The main area of concern was the intersection between the wing and the fuselage; the fuselage must be lifted from the wing and a brace installed within the gap to mitigate the risk of the laminated timber structure failing.  

“We spoke to an aircraft engineer who was involved on the periphery of the project about how to assess the integrity of the object, such as knocking on the timber to see if it sounds solid or drummy, and once we assessed it and reviewed all the documentation, we were confident that the aircraft was going to be in a sufficiently stable condition that the risks of it breaking were minimal.”

The engines were removed first, to reduce the overall weight of the airframe.

The next challenge was how to support the aircraft while the mezzanine structure was disassembled beneath it.  Two cranes were used to support the airframe from the engine mounts while the remaining structural steel was removed.

“The aircraft can be separated into two main sections – the wing is one piece, and the fuselage is another – and once it was lowered our aircraft technician, Kim Wood, could get into the fuselage and undo the bolts to separate the two,” Kennedy said.

Once the aircraft was lowered using mast hoists, the collections team could take it apart so that it could be manoeuvred out of the building and safely transported to Mitchell. It took about a week to disassemble.

“The wing itself takes up a huge cavity of the forward section of the fuselage, and there’s only about 20 cm worth of what looks like structure above the top of the wing so we had to be really careful,” Kennedy said.

“The wing and fuselage were separated using mast hoists at either end, with a spreader bar between and the fuselage slung at four points.  The fuselage was set down on a custom trolley and the wing was then moved out on trestles and artillery trolleys.

“We use a 22-tonne Franna crane, which is really mobile, to lift the objects up and onto either flat deck trucks or semi-trailers.

“The wing is over 15 and-a-half metres long so that required a 45-foot semi-trailer, and detailed transport logistics with the crane and haulage companies.”

A specialised team of collections staff also acted as spotters, ensuring the aircraft was moved carefully and safely.

“Whenever we are doing a lift we have a crane operator and a dogman,” Kennedy said.

“Everybody involved knows the dogman is in charge and they instruct the crane operator and collections team.  Everyone has a role. If you see something – the object is about to hit a wall, or you are running out of space, or something is not moving the way you expect it to – you yell out ‘stop’, and the team reassesses the job and rectifies the issue.

“These jobs can take some time to do, but they are done with the utmost care.  It’s critical that we protect the collection and people’s safety so if the job takes longer then that’s what’s required.

“It couldn’t have gone better. Everyone was so careful in the disassembly of the objects and respectful of each other and the material they were handling and hauling.

“And that’s the biggest priority throughout: people’s safety and protection of the collection. All the factors we consider in the planning, and the decisions we make, relate to how can we avoid damaging the collection and make sure that everyone is safe in the process.

“We are very fortunate that we have people in Collection Services who have been doing this sort of thing for a very long time and are highly skilled in moving large and complex collection items.

“There’s a lot of strength and expertise within the team and having that knowledge was completely essential to our success …

“I’m so proud of everyone for what they were able to achieve; I’m proud to have been part of it, and I’m privileged to work with such an amazing team.”