5 minute read
Stuck in the Mud
After a rather wet landing due to a hydraulic fault, a Chinook from RAF Benson found itself unable to fly itself out. REME personnel from 1 Regt AAC were called out as part of the team to get it back in the air.
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“…sunk to its belly and the wheels were almost completely submerged in the soft soil. The aircraft was no longer able to fly itself out”
The Royal Engineers laid a track on top of the ground for the SV(R)s to drive on Preparing for the SV(R)s’ arrival and subsequent lift
CH47, a Chinook from RAF Benson was on a routine flight as part of pilot training. They were flying over Wantage when the aircraft had a hydraulic fault. The pilot followed their FRCs (Flight Reference Cards) and landed immediately. The CH47 landed safely in a nearby field, which looked to be a suitable grass field. Unfortunately, the field was completely saturated with water and had extremely soft topsoil. The aircraft wouldn’t be able to go anywhere until it was repaired.
After all the necessary processes had been followed and an engineering team called out, the fault on the aircraft was rectified, making the aircraft fit to fly. However, it had now sunk to its belly and the wheels were almost completely submerged in the soft soil. The aircraft was no longer able to fly itself out.
The reason it couldn’t fly itself out is the potential for suction on the aircraft to cause stress on the aircraft frame and most concerning was the potential for ground resonance. Since the aircraft was safe in a field in the UK, it was deemed that the safest solution would be to call JART (Joint Aviation Recovery Team). Once JART was informed, they sprang into action, deploying a team to head to the sight to assess the situation and formulate a plan. They also contacted other agencies including the Royal Engineers, civilian suppliers, and 1 Aviation Brigade. 1 Regt was put on 12 hours-notice to move.
On Saturday 9 January, Lt Tallis, Cpl Maylor and LCpl Whiten deployed from RNAS Yeovilton with one SV(R) and one white fleet car. They headed to RAF Benson where they parked the SV(R) and met up with another SV(R) deployed from JHC Flying Station in Wattisham. At 1100hrs, the team deployed out to the stricken aircraft. The area of operation was a large open grass field with the aircraft in the centre; there were two sheets of white matting rolled out either side of the aircraft and two tents located by the gated entrance to the field. There was no vehicle access into the field due to the ground conditions.
Upon arrival, the REME team were welcomed by the JART personnel. The team was quickly involved in the planning of the aircraft recovery. Giving key information to JART’s seniors, from where to lay the tracking to the lift plan itself. The proposed lift was to simultaneously lift both rotor heads of the aircraft. The team immediately set about adding value to the plan, going over the lift calculations. The plan to get the SV(R)s to the aircraft was for the Royal Engineers to lay a track on top of the ground for the SV(R)s to drive on. The drivers were directly involved with this, giving guidance on the turning circles and the best ways to approach the aircraft for the lift. As the lift itself was complex and the ground being less than ideal, lifting platforms were also erected to provide better lifting foundations.
Moving into position for the lift
It was an early start to make sure that we got to the site at the start of the day. The final parts of the trackway were being laid and the SV(R)s would soon be needed for their critical role.
After the position of the final weight distribution mats were positioned, the SV(R)s were then ready to move into place. Due to the limited spacings around the area, one had to reverse from the gate, down the 600m of track to the aircraft to ensure it was in the right place.
Once the vehicles were in place, JART cleared everyone who wasn’t required to a
distance. They wanted as few distractions or personnel around the aircraft when it lifted as possible, due to the safety implications. This was the key point and it didn’t help that the wind had picked up, which could potentially cause the CH47 to become unstable once lifted.
Once the team were happy, the cranes in place and a lift brief conducted, they were able to start the lift.
It was a slow process - one of the SV(R)s had to be re-set and adjusted due to technical issues that came up - but eventually they were able to lift the Chinook.
It was definitely a sight to behold; a fairly big helicopter being lifted clean off the ground by two vehicles with cranes on them is not something you see every day and it was great to know that REME played a key part in it.
At that point it was in the air and safe so the JART workforce started their task of creating a distributed and supporting foundation for the wheels to rest on. This involved using blocks to fill in the hole, using French oak wood (used for its toughness) to spread the load of the wheel across a bigger surface area around the hole and then finally topping the holes with heavy duty weight distribution mats which added extra security to the ground.
After all that was done to the standards required, the aircraft was then placed down and did not sink any further than it should have, success! It was now on a stable platform and would be able to lift itself out when the time was right.
The proposed lift was to simultaneously lift both rotor heads of the Chinook
Working quickly to fill the holes Moving the blocks and mats into position to place in the holes
“Once the team were happy, the cranes in place and a lift brief conducted, they were able to start the lift”
