David Wylie travels north to visit one of the UK’s best underslung load specialists, Skyhook Helicopters, as the business supports the pour and formation of a 56m3 concrete pad from Scotland’s highest road
THE parent company of Skyhook is headquartered on the Isle Of Mull. TSL Contractors Ltd is a construction and civil engineering specialist, founded in 1979. Owner and MD Andrew Knight spotted a gap in the market for airlifting operations and formed West Coast Helicopter Services out of a hangar on Mull in 2014.
The division started out with a world record-breaking Eurocopter AS350 B3+ machine – Reg no G-LARR – to specialise as an air crane in underslung load operations. The Skyhook Helicopters branding has been used since 2015, the same year operations moved to Balfron Station, to the north of Glasgow.
As the division grew, a second machine was added in 2019 – another Eurocopter AS350 B3+ model. Now covering more than the west coast of Scotland, the division was relocated to Glenrothes, Fife in 2020. Last year, another multi-million-pound investment was made in another helicopter – same as the AS350 B3+ machine – now known as the H125 model as Airbus owns the former Eurocopter business.
Skyhook has remained focused on becoming experts in all areas of Helicopter External Sling Load Operations (HESLO). Examples of projects undertaken include peatland restoration, footpath restoration, ski-lift construction, power transmission projects, deer fencing, tree planting, and more recently firefighting and telecoms industry support.
Skyhook pilots are some of the most highly trained and experienced in Europe, and they are unique in that they have the only four pilots in the UK certificated to carry out very precision flying – achieved HESLO level 4 or higher – when undertaking lifting operations. They have equally certified in-house riggers for assembling bolted steel structures, such as Met-masts for windfarms, telecommunication masts and ski-lift pylons.
Sections can be lowered from the air directly onto the tower base bolts and upwards with no need for access tracks or heavy cranes and excavators on site. Skyhook can also provide a team of trained riggers to climb the tower as it is erected and guide pilots.
I met up with some of Skyhook’s team at the Cairnwell Pass on the A93 between Glen Shee, Perthshire and Braemar, Aberdeenshire. This is the highest main road in Scotland, reaching an elevation of 670m.
As a second generation of this family business, Charlie Knight was acting as one of the airlift supervisors on this job. Flying the Eurocopter AS350 B3+ is the highly experienced and utility rated pilot Henry Liddell, with 20 years’ experience and nearly 9,000 hours on various types of helicopters and operations. He has helped put nearly 4,500 hours on the one he is flying today, registration G-LBRR.
Charlie explained that before lifting operations can begin, he draws a decent size sample of Jet-A1 fuel from the mobile towed fuel bowser to check for possible water contamination in the fuel tank. Whilst this is being carried out, Henry is making his mandatory first use checks of his flying machine, paying particular attention to the condition of the main rotor and tail rotor blades, drives and subassemblies.
This machine is fitted with underslung lifting frame rated for a load of 1,400kg. For today›s operations, the team will be working with a 30m-long rope that hooks onto the lifting frame, and at the other end has a safety hook for the ground team to hook and unhook the lightweight aluminium upright skips that will hold the concrete material.
At the time of our visit, Skyhook was tasked with transporting 56m3 of concrete 300m vertical up to the highest point at Cairnwell. The plan was to dispatch five large capacity concrete mixer trucks from Braemar on day one, and the ground team would use their own aluminium skips to hold between 700 and 950kg – as the helicopter fuel burns off and the machine gets lighter resulting greater payload performance – for the freshly poured concrete. Day two would see three more truck loads to finish the job off. As this was going to be a continuous pour, Henry would have his work cut out for him, as he estimated he would be making around 130 rotations, requiring 6.5 to seven hours of flying time.
Henry commented they had perfect flying conditions, as it was a bright, cloudless and sunny day, with just a little bit of a headwind depending on his approach, and cool temperatures.
Since they are not allowed to carry passengers with an underslung load, the first rotation of the day was to drop off Charlie Knight and his co-worker, as they would be directing operations and handling the skips at the top of the mountain.
As the first mixer trucks arrive, the ground crew use IBC water containers to carry out dust control in the large hardstanding car park area, as the powerful downwash from the helicopter rotor blades is significant. Effective road management is also put in place – supported by Alba Traffic management – to ensure the helicopter is not flying over the A93 road traffic as it crosses the carriageway to the mixer trucks, and there is normally a well-timed additional mixer truck waiting in a holding area for this continuous pour.
As the first batch of concrete is hooked up to the helicopter, Henry quickly flies and navigates his Eurocopter AS350 B3+ through the valley and on reaching the top of the mountain he places the aluminium skip with pinpoint accuracy close to a waiting JCB 140 X, hired from Morris Leslie Group. At the controls of the 140 X is Sandy McDonald, owner of S22 Contracting, which is carrying out all civils work at the top of the mountain to create a new concrete base for a metal structure to be erected the following week.
Sandy McDonald explained the JCB is there for two reasons, the most important being safety, as the helicopter is flying near structures at the top of the hill, and secondly, around 40 seconds per rotation is saved, as this alleviates Henry from the time-consuming task of hovering his helicopter over the pour area as the JCB will simply pick up each skip and track a few metres forward to offer Sandy’s two ground workers the skip. They will then position the skip and pull the extra-long side lever handles and the freshly poured concrete will unload from the bottom dump skip and enter the shuttered and reinforced concrete pad that is being formed.
There is some respite from the intense flying, as the helicopter is hot-fuelled with the blades spinning at idle speed. This helicopter will burn approximately 180 litres per hour. Henry also manages a 20-minute rest break to stretch his legs as one of the scheduled mixer trucks is a little late in arriving mid-afternoon.
Henry explained Skyhook operate the very latest version of the Eurocopter AS350 single squirrel model, as it’s the B3+ model with slightly more performance than the standard B machines. And their new machine is the Airbus H125 (formerly known as the AS350 B3e). He also comments this model is a nice aircraft to fly. It›s very reliable, but can sometimes be quite tricky to fly on very accurate operations, but this challenge is also enjoyable. It is also said to be a hugely popular machine across Europe, for both VIP flying and this type of utility work where you need a helicopter to cope with hot and high altitude conditions.
Henry carries out a detailed pre-flight check, completes a technical flight log and will also give a verbal handover if another pilot is scheduled to fly it. The maintenance is carried out by a company in Blackpool, however plans are in place to bring this in-house at the firm›s Glenrothes flight base in the next few months. Also, when on wildfire fighting work, the engine can ingest some ash, which will need cleaned out more periodically.
Henry likes to get into a flying rhythm with the machine rated for 80 knots indicated when loaded. He has to factor in a ‘braking point’ to lose this speed at the top of the drop point and when unloaded an even faster descent with gravity assist! These key reference points are referred to as gates and are important – as the intense flying progresses throughout the day – to maintain a safe working consistency of rotation after rotation all-day long.
