The Boeing Chinook
The Boeing CH-47 Chinook Helicopter entered RAF service in November 1980. Throughout its 40 years of service the Chinook has made an immeasurable contribution to the Service, operating in every major conflict since the Falklands War, and delivering disaster relief and supporting communities across the UK. As a multifunctional workhorse, the Chinook is the backbone of Britain’s tactical logistics.
So what is the Chinook? It is a 2-engine multi-purpose twin rotor transport helicopter that was primarily developed for troop and equipment transport.
The twin rotor aspect is the most recognisable aspect of the Chinook. However, it was not a novel design. The RAF’s earlier Bristol Belvedere helicopter also used this system. So, what is the reason for it? A helicopter with a single rotor will have the tendency to rotate along the movement of the blades, a bit like a hammer thrower who rotates with the chained ball. Most helicopters have a tail rotor which pushes back, keeping the helicopter stable. Pushing harder or relaxing allows the helicopter to turn left or right. With two rotors rotating in opposite directions the need for a tail rotor is eliminated, allowing all power to be used for lift and thrust.
Two turboshaft engines were placed on either side of the rear pylon. They each had around 2,200 hp each, around the same as a late-war Spitfire, but a modern Chinook now has twice that. Turboshaft engines are essentially jet engines but they are connected via gearbox and several shafts to a combining gearbox in front of the rear pylon. From here shafts go to both rotors which have their own gearbox. These gearboxes reduce the engines’ speed of around 15,000rpm to the rotors’ much calmer rotational speed of 225rpm which gives the Chinook its distinctive ‘wokka’ sound. Also, if one of the Chinook’s turboshaft engines fail, the other can drive both rotors.
What’s more, the ability to adjust power to either rotor makes it able to carry more weight in the front or back of the helicopter. That is an important benefit to cargo lifting and dropping. It also allows the Chinook to perform one of its trademark moves, ‘the pinnacle’. This manoeuvre sees the Chinook setting its rear wheels onto a ridge or cliff edge with the front still in the air. It allows troops on or off the helicopter while it hovers and looks incredible.
Also instantly recognisable is the large pylon at the rear. The rear rotor is placed higher than the front to reduce the air disruption from the front rotor on to efficiency of the rear rotor. The Chinook’s automatic flight control system (AFCS) stabilises and provides autopilot functions, making the Chinook a relatively ‘easy’ helicopter to fly.
The design is optimised for maximising internal space. The fuselage is 15.25m long with the cockpit at the front, with a door to each side, a ramp on the other end, and a massive cargo bay in between. It’s 9.3m long, 2.29m wide and 1.98m tall, so big enough to take a vehicle or up to 24 stretchers. It had a maximum payload of around 10,000 lb (4,500 kg) though current versions can carry twice that much. Beneath the airframe are three external hooks that can be used individually or together.
The Chinook is lightly armoured, protecting it against small arms fire from below. There is also the ability to place machine guns in the side doors and at the rear. Modern Chinooks carry sophisticated anti-missile defences.
It was these design features that interested the American armed forces when they were looking for a new helicopter. Back in 1956 a replacement was sought for the H-37 helicopter, license-produced in the UK as the Westland Wessex. Vertol, later taken over by Boeing, submitted their twin rotor Model 107, which was chosen. The US Navy ordered it as the CH-46 Sea Knight but the US Army wanted a larger helicopter. The result was the Chinook as we know it today.
It was taken into service in 1962 by the US Army and became an important workhorse during the Vietnam war. It was used to carry heavy loads such as artillery guns to remote jungle areas or to recover downed aircraft. Its operational success led to its adoption by forces around the world. Well over a thousand Chinooks have been delivered to friendly armed forces such as Australia, Egypt, Greece, Iran, Italy, Japan, Morocco, the Netherlands, Singapore, Spain, Taiwan, Thailand, Turkey, South Korea and of course the United Kingdom.
The UK ordered 30 CH-47C ‘choppers’ as the Chinook HC1, which stands for Helicopter, Cargo, Mk 1. No.18 Squadron was the first operational squadron to be equipped with the Chinook in August 1981. A few months later the Falklands conflict erupted, and the Squadron was soon involved, flying stores and supplies to ships of the task force being assembled at Devonport. This included flying a 5-ton propeller bearing to HMS Invincible at sea in the English Channel, having very publicly departed Portsmouth the day before, thus avoiding an embarrassing return to port for repair.
Helicopters were to play an important part in any operation to recapture the Falklands, but the Royal Navy lacked a heavy lift helicopter and the RAF’s Chinooks were the only aircraft that could fulfil this capability gap. Six aircraft were rapidly prepared to join the Task Force, receiving modifications which improved the aircrafts’ survivability and operational capabilities. This included the installation of chaff dispensers, infra-red flare decoy dispensers, radar warning receivers and fittings for a machine gun. Four Chinooks were carried on board the Atlantic Conveyor cargo ship toward the Falklands.
One Chinook stayed on Ascension Island, the staging post between Britain and the Falklands. A Soviet spy ship was anchored near the island, and it was suspected that they were passing on information to the Argentinians. The ship had a large white superstructure housing all its aerials. A Chinook pilot offered to fly out in his helicopter to donate a bottle of malt to the Russian captain and then perhaps inadvertently ‘blast the superstructure and aerial to blazes’ with his downwash. It remained a plan. Luckily, as it would later appear that the Soviets had not been helping the Argentinians.
While the soldiers landed on the Falklands on 21 May, the Chinooks stayed on board. Few people understood the capability of the Chinook until it was too late. The Chinook’s lifting ability was almost five times that of the next biggest helicopter employed, the Sea King, and it had been envisaged that Chinooks would ferry troops across the difficult terrain, thereby keeping them fresh for battle and bring them into action quickly.
However, it took until 25 May when the first Chinook ‘Bravo November’ was made ready. After several ground runs of her engines she departed to conduct an air test. Shortly after taking off, the Atlantic Conveyor found itself under air attack and the three remaining Chinooks were lost in the fire. The loss of the Chinooks meant that the planned swift movement of troops across the Falklands could no longer take place. The Royal Marines and Paratroopers would now have to largely march or yomp or tab their way across the Falklands.
Unable to return to Atlantic Conveyor, Bravo November landed on the crowded deck of the aircraft carrier HMS Hermes, where her presence was not welcome. The ship’s captain threatened to have the Chinook pushed overboard if it was not removed because it would hamper the carrier’s ability to mount its own air operations. After an overnight stay the aircraft departed for the bridgehead at San Carlos.
With only one operational aircraft, No. 18 Squadron quickly had to reorganise itself. Ground and air personnel were selected but all the spares, manuals, servicing tools and equipment had been lost, and without this equipment it was not known how long the aircraft would remain serviceable.
The groundcrews spent the first three days sleeping in the open in freezing conditions. For the rest of the campaign, they continued to keep the aircraft airworthy despite the lack of equipment and tools. Chief Technician Tom Kinsella having lost the servicing paperwork for the aircraft, used an exercise book as a log book. This document, now in the Museum’s collection, records how after every day flying, Tom logged the defects, that would likely have grounded the aircraft under normal operation circumstances, servicing conducted and repairs made, ending each day ‘aircraft ‘s’(afe) to fly until receipt of spares’.
On 30 May the Chinook suffered an oil leak in its gear box. With no spares to repair it, Tom provided the crew with two gallons of oil with the instructions that if the situation became severe to put down and top up. With that he signed the aircraft as fit to fly: ‘I should have never let it go, but, I am convinced I would have been overridden’.
That night the weather was poor with frequent snow showers. The plan was to capture the prominent feature of Mount Kent which dominated the routes of advance from San Carlos but also overlooked the Argentinian defensive positions around Stanley, the capital of the Falklands. Bravo November carried three 105mm guns (two carried internally and one underslung).
On the return flight, the aircraft suffered an altimeter failure and hit a body of water. The rotors wound down as the engines ingested water. Believing the aircraft had crashed, co-pilot Andy Lawless prepared to evacuate by jettisoning his door. Miraculously the aircraft engines recovered, and the aircraft flew off the water.
The door which had been jettisoned contained maps and vital Identification Friend or Foe (IFF) codes to be used on the return. Without the IFF codes the British Rapier anti-aircraft missile batteries might have mistaken Bravo November as an Argentinian Chinook. The crew needed to make the Rapier batteries aware of their approach without appearing hostile, what is termed lame duck procedures, which the pilots did by turning on and off their lights to show that they were friendly. For his efforts on Mount Kent, pilot Squadron Leader Dick Langworthy was awarded the Distinguished Flying Cross (DFC).
The following day a thorough inspection was made of the aircraft to look for damage. Apart from some slight damage to the ramp and aerials the aircraft was still deemed serviceable and was ready to return to operations. The cause of the oil leak was identified, and a temporary repair made which stopped the leak for the remainder of the campaign. The cockpit door, however, could not be replaced and for the rest of the campaign the sole Chinook flew without the left-hand cockpit door which Andy Lawless described as ‘bloody cold’.
Despite the discomfort to the aircrew, the missing door would two days later save the aircraft from near disaster. As crew member Tom Jones recounted ‘…there were artillery guys attached to the marines, on the high ground to our left. They were about to open fire because they thought BN was an Argentinian Chinook, and then one astute corporal said “Wait a minute, hang on, no, it’s ours, it hasn’t got a door in the left hand side of the cockpit.” So what happened disastrously nearly a day before, we suddenly found out saved our lives…’
Bravo November continued to fly support helicopter operations for the remainder of the war, moving troops, supplies and ammunition in support of the ground forces as they battled toward Stanley. Tom Kinsella remembered that the morale was very high despite all the problems encountered in keeping BN operational, ‘We didn’t want to be reinforced, we wanted to see this thing through ourselves’. Which they just managed to do, two hours after the Argentinian surrender on 14 June a second Chinook arrived on the Falklands. Ironically following the surrender, No. 18 Squadron groundcrew removed the door from a captured Argentinian Chinook and fitted it to Bravo November. It would fly for many years with its ‘Argentinian door’.
During the 18 days ashore, Bravo November had flown everyday bar one, carried 2,150 troops, 95 casualties, 550 prisoners of war and 550 tons of stores. In a footnote in the RAF’s official history, it was noted that the tonnage was more than the ‘total carried by an entire squadron of Sea Kings for the same period’. An amazing achievement considering the scarcity of supplies, equipment, and manuals available to the groundcrew.
As said, Sqn Ldr Dick Langworthy received the DFC but the long career of Bravo November would see a further three pilots awarded the DFC while flying it. The arrival of Britain’s most famous helicopter to the RAF Museum Midlands is therefore a privilege and a most welcome addition to the Museum’s collection.
The achievements of that sole Chinook concreted the Chinook’s reputation. Ever since, the Chinook has always been a first-choice aircraft whenever the British armed forces have been called upon. That became evident during the Gulf War of 1991.
The Chinook was now considered a vital tool to move troops into the region, and toward their starting positions, and once the ground offensive had started, to keep them supplied as they moved deeper into Iraq and Kuwait. It was a Chinook which was used to transport a Special Air Service (SAS) patrol on the infamous Bravo Two Zero mission. In the aftermath of the conflict Chinooks delivered food and supplies to thousands of Kurdish refugees from Iraq.
During the mid-1990s, Boeing upgraded the existing HC1s to the HC2 standard with more powerful engines, improved avionics, infrared jammers, missile approach warning indicators, chaff and flare dispensers, a long-range fuel system and machine gun mountings.
In 1999 the Chinooks were instrumental in bringing in NATO peacekeeping forces into Kosovo after Yugoslav forces retreated. They also transported Kosovar refugees to safety and brought supplies and relief to the stricken country. The next year the Chinooks were again in action when they evacuated thousands of civilians from Freetown in Sierra Leone.
In 2003 they received the ability to operate in darkness with better navigational units, thermal imagers, moving map displays and night vision goggles. During the invasion of Iraq that year, a formation of five Chinooks spearheaded a joint forces assault with the US Marines on the Al Faw Oil refinery to prevent an act of environmental terrorism by Iraqi forces. Over the next three days the Chinooks averaged 19 flying hours a day. This was the largest helicopter assault in RAF history and the first opposed helicopter assault since the Suez Crisis in 1956.
To many people the Chinook is most associated with the conflict in Afghanistan where the Chinook was the principal airborne workhorse for almost two decades. The conflict saw the Chinook as the main air ambulance. As a flying emergency room, it saved the lives of many injured soldiers and Afghan civilians across the Helmand province by swiftly flying them back to the hospital in Camp Bastion. To some extent air transport was more important in this theatre of war because of the omnipresence of roadside bombs (IEDs) which gravely hindered normal road transport. In Afghanistan, the Chinook Force flew over 41,000 hours, extracted 13,000 casualties and its crews have been awarded numerous gallantry awards.
In 2014, the Chinooks distributed relief aid to thousands of Iraqi refugees trapped on a mountain in northern Iraq. The RAF dropped aid packages to stricken members of the Yazidi community hiding from Deash. But also closer to home the Chinook comes to the rescue of those in need. In June 2019, a Chinook was deployed to tackle the floods in Lincolnshire, dropping 1-ton gravel bags to create an artificial dam.
Around 10 years ago the Chinooks entered the digital age when their systems were upgraded with multifunction displays, a digital moving map display, an infrared detector, as well as (again) more powerful engines. In 2015, 14 new Chinook HC6 helicopters were purchased while several existing Chinooks were upgraded to a similar standard.
The Chinook is currently employed in Mali to support the French-led fight against jihadis. No. 1310 Flight is performing a range of missions from the transport of passengers and freight between main operating bases, to the insertion of troops to desert locations. To achieve this the detachment regularly overcomes the challenges of the environment, ranging from intense desert thunderstorms to searing heat, with temperatures regularly peaking above 40 degrees and seasonal flooding.
The RAF has not grown tired of the Chinook. Quite the opposite, it has ordered several new Chinooks with an advanced digital cockpit, a modernised airframe to increase stability and improve survivability, and a Digital Flight Control System, allowing pilots to hover in areas of limited visibility. A Sustainment Programme aims to extend the lives of existing Chinook for at least another 20 years, taking the Chinook fleet beyond 2040.
The RAF Museum Midlands has recently taken ownership of Bravo November and is now on public display. Come and visit Britain’s most famous helicopter.