Boeing Chinook (UK variants)

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Chinook
A Royal Air Force Chinook HC.2
Type Cargo helicopter
Manufacturer Boeing Helicopters
Maiden flight 1961-09-21
Status Active service
Primary user Royal Air Force
Developed from CH-46 Sea Knight
Variants CH-47 Chinook

The Royal Air Force is the second largest operator of the Boeing CH-47 Chinook (34 airframes) of the 16 nations that use the type.

RAF Chinooks have been widely deployed; serving in Operation CORPORATE (Falklands War), Operation GRANBY (Gulf 1991), large peace-keeping commitments in the Balkans, the evacuation of Sierra Leone, Afghanistan, Operation TELIC (Iraq 2003-), and the evacuation from Lebanon. The RAF's Chinook force also provides more routine support of the British Military, particularly in Operation BANNER (Northern Ireland). Two Chinooks are maintained as part of the Falklands Garrison.

Contents

[edit] Chinook HC.1

The Chinook CH-47A entered service with the United States Army in 1962. Following the retirement of the Bristol Belvedere in 1969, a similar design to the Boeing helicopter, the RAF required a new heavy-lift helicopter and ordered 33 HC.1s in 1978. These aircraft, which entered service in December 1980, were comparable to the CH-47C, fitted with Lycoming T55-L-11E engines. Eight more HC.1s were delivered from 1984 to 1986 with the CH-47D's Lycoming T55-L-712 turboshafts.

The replacement of the HC.1's metal rotor blades with glass fibre rotors saw these aircraft designated Chinook HC.1Bs. The main cargo of the merchant ship Atlantic Conveyor, which was sunk during the Falklands War, was three Chinook HC.1s of 18 Squadron and six Wessex helicopters of 848 Naval Air Squadron D Flight and all the second line repair and maintenance support equipment and stores. One Argentine CH-47C was captured during the war and returned to RAF service as a HC2.

[edit] Chinook HC.2

The US Army's next generation Chinook, the CH-47D, entered service in 1982. Improvements from the CH-47C included upgraded engines, fibreglass rotor blades, a redesigned cockpit to reduce pilot workload, redundant and improved electrical systems, an advanced flight control system (FCS) and improved avionics. The RAF returned their original HC.1s to Boeing for remanufacture to CH-47D standard, the first of which returned to the UK in 1993. Three additional HC.2s were ordered with delivery beginning in 1995.

6 further Chinooks were ordered in 1995 as Chinook HC.2As. The main difference in these and the standard HC.2 was the strengthening of the front fuselage to allow the fitting of an aerial refueling probe in future.

In July 2006, 3 Chinook helicopters of No.27 Squadron deployed to RAF Akrotiri in Cyprus to evacuate British citizens from Lebanon. The squadron also flew the EU foreign affairs representative Javier Solana to Beirut at the start of the crisis.

[edit] Mull of Kintyre crash

Main article: Chinook helicopter crash (1994)

On 2 June 1994 at about 1800hrs a RAF Chinook helicopter ZD576 (callsign F4J40), carrying almost all the UK's senior Northern Ireland intelligence experts, crashed on the Mull of Kintyre, Scotland killing all on board; 25 passengers plus 4 crew.

An RAF board of inquiry found that there was no conclusive evidence to determine the cause of the crash. However, two air marshals, on reviewing the evidence, found the two pilots guilt of gross negligence.

This ruling proved highly controversial; a subsequent Fatal Accident Inquiry, House of Commons Defence Committee report and Commons Public Accounts Committee have all either left open the question of blame or challenged the original conclusion. Following campaigning, a new inquiry was held, taking place in the House of Lords from September to November 2001. The findings were published on January 31, 2002, and found that the verdicts of gross negligence on the two pilots were unjustified.[1]

[edit] Chinook HC.3

8 Chinook HC.3s were ordered in 1995 as dedicated special forces helicopters. By 2006 the helicopters were still to enter service. The procurement was described by the Edward Leigh, then Chairman of the Public Accounts Committee, "as one of the most incompetent procurements of all time."[1]

The HC.3s were to be effectively low-cost variants of the US Army's SF Chinook, the MH-47E. The HC.3s would include improved range, night vision sensors and navigation capability. The eight aircraft were to cost £259 million and the forecast in-service date (ISD) was November 1998 (defined as delivery of the first six aircraft). As work proceeded, it became evident that displays for the weather radar and other systems anticipated for an avionics upgrade programme (put to contract in 1997) would not fit inside the existing cockpit.

One potential solution was to adopt a fully digital cockpit, as used by Chinooks purchased by the Royal Netherlands Air Force. However, this was not affordable within the funding available for the HC3 programme, and a hybrid solution was adopted, incorporating elements of the existing analogue cockpit and the new digital systems and displays. In March 1998 the new ISD was set at January 2002.

The problem seems to have been a lack of definition of requirements by the Ministry of Defence. Of 100 separate requirements only 30 were defined in the contract. All the aircraft were accepted from Boeing by December 2001, meeting, and in some cases exceeding, the contract, but none have so far been accepted into service. A key issue is that the Chinook HC3's unique, hybrid digital/analogue cockpit is reliant on software to operate. However, the contract did not specify that software documentation and codes should be analysed in accordance with UK standards in order to demonstrate the integrity of the software. It has not, therefore, been possible to demonstrate that the flight instruments meet these standards. The idea that the systems would be proven by the RNAF aircraft proved unfounded due to the unique configuration of the HC3.

One of the main contractors for the avionics system has recently indicated that it would allow access to some software data. However, the process of analysis is time-consuming and expensive and, in addition, there is no guarantee of a successful outcome because the legacy software is not amenable to the techniques required to confirm the robustness of software design. Consequently, the Chinook HC3 is currently restricted to day/night flying above 500 feet in clear weather, and where the pilot can fly the aircraft solely using external reference points without relying on the flight displays. These restrictions mean that the helicopters cannot be used other than for limited flight trials.

Another problem is the corrosion allegedly suffered during storage at Boeing. It was reported in 2003 that the US Army were interested in buying the 8 HC.3s, allowing the RAF to purchase MH-47Gs. However, following inspection of the aircraft the US Army declined this option. One HC.3 was damaged during delivery, rolling backwards into a crane at Bristol docks on July 20, 2001. Damage was significant but repairable.

Air Forces Monthly reported in November 2006 that The Defence Aviation Repair Agency will likely receive a contract to install the Thales "TopDeck" avionics system on the Chinook HC.3s.[2] If and when the HC.3s enter service they will join 7 Squadron at RAF Odiham.

The MOD has announced that work will begin immediately in converting the helicopters from special forces support to battlefield support helicopters. The programme is estimated to cost £50-60 million and will make the aircraft available within the next 2 years.[3]

[edit] Reputation in the RAF

Whilst the RAF has many types of helicopters in active service, the Chinook has proven itself one of the most effective. One particular example, serial ZA718 and also known by its original squadron code 'Bravo November', has seen action in every major operation the RAF has been deployed to in the helicopter's 25-year service life.

Bravo November went to the Falkland Islands in 1982 to spearhead the British landings there along with three other Chinooks. However, the container ship they were being transported on - the Atlantic Conveyor - was attacked on 25 May 1982 by an Argentine Navy Dassault Super Étendard with an Exocet sea-skimming missile. Although the rest of the aircraft were destroyed, Bravo November was airborne on an engineering test flight at the time of the attack. Having survived the destruction of the ship, she managed to make it safely to the aircraft carrier HMS Hermes.

Later in the conflict ZA718 ran into trouble during a night mission transporting guns to the SAS when pilot Squadron Leader Dick Langworthy, unable to see clearly through a thick snow shower, hit the sea at around 100 knots (175 km/h) due to a faulty altimeter, throwing up spray and flooding the engine intakes. Fortunately Langworthy and his copilot managed to get the helicopter back in the air. With the radio damaged and unable to navigate, Bravo November returned to San Carlos and a quick inspection revealed the impact had caused little more than dents to the fuselage and damage to the radio systems.

ZA718 Bravo November went on to serve in Lebanon, Germany, Northern Ireland, Kurdistan and Iraq, being the first British helicopter to land Royal Marines ashore in Iraq.

Two pilots of ZA718 have been awarded the Distinguished Flying Cross.

[edit] Chinook squadrons

[edit] Specifications (Chinook)

General characteristics

  • Crew: 3-4 (pilot, copilot, one or two air loadmasters - depending on aircraft role)
  • Length: 30.1 m (98 ft 9 in)
  • Rotor diameter: 18.3 m (60 ft 0 in)
  • Height: 5.7 m (18 ft 8 in)
  • Empty weight: 10,185 kg (22,450 lb)
  • Loaded weight: 12,100 kg (26,680 lb)
  • Max takeoff weight: 22,680 kg (50,000 lb)
  • Powerplant: 2× Honeywell T55-L-712 turboshafts, 2,800 kW (3,750 hp) each

Performance

Armament

[edit] References

  1. ^ "Chinook blunder 'left RAF short'", BBC News, 2004-04-07. Retrieved on November 16, 2006.
  2. ^ Jon, Lake. "Fleetlands To Fix Chinook HC.3s?", Air Forces Monthly, Key Publishing Ltd., December 2006, p. 4. Retrieved on November 15, 2006.
  3. ^ "More battlefield helicopters for UK Armed Forces", Ministry of Defence, 2007-03-30. Retrieved on March 31, 2007.
  • HC.3 information edited version of NAO: Battlefield Helicopters
    "All material may be downloaded, copied or reproduced free of charge in any format or medium without requiring specific permission."

[edit] Related content

Related development

Comparable aircraft

See also

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