AgustaWestland EH101

From Academic Kids

The AgustaWestland EH101 is a medium-lift helicopter originally developed as a joint venture between Westland Helicopters in the UK and Agusta in Italy for military applications but also marketed for civil use.

AgustaWestland Merlin HC3
AgustaWestland Merlin HC3


In 1977, the UK Ministry of Defence issued a requirement for a new anti-submarine warfare (ASW) helicopter to replace the Royal Navy's Westland Sea Kings. Westland responded with a design called the WG.34 that was approved for development. Meanwhile, the Marina Militare (Italian Navy) was also seeking a replacement for its (Agusta-built) Sea Kings, leading Agusta to a series of discussions with Westland about the possibility of a joint development. This culminated in the joint venture being finalised in November 1979 and a new company (EH Industries) being formed to manage the project the following year. EH is an abbreviation for Elicottero Helicopter, incorporating both the English and Italian words for "helicopter." As the design studies progressed, EHI became aware of a broader market for an aircraft with the same broad capabilities required by the British and Italian navies, leading to a more generalised design that could be customised for specific customers and applications. After a lengthy development, the first prototype flew on October 9 1987. EH Industries no longer exists, having been incorporated into the parent when the two companies merged.



The Royal Navy's final order was for 44 ASW machines, originally designated Merlin HAS Mk.1 but soon changed to Merlin HM Mk.1. The first fully operational Merlin was delivered on May 17 1997, entering service on June 2 2000. All aircraft were delivered by the end of 2002.

The Royal Air Force ordered 22 transport helicopters designated Merlin HC3, the first of which entered service on December 11 2000.

The UK is considering the Merlin as a replacement for the Westland Sea King ASaC7 in the Airborne Early Warning (AEW) role.


The first Italian Navy production helicopter (M.M.I. 01) was first flown on the 4th October 1999 and it has been officially presented to the Press on the 6th December 1999 at the Agusta factory. The delivery to Italian Navy started at the beginning of 2001. The italian Government has signed a contract to procure 16 EH101 helicopters that will be delivered to Italian Navy in the following variant: 8 anti-surface and anti-submarine(ASW)aircrafts; 4 aerly-warning(AEW)aircrafts; 4 utility aircrafts. (see [1] (

United States of America

Also in 2001 AgustaWestland signed a deal with Lockheed Martin to market the aircraft in the US under the designation US101. It competed for the VIP and "Marine One" Presidential transport roles currently carried out by H-3 Sea King or the smaller UH-60 Black Hawk. The US101 will be built in the United States and fitted with largely American systems and equipment, General Electric turboshafts for example.

On 28 January 2005, the US101 was announced as the winner of the contest to supply the next Marine One helicopter for the transportation of the President and other VIPs. In doing so, it beat the Super Hawk, Sikorsky's contender, and became the first non-Sikorsky helicopter to fulfill the Marine One role since 1957. The order is for 23 aircraft, to equip the Marine One squadron, HMX-1.


Canada has had a troubled history with the EH101. Following the lead of the UK and Italy, the Canadian government placed a $4.4 billion (CAD) order in 1987 for 48 (later 42) EH101s to replace the Canadian Armed Forces's CH-124 Sea Kings and CH-113 Labradors. These were to be assembled in Canada under the designations CH-148 Petrel (33 originally, reduced to 28) and CH-149 Chimo (15) in the anti-submarine warfare (ASW) and air/sea search and rescue (SAR) roles respectively. The whole programme was cancelled, however, after a change of government in 1993, leading to the payment of $0.5 billion in cancellation penalties.

In 1998, the Canadian government (with the same Liberal government in office) announced that the CH-113s would now be replaced by a new search-and-rescue variant of the EH101, carrying the designation CH-149 Cormorant. Unlike the Petrel/Chimo contract, these fifteen aircraft were to be built entirely in Europe. The Canadian government refers to these machines as AW 320s, carefully avoiding the EH101 name. The first two aircraft arrived in Canada in September 2001 and entered service the following year.

When it became obvious that the Sea Kings were in need of immediate replacement, the EH101 was again part of a Canadian competition (the Maritime Helicopter Project), versus the Sikorsky H-92, for a total price tag of $5 billion. The Sikorsky entry won the competition on July 23, 2004, despite the S-92 having never seen active service with any country; it is to be known as the CH-148 Cyclone.

Controversy again followed this procurement process, centering around several points:

  • Political and bureaucratic interference in the military's procurement process, resulting in the separation of the airframe from the onboard avionics. A similar separated (and bungled) procurement process was seen during the CP-140 Aurora purchase in the late 1970s and early 1980s. Separation of the airframe permitted the government to look at alternatives to the previously fiscally (and operationally) attractive EH101.
  • The alleged unwillingness of Paul Martin's Liberal government to select an aircraft which had been expensively rejected by his predecessor, Jean Chrétien, a few years earlier; the Liberals were frequently accused of rigging the selection process against the EH101.
  • Nearly $1.2 billion in industrial offsets by Sikorsky; the price per aircraft was lower than EH Industries could offer. This because Sikorsky, having never sold the S-92 military model, was willing to significantly subsidise the Canadian purchase.
  • The inability by Sikorsky, some say, to prepare the S-92 for military use. It should be noted that the S-92 is merely an enlarged version of an already-flying maritime patrol helicopter, the SH-60 Seahawk, and that Sikorsky has a long tradition in the maritime patrol field.
  • Allegations that Sikorsky would be unable to meet the contracted delivery deadlines, causing Canada to go even longer without an adequate navy helicopter.

The CH-149 variant of the EH101 was grounded for several weeks in 2004 due to cracks in tail rotor blade hubs, however in November, 2004, AIRCOM permitted flight operations to resume.


The Tokyo Police became the first civil customer for the type when they purchased a single example in 1998. In 2003, the Japanese Marine Self Defence Force announced an order for 14 aircraft to use in the ASW role.


In 2001, both Portugal and Denmark announced purchases of the EH101 for SAR duties.

Specifications (Merlin HM.1)

General Characteristics

  • Crew: four
  • Capacity: 30 seated or 45 standing troops, or medics and 16 stretchers
  • Length: 74 ft 10 in (22.81 m)
  • Main rotor diameter: 61 ft 0 in (18.59 m)
  • Height: 21 ft 10 in (6.65 m)
  • Main rotor area: 2,992 ft² (271 m²)
  • Empty: 23,150 lb (10,500 kg)
  • Loaded: lb ( kg)
  • Maximum takeoff: 32,188 lb (14,600 kg)
  • Powerplant: 3x Rolls-Royce/Turbomeca RTM322-01 turboshafts, 2,312 shp (1,725 kW) each


  • Maximum speed: 192 mph (309 km/h)
  • Range: miles ( km)
  • Service ceiling: ft ( m)
  • Rate of climb: ft/min ( m/min)
  • Main rotor loading: lb/ft² ( kg/m²)
  • Power/Mass: hp/lb ( kW/kg)


External links

Related content

Related development:

Comparable aircraft: NHI NH90 - Sikorsky S-92

Designation sequence:

See also:

Lists of Aircraft | Aircraft manufacturers | Aircraft engines | Aircraft engine manufacturers

Airports | Airlines | Air forces | Aircraft weapons | Missiles | Timeline of aviation

pt:AgustaWestland EH101

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