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Normalair Garrett Limited (NGL), or Normalair, was a British manufacturing company based in Yeovil, Somerset, England. It manufactured high altitude life support equipment for the aerospace industry. It is now a wholly owned subsidiary of Honeywell International Inc known as Honeywell Aerospace Yeovil (HAY).

The company originally grew out of the Westland Aircraft Company who in 1933 enabled the Houston Everest expedition to make the first ever flight over Mount Everest, using oxygen and heating systems - precursors of the systems that would eventually be produced by Normalair.

Westland Aircraft produced a cabin pressurisation control valve in 1941 for use in the Westland Welkin high altitude fighter bomber aircraft. Though the Welkin never got into full-scale production the same valve was used in Mosquito, Wellington and Spitfire aircraft.

Formation of the company[edit]

At the end of World War II, Westland had decided to focus on building helicopters, for which their high altitude technology was of no use; and on 15 March 1946 Normalair Limited was established on the Westland site in Yeovil.[1] Ted Boulger was appointed general manager. with J Fearn appointed as Westland Board Director with responsibility for the new company.

During the 1950s the company grew and continued to focus upon providing equipment that would allow aviators to operate at high altitude. In 1951 the company signed an agreement with the Eclipse Pioneer division of Bendix Aviation, now also owned by Honeywell, to manufacture and modify oxygen breathing regulators for aircrew. During this period, the Royal Aircraft Establishment gave the company responsibility for all military oxygen work and as a result acquired complete life support systems capability including oxygen masks and emergency oxygen supply.[2]

In anticipation of the long range support needed by the de Havilland Comet Normalair set up subsidiaries in Melbourne, Australia and in Toronto, Ontario, Canada. The company employed 250 people in 1954 and in the same year produced LOX (Liquid Oxygen) converters for the German Air Force, F-86 Sabre.


In 1957 the publication of Duncan Sandys' Defence White Paper caused the cancellation of many aircraft projects. The company decided to diversify into other markets and took a licence from Drägerwerke, of Germany, to produce compressed air diving and oxygen breathing apparatus. Normalair achieved most success with portable oxygen systems with the equipment supplied for the first successful ascent, by Tenzing and Hillary, of Mount Everest.[3]

Relatively short lived was Normalair's entry into the automotive air conditioning market where the systems were optional extras on Wolseley Wolseley 6/110,[4] Austin Westminster 110, Vanden Plas Princess, Land Rovers and some Rolls-Royces. However the company was some thirty years too early as demand for air conditioned cars in Europe did not materialise, the company withdrew from the market in 1964.

In 1960, further agreements with Bendix brought licensed production of hydraulic servo valves to Normalair's range of products. This expertise was then developed into for electro-hydraulic servo valves, actuators and lightweight solenoid operated hydraulic valves. The company also produced marine hydraulics and valves for submarines.

Also in 1960 the Industrial Electronics Division was formed to use Data Logging technology brought from Saunders-Roe, when parent company Westland took them over. At the same time the company was involved with development and production of regulators for Harrier and UK Phantom aircraft.

Normalair's high altititude laboratory included a chamber large enough to accommodate a full size mock-up of the Concorde fuselage. This was used for trials simulating the effects of supersonic cruise at up to 60,000 ft - nearly twice the operating altitude of contemporary airliners. As well as these tests, Normalair developed the cabin pressure control equipment providing a comfortable environment for passengers.

Garrett Corporation shareholding[edit]

The company won a Queens Award to Industry for Export in 1966 and the Garrett Corporation took a 48% shareholding in the company, which was subsequently renamed Normalair-Garrett Limited (NGL). At this time the company had more than 1,300 employees.

NGL took over one of its main competitors, Teddington Aircraft Controls, in 1971. In the same year the company also acquired Aircraft Supplies Limited of Bournemouth, whose premises were used to set up NGL's important product support activities. The company had entered numerous license agreements during its history but in this year it agreed to license manufacture of oxygen and environmental control systems to Hindustan Aeronautics Limited, of India, for production of the HJT 16 aircraft.

Several major contracts were won in 1972 to supply the Multi Role Combat Aircraft (MRCA) later to be named Panavia Tornado. In the same year the company acquired the Westland foundry business in Hayes and transferred it to the Drayton Hydroflex premises in Chard, Somerset. In that year also, Julian Knott set the world altitude record for a hot air balloon of 35,971 ft using a balloon supplied with NGL oxygen equipment.

NGL won several contracts in 1974 to supply the HS146 regional jet, now called the BAe 146 with air conditioning and air systems management equipment.

Diversification continued with the purchase of Facet Enterprises filtration licenses from Voles in 1976. In the same year Normalair’s filtration division was formed in the former glove making factory at Shepton Beauchamp facility, where it remained for 10 years before being moved to the Lynx Trading Estate in Yeovil near to the main plant.

The last vapour cycle air conditioning systems developed by Normalair were fitted to export versions of Alvis Stormer and Scorpion armoured vehicles, and the Khaled tank (a version of the Centurion sold in the Middle East).

The company later opted out of making vapour cycle systems to concentrate on air cycle systems only. Through luck or foresight, this decision was later to be vindicated when 15 years later; the Montreal Protocol saw the end of Chlorofluorocarbon and FC based systems.

In 1977 NGL began development of its first in-house designed aircraft data recorder, a sealed maintenance recorder for the McDonnell Douglas (now Boeing) F/A-18 Hornet A/B. A data recorder that had to meet unprecedented environmental and accuracy specifications and was Normalair’s first order for US defence equipment. The F/A-18 unit placed Normalair at the forefront of aircraft recorder technology and a dedicated electronics division was set up at Clarence Street, near to the former Huish football ground.

The height of Normalair’s fame came with the appearance of the Deep Dive 500 closed circuit breathing system (Scuba Set) which appeared in the James Bond, For Your Eyes Only (film). The system minimised the emission of bubbles and made it suitable for covert naval operations.


  1. ^ "Patran at Normalair-Garrett". Aircraft Engineering and Aerospace Technology. 60 (2): 26–27. 1988. doi:10.1108/eb036574. ISSN 0002-2667. 
  2. ^ "Round the stands". Flight. 1961. Retrieved 2009-04-03. 
  3. ^ Unsworth, Walt (2000). Everest: the mountaineering history. The Mountaineers Books. p. 310. ISBN 978-0-89886-670-4. 
  4. ^ "Wolsley 6110". Unique Cars and Parts. Retrieved 2009-04-03. 


  • Celebrating fifty years of Normalair - A brief history. by M.P. Bednall
  • Reference: A W Gregg for source information up to 1974